$91 POSTERS P-01 BRAIN MRI ATTENUATED SEQUENCE

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WITH TURBO FLUID INVERSION RECOVERY

Salvolini U., Righini A. *, Polonara G., Santino P. **, Farabola M.*, Leonardi M.* NeuroradioIogy Department, Ospedale Generale RegionaIe, Ancona, Italy. *Neuroradiology Department, Ospedale Maggiore, Milan, Italy. **Siemens Italia, Milan, Italy. P u r p o s e : The fluid-attenuated inversion recovery (FLAIR) sequence provides heavily T2 weighted images with low signal from components with T1 close to CSF value. FLAIR has proven to be valuable in the assessment of several different brain lesions. However, FLAIR studies may not be easily performed routinely because of the long acquisition time. We tested a turbo spin-echo sequence with inversion recovery prepulse for suppression of fluids with long T1 in patients with brain ischemia, neoplasms, white matter disease, infections. Material and Methods: More than 40 patients were studied on a 1T system (Impact; Siemens AG). We compared double echo turbo SE (TR = 2300, TE = 1485, matrix= 250x256, acquisition time = 2rain. 01sec) and turbo IR fluid attenuated sequence (TR = 9000, TE = 150 TI = 1900, matrix= 240x256, acquisition time = 4rain. 57sec). The fluid attenuated sequence allowed 8 slices to be collected, all with the same TI. In some cases a Gd-DTPA enhanced T1 weighted study was also performed. Results: Some lesions were identifiable on the fluid attenuated images but not on the standard turbo SE T2 weighted ones. Many lesions detected on standard turbo SE appeared to be more conspicuous after fluid attenuation. The cystic component of some neoplasms was better characterized as well. C o n c l u s i o n : Turbo IR fluid attenuated sequences provide a contrast similar to FLAIR but in shorter acquisition time and better resolution.

P-02 I N D I C A T I O N S F O R TI W E I G H T E D T U R B O SPIN ECHO SEQUENCES IN M A G N E T I C R E S O N A N C E I M A G I N G OF THE BRAIN

Fellner F 1, Trenkler J 1, Feichtinger R 1, Obletter N 2 Bohm-Jurkovic H 1 Department of Neuroradiology, OberOsterreichische Landesnervenlclinik, Linz, Austria. 2 Department of MRI, Klinikum Ingolstadt, Germany P u r p o s e : Turbo spin echo sequences are in the meantime a welt established method in magnetic resonance imaging of the brain. Up to now, however, these sequences facilitated only T2 and proton density weighted contrast. In this study 2D Turbo spin echo

sequences are introduced that supply T1 weighted image contrast. Material and Methods: This study was performed using a MR scanner with a field strength of 1.0 T (Magnetom "Impact", Siemens). The scanner supplies a maximal gradient field strength of 15 mT/m with a rise time of 1 ms. This hardware allows application of Turbo spin echo sequences with short effective echo time, short echo train length and short inter echo spaces providing T1 weighted image contrast. T1 weighted Turbo spin echo sequences with and without fat saturation were compared with conventional T1 weighted sequences. 30 patients suffering from tumors and i n f l a m m a t o r y lesions r e s p e c t i v e l y post neurosurgery were examined. Lesion visibility and contrast behaviour in both sequence types was evaluated by three independent observers. Results: T1 weighted Turbo spin echo sequences allow application of maximal 12 slices for TR not longer than 600 ms. Therefore their applicability had to be restricted to special indications as examinations of sella, orbita and cerebellopontine angle. Minimal slice thickness of these sequences was 3 mm on the contrary to conventional sequences which facilitated a minimal slice thickness of 2 mm. By application of T1 weighted Turbo spin echo sequences measure time could be reduced to 40 %. Both sequence types revealed similar contrast behaviour of anatomical structures and of lesions. Lesion conspicuity was not significantly reduced in Turbo spin echo sequences compared to conventional T1. C o n c l u s i o n : T1 weighted Turbo spin echo sequences are a valuable tool for special magnetic resonance imaging of the brain (cerebellopontine angle, sella and orbita). Measurement time reduction can be used to shorten examination times or to improve image quality.

P-03 U S E F U L N E S S OF P H A S E C O N T R A S T MR I M A G I N G FOR THE A S S E S S M E N T OF THE E F F I C I E N C Y OF VENTRICULOCISTERNOSTOMY

Brugi~res P., Ricolfi F, Decq P, Sadik J. C, Gaston A. Henri Mondor Hospital, Crdteil, France Purpose: To precise the patterns of CSF velocities in obstructive pathology of the medial CSF pathways before and after ventriculocisternostomy. Material and Methods: A 2D-FISP (TR/TE= 70/13, a= 15 ~ sagittal craniocervical study with velocity encoding in the craniocaudal direction and flow sensitivity set to +/- 100mm/s was realized on 14 patients - M/F= 13/4, mean age = 36,4 y (10 - 63 y)treated with venticulocisternostomies for stenosis of aqueduct (6 idiopathic ,4 tumoral), or obstruction of the CSF pathways of the fourth ventricle (2) and on 2

S 92 POSTERS patients with cystocisternostomies for suprasellar arachnoid cysts. Results: Normally a synergistic pattern of the CSF flow is observed in the cisterns and the ventricular CSF p a t h w a y s and is c h a r a c t e r i z e d with a craniocaudal systolic flow and a caudocranial diastolic flow. Loss of the synergy is constantly observed in obstructive pathology of the CSF pathways. After v e n t r i c u l o c i s t e r n o s t o m y , high velocities in the interpedoncular and prepontine cisterns and the recovery of a synergistic evolution of the CSF flow in the third ventricle and in the basal cisterns were observed in 11 patients with a good post operative clinical status. One patient with a poor clinical result had low cisternal velocities. In suprasellar arachnoid cysts, ventriculocystocisternostomy appears to be more convenient than ventriculocystectomy with regard to CSF flow patterns and clinical status. Conclusion:Phase-mapping MR imaging is a valuable technique for the evaluation of the permeability of ventriculocisternostomies and of ventriculocystocisternostomies.

P-04 O B S T R U C T I O N OF T H E A C Q U E D U C T OF S Y L V I U S IN V E I N OF G A L E N V A S C U L A R M A L F O R M A T I O N D E M O N S T R A T E D BY C I N E PC MR

Brunelle F., Sebag G, Baraton J. Service de Radiologie Pddiatrique, H6pital des EnfantsMalades, Paris, France P u r p o s e : To p r e c i s e the m e c h a n i s m of hydrocephalus in patient with vein of Galen vascular malformation. Material and Methods : Two children with vein of Galen vascular malformation were studied with cine PC MRI to assess quantitatively the CSF flow though the sylvius aqueduct. One patient was studied pre and post embolization. Cine PCF includes a 5 mm scan perpendicular to the sylvius aqueduct. Velocity was encoded in the direction of the aqueduct at a maximum speed of 10 cm/s. 16 phases are acquired through the cardiac cycle. Flow was calculated and plotted against time with a dedicated software: Vcalc. Results : In the two patients the dilatation of the vein of Galen occluded the aqueduct as no flow or minimal flow was present. In the patient studied after embolization restoration of a normal flow was observed. C o n c l u s i o n : Many hypotheses are described to explain hydrocephalus associated with vein of Galen malformation. Increased venous pressure and direct compression of the aqueduct are the two majors hypotheses. We demonstrate in two cases that direct compression of the aqueduct directly impede CSF flow

P-01 - P-116 P-05 STUDY OF A NEW CHRONIC H Y D R O C E P H A L U S M O D E L IN P I G L E T S BY MRI AND SRMN P31.

Collombier L., Lherbier B, Walker P, J Escanye J.M, Laurens M.H, Thouvenot P, Bertrand A. Laboratoire de Biophysique, Facultd de Mddecine de Nancy, France Purpose: The aim of this study was to validate a new chronic hydrocephalus model in piglets. MRI has been used to evaluate hydrocephalus, and 31P NMR spectroscopy used to estimate metabolic brain failure. Material and Methods: Hydrocephalus was induced in eleven 3.5 weeks old piglets by transcutaneous injection of 2 ml Kaolin sterile solution at 20% into cisterna magna.At the same time cerebral morphology and metabolism were studied with a 2.35 Tesla, 35 cm bore, superconducting MR unit (Bruker BC 24-40) before kaolin injection and once a week during four weeks.The imaging coil used for MRI was a homemade 16 line "bird-cage" tuned at 100.2 MHz. MRI sequences began by gradient echo coronal slices (TR = 100 ms, slice thickness = 10 mm) and continued with spin echo T2 (2500 ms/100 ms/10 ram) slices. To assess hydrocephalus development a ventricular index (VI) was calculated on the anterior slice in gradient echo and spin echo T2 (VI is defined as the ratio of the greatest width of frontal horns to brain diameter at the same level) .31P MRS was performed using a twoturn 5 cm diameter surface coil tuned at 40.4 MHz, fixed to the frontoparietal region. Three spectra were obtained with pulse width of 110, 200, 300 ms each with 200 scans. Deconvolution spectra show the characteristic resonance of the a, b and g P 31 nuclei of adenosine triphosphate (ATP), phosphocreatine (Pcr), phosphodiesters (PDE), inorganic phosphate (Pi) and phosphomonoesters (PME). Pi/Pcr ratio is used as indicator of energetic brain metabolism, PME/PDE ratio as indicator of anabolic/catabolic activity of the phospholipid metabolism in brain. Results" Ventricular Index is increased on gradient echo slices in hydrocephalus piglets (0.46) versus non hydrocephalus piglets (0.32) .Pi/Pcr ratio is normal in acute stage of hydrocephalus (one week) but significantly decreased in subacute stage (- 30 %) (2 3 weeks) and subnormal at chronic stage (4 weeks).PME/PDE ratio decreases in proportion of hydrocephalus (- 20 %) attesting a delay of myelination and/or myelin destruction in hydrocephalic piglets. Conclusion: This pilot study proves that the piglets provide a new and valid chronic hydrocephalus model. MRI offers a non invasive method for observing and measuring (VI) ventricular increase. SRMN P 31 shows cerebral metabolic alterations : transitory energetic brain failure and brain phospholipid catabolic activity increasing with development of hydrocephalus. This suggests a delay in myelination

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and/or myelin destruction in hydrocephalic piglets. Further studies are necessary to clarify the changes demonstrated, with a control population to evaluate normal m y e l i n a t i o n in piglets, and with MR spectroscopy localization methods because brain alterations in hydrocephalus predominate in the periventricular area more than in the cortical area.

P-06 POLYMORPHISM SARCOIDOSIS

OF

INTRACRANIAL

Caparros-Lefebvre D. Blond S, Ruchoux M.M, GirardButtaz I, Pertuzon B, Wallaert B, Petit H, Pruvo J.P. Dept of Neurology, Neuroradiology, Neurosurgery and Neuropathology, CHRU Lille, France Central nervous system lesions resulting from sarcoidosis occur in 5% of cases, but intracranial masses are uncommon. We report 3 new cases of pseudo-tumoral intracranial lesions, due to sarcoidosis, with unusual imaging features. The first patient was admitted for left facial myoclonus, headache and vertigo. Sarcoidosis has been diagnosed previously, upon conjonctival biopsy. CT scan revealed diffuse right temporoparietal hypodensity and large enhancement of the meninges, bilaterally. MRI T2 weighted images showed abnormal high signals involving the right insula and temporal lobe, suggesting vasogenic oedema. The 2nd patient d e v e l o p e d a right hemiparesis, which improved transiently but worsened twice during the 2 year follow-up. CT scan and MRI revealed numerous small granuloma in the left corona radiata, and one in the striatum. Sarcoidosis had been diagnosed few weeks before, upon infiltrative lesions of the lungs and mediastinal lymph nodes. The 3rd patient was admitted for a unique general seizure. CT scan showed an enlargement of the left temporal horn, due to an enhanced left periventricular lesion. MR! after gadolinium showed an enhanced round lesion which encircled the ventricle horn. Stereotactic brain biopsy revealed granuloma with multinucleated giant and epithetioid cells. Biopsy of mediastinal adenopathy confirms sarcoidosis, which was clinically silent until the first seizure. Clinical and r a d i o l o g i c a l i m p r o v e m e n t was obtained in all 3 cases after corticoid therapy. In all 3 cases, CT and MRI showed unusual images of intracranial process, mimicking respectively infiltrative glioma, meningioma and ependymoma. Less than 30 cases of intracranial mass sarcoidosis have reported during the last 35 years, but neuroradiological features were poorly defined, with only CT images. These 3 new cases of cerebral sarcoidosis r e v e a l e d the p o l y m o r p h i s m of the sarcoidosis lesions in MRI.

P-07 D Y N A M I C - M R IN THE D E T E C T I O N OF L O W GRADE GLIOMAS

Walecki J, Marszalek P, Chojnowski A Med Centre of Postgraduate Education, Warsaw, Poland An attempt to characterise grade of malignancy of glioma by analysing dynamic -MR images. In 69 patients with histologically confirmed low grade glioma/I/II W H O / w e r e studied. CT, MR and dynamic -MR were performed. In 60 cases (90%) dynamic MR improved quality of image and provided additional informations. In conclusion, we find that dynamic -MR is a very sensitive method for the detection of low grade gliomas. We have noticed usefulness of dynamic -MR in cases where routine enhanced CT and MR were not sufficient for precise diagnosis.

P-08 IS THE G L I O M A T O S I S C E R E B R I A RADIOP A T H O L O G I C A L L Y ENTITY ? Romero F.J., Ortega A *, Coscojuela P, Rovira A, Ibarra

B.Services of Neuroradiology and Neuropathology*Hospital General Universitario Vail d'Hebron., Barcelona (Spain) Gliomatosis cerebri is an unusual tumoral condition characterised by diffuse overgrowth of large parts of the central nervous system by glial cells, with preservation of the underlying neuronal architecture. P u r p o s e : We want to discuss about the neuroradiological findings in this rare neuroepithelial tumor and evaluate the role of the neuroimaging in this diagnosis "in vivo". Material and Methods : 6 patients, four males and one female, whose age range was between 23 to 65 years old, were examined by CT and/or MRI. All these patients had neuropathological study (biopsy or autopsy). Results : The clinical presentation were behavioural and mental changes, motor weakness and headaches. The radiological findings were : small ventricles; hypodense areas in CT or high intensity signal areas in T2WI; lost demarcation between gray and white matter in affected region and expansion of gyri with obliteration of intervening sulci. In all cases there was midline structures diffuse and more or less symmetric thickening. The pons and midbrain were involved. In two cases, the cortical enhancement simulated leptomeningeal dissemination. C o n c l u s i o n T h e term "gliomatosis" was no felt to be appropriate unless large area ( at least two usually three lobes ) of the brain are involved ( by CT or better M R I ) and the b i o p s y showed glial elements.We think that the gliomatosis cerebri may be considered as a radio-pathological entity where the

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neuroimage is the clue and pathological study by biopsy confirms the glial nature key of the process.

P-10 CT A N D MR F I N D I N G S IN P R I M A R Y A N D SECUNDARY INTRACRANIAL NON-HODGKIN L Y M P H O M A S (NHLs).

P-09 D I A G N O S I S A N D F O L L O W - U P BY MRI OF SEVEN CASES OF S U B E P E N D Y M O M A

Feliciani M*, Simo N**, Rovira A ***, De Juan M**, Gua rdia**, Zamora A *, Villanueva A *, Ruscalleda J**. *Diagnosis Medica, Barcelona **Hospital de la Sta. Creu i Sant Pau, Barcelona ***Udiat, Sabadell, Spain.

Hoeffel C., Boukobza M., Polivka M. *, Guichard J.P., Lafitte F., Re&ine d., Merland J.J. From Department of Neuroradiology and Therapeutic Angiography, H@itat Lariboisikre Paris (France) * From Department of Neuropathology, HOpital Lariboisikre Paris (France) P u r p o s e :Subependymoma is a rare, slow-growing, benign, non invasive tumor. With special reference to MRI findings and to enhanced MR images, there have been some isolated case reports but no series have been reviewed so far. We describe seven cases of surgically cured subependymomas diagnosed over a 7 years period, with emphasis on enhanced magnetic resonance imaging study. M a t e r i a l a n d M e t h o d s :The patients were 5 males and females, ranging in age from 17 to 73 years old (mean age = 50). All of them were symptomatic. MR examination included Tl-weighted sequences (n = 7), gadolinium-DTPA enhanced Tl-weighted sequences (n = 6) and T2-weighted sequences (n = 5). The imaging findings were retrospectively reviewed and correlated with operative and pathologic reports. Clinical and imaging post-operative follow-up was available in 6 cases. Results :The tumor was located in the fourth ventricle (n = 3), in the third ventricle (n = 1), in the cervical spine (n = 2) either intramedullary (n = 1) or extramedutlary (n = 1). In one case, they were multiple, localised in the posterior fossa. On MRI, the masses were well-demarcated except for one case, hypointense (n = 3) or isointense (n = 4) (relative to normal grey matter) on Tl-weighted sequences and hyperintense on T2-weighted images. They were heterogeneous in all but one case. The masses showed either no enhancement (n = 3), mild heterogeneous enhancement (n = 1) or pronounced heterogeneous enhancement (n = 2). One of the cases showed recurrence seven years after surgery. C o n c l u s i o n :MRI was useful in evaluating tumor location, size and extent but it did not help much in eliminating alternative diagnoses such as ependymomas.

P u r p o s e : T o evaluate the features of intracranial involvement of primary and secondary NHLs by means of CT and MR. Material and M e t h o d s : 1 4 patients (6 males, 8 females, age range=27-77 years) affected by NHLs with histologically proven intracranial involvement underwent contrast-enhanced CT and/or Gadoliniumenhanced MR investigations. 9 cases were primary (1 AIDS patient) and 5 secondary Iymphomas. Results:8 patients presented with a single lesion, 5 patients showed multiple lesions and in 1 case a leptomeningeal infiltrative pattern was found. 4 cases showed cortical localization of the lesions, 9 patients showed deep lesions and 1 patient showed a focal leptomeningeal localization. In one patient, who harboured multiple lesions, an infratentorial mass was found. Only in two cases was perilesional oedema absent. The remainder showed marked perifocal oedema and mass effect. The contrast enhancement, either on CT or MR images, was homogeneous in most cases, being partial and in homogeneous in larger tumours.8 patients displayed post-treatment (radiotherapy and chemotherapy in most cases) recurrence. In one case of secondary Iymphoma with leptomeningeal infiltration, the latter showed a significant progression despite the radiotherapy treatment. One case with a single lesion displayed a mass reduction after treatment. Follow-up data are not available in the remaining 4 cases. Conclusion:Intracranial primary NHLs occur in the 1.5-2% of all Iymphomas, while literature data about the involvement of CNS by systemic NHLs are debated and range between 8 and 50%. Lesions are usually of big size, often multiple and generally with prominent perifocal oedema. Contrast enhancement is always present, usually with a homogeneous pattern, although it is said that it does not reflect the actual extent of the tumor, which on histological grounds often p r o v e s to e x c e e d the limits of the e n h a n c e m e n t . I n t r a c r a n i a l N H L s are aggressive lesions, with a high rate of recurrence after surgery and a p o o r r e s p o n s e to r a d i o t h e r a p y and chemotherapy.

S 95 POSTERS P-11 M R I IN M E N I N G E A L C A R C I N O M A T O S I S Duca S*, Lobello G**, Crasto S*, Peretta P* *Arturo Pinna Pintor Foundation, MRI Department, Torino, Italy **Radiologic Department, City Hospital, Rivoli, Italy P u r p o s e : The authors examine their oncologic casuistic to look for m e t a s t a t i c m e n i n g e a l involvement both in cranial and spinal locations. Material and Methods: From 1200 head and spine secondary neoplastic cases, all examined with a 0.5 MR equipment, with T1, T2 and Gd T1 SE sequences, the authors find 40 cases with secondary meningeal neoplastic involvement. Results: Meningeal carcinomatosis was found in 40 cases (3.3%) and in 33 cases (82%) the diagnosis was possible only after contrast medium injection. C o n c l u s i o n s : Meningeal carcinomatosis is quite rare and MRI with contrast enhancement is actually the most sensitive tool to discover it. In our casuistic we found 40 cases (3.3% of 1200 head and spine MRI examinations with clinical suspicion of secondary neoplastic disease). In 37 cases there was a head and in 3 a spine involvement. In 30 cases it was possible to get correlations with neoplastic cells research in CSF, while in 10 cases the diagnosis was made on the clinical-MRI findings. In 32 cases we found only dural involvement, in 2 leptomeningeal carcinomatosis and in 6 cases a mixed involvement. In 33 cases (82%) the diagnosis was possible only after Gd DTPA injection.

P-12 CT F O L L O W - U P A F T E R S T E R E O T A C T I C R A D I O S U R G E R Y OF P R I M A R Y I N T R A C R A N I A L T U M O R S AND AVM-S Osztie E, Fedorcsak I, Horvath A. National Institute of Neurosurgery, Budapest-Hungary Purpose: Stereotactic radiosurgery is a relatively new treatment possibility of recurrent, multiple and spreaded intracranial tumors as well as of AVM-s in location with great operative risk. This procedure is well-tolerated by the patients and it can be performed on outpatients too. Material and Methods: From Nov. 91. to Dec. 93. we treated 14 patients with residual or inoperable AVMs, 9 primary intracranial tumors (2 meningiomas, 5 acoustic neurinomas, 1 germinoma and 1 hypophysis adenoma) and 8 patients with recurrent tumors (3 a c o u s t i c neurinomas, 1 glioblastoma, 1 ganglioglioma, 2 ependymomas and I m e d u l l o b l a s t o m a ) . The largest diameters were between 1 and 3 . 5 cm. The lesions received 13 -25 Grays delivered by a 9 MeV linear accelerator. Results: Our- follow-.Up CT examination showed that after radiosurgery the tumor growth stopped and the

P-01 - P-116 circulation of the AVM-s decreased or disappeared completely after 1,5-2 years. Tumor growth was found only in one case of acoustic neurinomas after I year following the therapy. We have got no serious side effect, but radiation induced oedema has occurred in 36%. Conelusion" We have concluded that a good local tumor control and complete occlusion of AVM-s can be achieved with radiosurgery. CT is a useful method in follow-up examination of tumour growth and it can provide basic information about decrease of AVM circulation.

P-13 STEREOTACTIC RADIOSURGERY IN MALIGNANTINTRACRANIAL TUMORS WITH LINEAR A C C E L E R A T O R (LINAC) BEAMS. Barat JL, Debaene A., Eskandari J. , Obry J.M, GomezA. Clinique Clairval - Marseille - France Purpose:The authors report their early experience in stereotactic radiosurgery in malignant brain tumors (primary or metastases). Material and Methods: From april 1993 to January 1994, 11 patients. Underwent a St6r6otactic Radio surgical treatment for 14 locations including 13 brain metastases and 1 astrocytoma.* Stereotaetically guided single dose irradiations of treatment volumes from 10 to 25 mm in diameter (mean, 18ram) have been performed with the multiple arc-convergent beam irradiation technique, using 15 MEV photons from a linear accelerator (saturne 43 GEMS, General Electric Medical System). The Fischer stereotactic treatment planning (S.T.P) system (Friburg, Fischer MET G M B H Germany), is used for CT guided stereotactic localization and treatment planning. 10 to 19 Grays (mean, 15 Gy) have been given to the tumor surface, corresponding to the 70 % isodose surface with respect to the dose to the target point (100%). The median number of beam arcs utilised was 7 (512). Results: There were 6 complete regressions (42%) in 4 patients. Partial response was observed in 4 cases, leading to an overall response rate over 70% (10/ 14).*There was no early toxicity observed. C o n e l u s i o n : This procedure is active and safe in the treatment of brain metastases and is time sawing for the patient (hospitalisation time 1 day only). The authors are now evaluating the advantage of a complementary hole brain irradiation in this setting.

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POSTERS P-14 NON - ENHANCED HYPOINTENSE CENTRAL BAND IN THE PITUITARY GLAND

Barrena R., Guelbenzu S., Gutierrez P., Sevilla G., Cacicedo E and Valero, P. Hospital Miguel Servet. Zaragoza. Spain During one year we have made a study on seventy patients with a clinical suspicion of micro adenoma and elevated prolactin level. All of them were evaluated by magnetic resonance imaging of the brain. The exploration was performed using sagittal and coronal T1 -weighted spin echo sequences. Coronal planes were obtained at sella turcica level, before and immediately after intravenous injection of gadopentate dimeglumine. In thirty two patients the hypophysis was normal, with a uniform signal and homogeneous enhancement. Micro adenomas were found in twelve patients. Their behaviour was the habitual one, a hypointense wellcircumscribed lesion in pre contrast studies without enhancement after gadolinium injection. It is well-known the in homogeneity that pituitary glands can present in relation to their vascular supply and cellular distribution like the variable behaviour of micro adenomas referred to their signal intensity and contrast enhance. It is important to stand out that in ten patients with stimulating symptoms of micro adenoma a nonenhanced hypointense central band in the pituitary gland was observed in post-contrast images. The results of this study will show a different and less frequent presentation of an abnormal glandular function. This glandular abnormality has not been described previously and magnetic resonance imaging of the hypophysis can show it.

P-15

C A R C I N O M A OF THE P I T U I T A R Y REPORT OF THREE CASES

GLAND

Tanji Ph. ; Barral F.G ; Beauchesne P ; Michel D ; Brunon J H@ital Bellevue, Saint-Etienne, France Primary malignant tumors of the pituitary gland are rare: less than fifty cases have been reported in the literature. In gross anatomy, the diagnosis of primary carcinoma is strongly suggested by the presence of metastases located outside the central nervous system. In the two first cases, bony metastases in one patient, cutaneous and liver metastases in the other patient, were diagnosed 2,5 years in mean after the establishment of pituitary primary carcinoma (confirmed at necropsis). It is very likely that in the third patient, typical lesions of primary carcinoma were recognized in gross anatomy but the patient is

still alive with loco-regional extension and without extra cerebral metastases.

P-16

F A L S E R E S I D U A L T U M O R ON L A T E POST OPERATIVE MR STUDIES FOLLOWING TRANSSPHENOIDAL RESECTION OF A PITUITARY TUMOR.

Cottier JP*, Aesch B**, Sonier C.B*, Yapi P*, Velut S**, Laffont J*, Jan M**.Service de NeuroRadiologie*, Service de Neuro-Chirurgie**, H@ital Bretonneau Tours, France. P u r p o s e : We report the MR appearance of three patients following transphenoidal resection of a pituitary tumor. Persistence of suprasellar and intrasphenoidal masses in the late postoperative period was diagnosed as residual tumor but these findings were not confirmed at second surgery. Material and Methods: Three patients were studied with MR following transsphenoidal resection of a pituitary tumor. Two tumors were intra and suprasellar macroadenomas (one prolactin adenoma and one nonfunctioning adenoma). The third tumor was an ectopic prolactin adenoma, only located within the sphenoid sinus. R e s u l t s : In the two cases of intra and suprasellar adenomas, late postoperative studies performed 4 and 6 months after surgery showed residual snprasellar enhancing lesion with deviation of the pituitary stalk and mass effect on optic chiasm. In the case of prolactin adenoma, elevated hormone level persisted. At second surgical exploration, the neurosurgeon found an encapsulated lesion constituted by fibrous tissue and blood, without any residual tumor. - In the case of prolactin adenoma located within sphenoid sinus, successive postoperatives CT examinations then MR studies (performed 7 years after surgery) showed a low intensity tissue on T1 weighted studies at the posterior part of the sphenoid sinus with a peripheral enhancing. After surgery, prolactin level had decreased hut hyperprolactinemia persisted. At second surgery, sphenoid sinus mucosa were normal. Conclusion: Enhancing residual mass on late postoperative MR studies is not always persisted tumor. It can represent suprasellar encapsulated lesions constituted by fibrous tissue and blood. It can also represent normal post surgical change in sphenoid sinus.

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P-17 CAVERNOMAS AND EPILEPSY: C O M P A R A T I V E A S P E C T S OF MRI B E F O R E AND AFTER SURGERY

P-18 MALFORMATIONS OF THE MEDIAL T E M P O R A L LOBE : M R STUDY IN 200 A D U L T PATIENTS WITH PARTIAL EPILEPSY.

Lupescu I., Turjman F., Tournut Ph., Sindou M., Froment J. C.H6pital Neurologique et Neurochirurgical P. Wertheimer - Lyon (France)

Lehdricy S.1-2, Sdmah F 1, Dormont D 1, Cldmenceau S 1, Granat 0 3, Baulac M 1. Services de 1 Neurologie, Neurochirurgie, Neuroradiologie, H@itaI de la Salp@tri@re, Paris; 2 Radiologie, H6pital Beaujon, Clichy; 3 Radiologie, H6pital Saint Joseph, Paris, France.

A prospective study of cavernomas operated on for epilepsy was performed with pre and postoperatory MRI.13 patients among 17 operated had pre and postoperatory MRI examinations (SIEMENS 1.5 T). All the patients, 8 males and 5 females, with a mean age of 34 years, tCresented an epilepsy (generalised crisis in 5 cases, focal crisis in 4 cases and mixed crisis in 4 cases). The average time was 2 months between the pre-operatory MRI exam and surgery, and 1.5 years between surgery and the postoperatory MRI control. All patients were examined with the same protocol: axial, 6 mm thick, parallel to the orbitomeatal plan slices, T2-weighted spin echo-sequence. The postoperatory MRI examinations included also T1weighted sequences (sagittal slices in 2 cases, coronal slices in 8 cases and 3D acquisition in 2 cases).The cerebral localisation was unique for all the 13 patients: it was temporal (6 cases), frontal (4 cases), occipital (2 cases), parietal (1 case). The topography was cortical in 2 cases, corticoundercortical in 4 cases and deep in 7 cases. The mean diameter was 1.7 cm (1 cm - 2.5 cm). The postoperatory examination showed that the residual zone of exerese had a diminished volume in comparison to the initial lesion (in 9 cases) or an identical volume (in 2 cases). It presented a hyposignal on Tl-weighted images and a hypersignal on T2-weighted images, more pronounced on the second echo (same signal that CSF). In 2 cases the surgical resection had involved the front part of the temporal lobe. 10 cases presented a peripheric residual zone of signal loss similar to the preoperative aspect (9 cases) or increased ( 1 case). In 6 cases there was a focalized parenchymal hyper signal in the operated lobe on T2-weighted images. There was no correlation between the postop MRI aspect and the clinical symptoms (improvement in 11 cases, statu quo in 1 case, increased number of crisis in 1 case).In conclusion, postoperative MRI examination about one year after surgical treatment of cavernoma shows usually a residual lesion whose signal is similar to CSF, surrounded in the majority of cases by a T2weighted asignal zone corresponding to hemosiderin.

Purpose: To determine the different MR aspects of

temporal lobe malformations, their frequency, and clinical expression in patients with temporal epilepsy of variable severity. Material and Methods: Two hundred consecutive adult patients with partial epilepsy of varying severity were investigated, between January 1991 and May 1993, at 1 tesla until September 1992 and then 1.5 tesla (after upgrading of the system), with the following MR protocol: 1) sagittal Tl-weighted; 2) oblique coronal Tl-weighted, spin echo (at 1 tesla), or TurboFLASH 3DFT (at 1.5 tesla), perpendicular to the long axis of the hippocampus; (3) coronal, T2weighted.Gadolinium (DTPA)-enhancement was performed with the oblique coronal, Tl-weighted protocol. Results: Fourteen patients (7 %) presented malformations of the temporal lobe. Three different patterns of malformations were encountered: (1) complex malformations of the temporal lobe, including heterotopia, cortical dysgenesis, and HF abnormalities (n = 3); (2) focal neocortical dysgenesis (n = 6) involving the parahippocampal and or occipito-temporal gyri, which consisted either in cortical thickening, poor g r e y / w h i t e matter demarcation, abnormal gyration (n = 5) or limited s c h i z e n c e p h a l y (n = 1); (3) h i p p o c a m p a l malformations (n = 5) which presented either as abnormal HF associated to a cyst (n = 2), isolated malformation of the subiculum (n = 1), or bilateral HF malformation (n = 2) consisting in an abnormal shape and a misplaced fimbria. Hippocampal atrophy was found in 5 of the 9 patients with extrahippocampal malformations. The age at onset, the severity of the disease, and the occurrence of generalised t o n i c o - c l o n i c seizures were not significantly different between patients with malformations and the global population of patients with temporal lobe epilepsy. The same pattern of malformation could be associated to intractable as well as to mild form of epilepsy. Preoperative intracerebral-EEG recordings performed in two patients revealed that the site of initiation of the e p i l e p t o g e n i c activity could be either the malformation itself (n = 1) or associated hippocampal pathology (n = 1). C o n c l u s i o n s : Malformations of the temporal lobe were found in 7% of patients with temporal lobe

S 98 POSTERS epilepsy (TLE). The clinical expression of these patients was not significantly different from the global population of patients with TLE. Three-dimensional MR analysis of temporal lobe malformations allowed a precise determination of the extent of the malformations, the presence or absence of associated hippocampal pathology, and guided the placement of intracerebral or subdural electrodes, all of which are of great help in the preoperative evaluation of patients with intractable epilepsy.

P-19 MR I M A G I N G IN EPILEPSY, CORRELATIVE STUDIES Walecki J, Boguslawska R, Krolicki L, Marszalek P Med.Centre of Postgraduate Education, Warsaw, Poland Presentation of own material containing various types of epilepsy, diagnosed by MR and other methods. No. of examined patients : 52 (F-32,M-20). MR was performed with MRT 0,5T(TOSHIBA), CT using EXPERT 1200 (PICKER). EEG and SPECT have been performed with many equipment. In 43 patients (83%) we have found in MR changes associated with epilepsy. In 20 patients examined recently MR was done in first two weeks after epileptic seizure - we have noticed various lesions mainly localised in cortex. MR imaging is a very sensitive method for the detection of seizure foci and lesions accompanying epileptic seizure. Comparison of value of MR, CT and SPECT in the diagnosis of epilepsy and MR findings of status post epileptic seizure will be discussed.

P-20 A SEMIAUTOMATED METHOD TO EVALUATE V A S C U L A R DEMENTIA BY MRI: IMAGING AND N E U R O P S Y C O L O G I C A L CORRELATIONS. Paolillo A, Bastianello S, Gasperini C, Giubilei F, Gragnani A, Bozzao A, Bozzao L. Dipartimento Scienze Neurologiche Universita "La Sapienza" di Roma ViaIe Universitgl 30 Roma Italy P u r p o s e : The aim of this study is to achieve a quantitative evaluation of cerebral atrophy and parenchymal ischemic lesions i n patients with vascular dementia (VD) using a semiautomated method by MRI and to identify possible correlations with neuropsycological impairment. Material and Methods: We studied 40 patients (24 male and 16 female: average age: 71.16 SD + 3.2). with VD diagnoses according to DSM-III parameters. All patients were imaged on a 0.2 T MR unit, T1 and T2 weighted images on axial and sagittal planes were obtained.The volume of supratentorial structures were

P-O1 - P-116 automatically calculated by the work station of the MR unit.The technique involved intensity threshold segmentation in order to isolate first of all brain from surrounding tissue, then to identify parenchymal lesions, ventricles and CSF spaces. The volume of these structures were correlated with total parenchymal volume.The cognitive functions were studied using the following neuropsycological tests: MMSE, ADAS test, DIGIT SPAN, PAROLE DI REY, FIGURE DI REY Results: The relationship between hemispheric lesions and ventricular enlargement was statistically significative (p=0.05). A trend was found between total volume of ischemic lesions and cognitive impairment.No significant correlation was found between the localization of ischemic lesions and impairment of particular cognitive functions. C o n c l u s i o n : Our study represents an objective method to evaluate parenchymal atrophy and total lesion volume in vascular dementia patients. Further works are needed to confirm a possible relationship between total volume of ischemic lesions and cognitive impairment.

P-21 IH MR SPECTROSCOPIC IMAGING OF WHITE MATTER SIGNAL HYPERINTENSITIES (BENIGN, A L Z H E I M E R DISEASE, VASCULAR DEMENTIA AND DEPRESSION) Constans J.M, Meyerhoff D.J, Mac Kay S, Gerson J, Norman D.P, Fein G, Weiner M.W. Magnetic Resonance Unit, DVA Medical Center and University of California, San Francisco Purpose:The aim of this study is to characterize and to compare by proton Magnetic Resonance Spectroscopic imaging (MRSI) metabolic changes seen in White Matter Signal Hyperintensities (WMSH) of patients with Alzheimer disease (AD), vascular dementia (VD) and depression (DEP). A secondary goal is to determine if regional differences existed in aged matched controls and to take account of these when comparing controls to patients. Patients and Method: 11 AD, 8 VD, 6 DEP, 8 elderly subjects, non demented, with "benign" WMSH and 22 controls without significant WMSH (C) were studied by axial T2 imaging and by MRSI at 2T. The spectra were extracted from WMSH and contralateral regions for subjects with WMSH and from 6 regions for controls (c). These spectra were processed and fitted to obtain metabolite percents and ratios (total area of metabolites for NAcetyl Aspartate (NAA), Choline (Cho), Creatine (Cr)). Metabolite means and standard errors were computed. Paired-t-tests were used for regional differences analysis. The end of the statistical analysis is ongoing. R e s u l t s : T h e r e are regional differences for age matched controls. All patients with WMSH show

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decrease of NAA compared to controls. Metabolic changes observed in "benign" WMSH are different then those observed in AD, VD, or DEP WMSH.In addition, among the non "benign" WMSH it seems possible to distinguish AD from VD or DEP. Conclusion:These preliminary results show that it is necessary to compare WMSH with corresponding anatomical regions for controls. The presence of WMSH, their extension, and the metabolite values in WMSH are important covariants in spectroscopic study of cerebral pathologies.

P-22 M R - A N G I O G R A P H Y : A C O M P A R A T I V E CASE S T U D Y B E T W E E N T I M E OF F L I G H T (TOF), PHASE CONTRAST (PC) A N D D I G I T A L S U B T R A C T I O N A N G I O G R A P H Y (DSA).

Eberhardt K.E.W 1, Hollenbach H.P 2 Bottcher U 2, Huk W.J 1 1 Department of Neuroradiology, NeurosurgicaI Clinic, University of Erlangen, Germany2 Siemens AG, Medical Engeneering Group, Erlangen, Germany Purpose: MR-Angiography plays an increasingly important role as an alternative method to conventional angiography. In this case study we compared two MR-methods (TOF and PC) with DSA. Material and Methods: We examined 25 patients with thrombosis of the venous system, arteriovenous malformations and in 5 cases wHh malignant tumors. The investigations were performed using a 1.0 T whole body MR-system (Siemens Magnetom Impact). A 2Dsequential-TOF (TR/TE/a 22/10/35 ms/ms/deg) and 3D-TOF- with Magnetization Transfer-pre-pulse and T O N E - e x c i t a t i o n RF-pulse (TR/TE/a 42/10/20 ms/ms/deg) as well as a 3D-PC-sequence (TR/TE/a 7-/8/15 ms/ms/deg) were applied in sagittal and transverse orientation using a circularily polarised head coil. The velocity encoding of the PC-sequence varied between 10 and 60 cm/sec depending of the blood flow velocity. The highest spatial resolution was 1.04 x 0.78 x 1.00 mm3. The acquired 3D-data sets were evaluated using a Maximum Intensity Projection (MIP) program. The results of MR-Angiography were compared with DSA and intraoperative findings. Results: The sensitivity of TOF and PC is comparable with DSA in the diagnosis of thrombosis of the venous system. In patients with malignant tumors early veins could be seen very well with TOF and PC. MRAngiography may be superior to conventional angiography in cases of giant aneurysms. Conclusion: In special cases, MR-Angiography may be superior to DSA. In the diagnosis of aneurysms DSA has still advantages, especially in small aneurysms.

P-01 - P-116 P-23 N O R M A L V E N O U S A N A T O M Y OF THE BRAIN : DEMONSTRATION WITH A DYNAMIC CONTRAST ENHANCED SUBSTRACTION MAGNETIC RESONANCE ANGIOGRAPHY

Tournut Ph., Douek Ph., Turjman F, Baldy C, Falise B, Froment J. C. Service Radiologie H6pital Neurologique P. Wertheimer, Lyon - France Purpose: The two major forms of magnetic resonance (MR) angiography, time of flight and phase contrast are limited by spin saturation, intra-voxel dephasing, long imaging time. In order to overcome these limitations, we developed a new MR angiography technique combining fast MR imaging, Gadolinium injection and substraction. M a t e r i a l and M e t h o d s : Ten volunteers were e x a m i n e d using segmented K-space F L A S H (SIEMENS 1,5 T, sagittal view, FOV: 25 cm, slices thickness 15 mm, matrix slice 192 x 256).Data were acquired for 80 seconds beginning 20 seconds after intravenous bolus injection of Gd-DOTA (0,1 mmol/Kg) with a power injection (5 ml/sec). On a standard MR console, substraction images were created by substracting pre contrast from post contrast images of the dynamic study. Substraction and maximum intensity projection images were compared with conventional angiograms. Results: Substraction permitted background signal intensity suppression and visualisation of vascular enhancement and demonstrated cerebral venous anatomy. C o n c l u s i o n : This technique is a promising new method for venous anatomy imaging. Although further evaluation is required, clinical indications of this technique may be useful in case of suspicion of clot when methemoglobin has high signal intensity on spin echo and gradient echo images and can be mistaken for flow.

P-24 MR ANGIOGRAPHIC EVALUATION OF INTRACRANIAL BASAL VENOUS CIRCULATION IN A C H O N D R O P L A S I A

Patay. Z.*, Baleriaux, D.*, Van Bogaert, P.**, David, Ph.*, Leproux, F. *, Raftopoutos Ch.***, Szliwowski, H ~.

*Dep. of NeuroradioIogy, **Dep. of Pediatric Neurology, ***Dep. of Neurosurgery Hopital Erasme, Universite Libre de Bruxelles, Brussels, Belgium P u r p o s e : To evaluate the cranial venous outflow by MR angiography in a case of internal and external hydrocephalus of suspected venous origin. Material and Methods: A one year old achondroplastic child presenting with an external and internal hydrocephalus was investigated, in order to

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determine if hydrocephalus was due to CSF circulation or venous outflow disturbances. The brain parenchyma and the cranio-cervical junction was studied by conventional T1 and T2 weighted spin echo MRI sequences. The base of the skull was explored by high resolution computed tomography using 3D reconstruction, as well. The basal intracranial venous circulation was evaluated by 2D Time of Flight and 3D Phase Contrast sequences. 2D Phase Contrast sequences were used to create phase images, in order to determine flow direction in the different venous structures. Results: Complex venous outflow disturbances, due to the proven stenosis of both jugular foramina, were demonstrated by MR angiography. Morphologically and hemodynamically abnormal collateral transcranial emissary venous outflow pathways were detected on both sides at the level of the pterygoid plexuses and the superior ophthalmic veins, respectively. Although it was impossible to directly visualise blood flow inside the jugular veins at the level of the jugular foramina (probably due to high velocity and/or turbulent flow), the variable aspects observed with the different MRA sequences was highly suggestive of a persisting permeability, at least on the left side. C o n c l u s i o n : MR angiography provides valuable information concerning the intracranial venous outflow disturbances in achondroplasia. This way, it can replace conventional angiography in determining surgical therapeutic strategies of hydrocephalus associated to achondroplasia.

P-25 MRI ANGIOGRAPHY BRIGHT A N A L Y S I S OF P A T H O L O G I C A L C E R E B R O V A S C U L A R DISEASE

IMAGES: DATA IN

Liboni W, Rebaudengo N., Davieo M.Presidio Sanitario Gradenigo - C.so R. Margherita, 8, Torino. Arterial Angiography Magnetic Resonance is a proficient non invasive method for imaging both normal and pathologic vascular anatomy of the brain and neck. The pictures provided by AAMR only recall the conventional x-ray angiography being the vessels images flow velocities dependent. As regards ischemia in the cerebrovascular perfusion territory, A A M R r e l i e f depends a l t o g e t h e r on the physiopathologic alterations of the blood velocity caused by the ongoing disease, both related to vessel anomalies and to perfusion pressure variation.The quality of images is strictly correlated with the flow velocity and currently 3D or 2DMS techniques are used conforming with high or low blood velocities range. The Color Velocity Imaging (CV[) and Transcranial Doppler (TCD) programs can optimise the angiographic relief, showing the extra-intracranial velocity's range. In our experience 3D is most useful

when the velocity is more than 40 cm/sec., below this value, 2 DMS is better. Besides, TCD acetazolamide test provides the condition of vasomotor reactivity. If the VMR is exhausted, we cannot optimise the AAMR images, even with the most useful angiographic techniques related to velocities range. In fact, the signal and definition of vessel, distributing into territory with pathological response to acetazolamide test, are poor. This condition assumes blood perfusion alteration meaning and confirms the acetazolamide test results in revealing cerebrovascular disease. The physiopathologic relief by AAMR gives more information by properly using 3D or 2DMS techniques, and by the multiplanar reconstruction, if we have to detect the course of the nerve and vessel in presence of neuralgia or in presence of a loss of sensory function.

P-26 I N T R A C R A N I A L A N D C E R V I C A L L O W FIELD M R A IN C E R E B R O V A S C U L A R ISCHEMIC DISEASE

Dal Pozzo G, Cellerini M, Marin E, Pellicano G Neuroradiology, University of Florence, Italy P u r p o s e : T o assess the utility of low-field 2D-TOF MRA of intracranial and cervical vessels in patients with MRI findings of cerebrovascular ischemic disease. Material and Methods:From January to December 1993, 19 patients (15 M, 4 F, mean age : 64,3 years) with symptoms and signs of cerebrovascular disease (TIAs and stroke syndromes) were retrospectively examined. In all patients the cranial MRI was followed by a 2D-TOF MRA) of intracranial and cervical vessels (0.3T Hitachi 7000). In 4 patients hemodynamic evaluation of the circle of Willis was obtained by means of selective presaturation band technique. R e s u l t s : I n 12 patients conventional cranial MRI showed brain parenchymal lesions consistent with unibilateral watershed lesions (4pts) and/or corticosubcortical infarctions in typical arterial vascular territories (8pts); in 7 patients no parenchymal lesions were detected but MRI was able to depict arterial abnormalities (4 internal carotid artery dissections, 3 internal carotid artery steno-occlusion). MRA showed various degree of uni-bilateral internal carotid artery narrowing in 14 patients; this finding was associated to absent or scant visualisation of vertebral arteries in 3 patients; furthermore MRA demonstrated an abrupt stop of the posterior occipital artery in 2 patients with occipital arterial cortico-subcortical infarction. In 3 patients with small multiple subcortical ischemic foci MRA was negative. In all but one patient ischemic lesions corresponded to the side and degree of the arterial stenosis. Selective presaturation bands technique allowed demonstration of "subclavian artery

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steal syndrome" in 1 patient and of collateral supply by means of the circle of Willis in 3 patients. Conclusions:Intracranial and cervical low-field 2DTOF MRA seems to be an useful complementary tool in patients with MRI findings of cerebrovascular ischemic disease. It allows not only demonstration of the possible cause of cerebrovascular disease (good correlation between parenchymal lesions and side and degree of arterial s t e n o - o c c l u s i o n ) but also hemodynamic evaluation of the collateral supply improving patient management.

P-27 A C C U R A C Y OF 3-D P H A S E - C O N T R A S T MR ANGIOGRAPHY AT 0.5 TESLA IN EVALUATION OF CERVICAL ARTERIES STENOTIC LESIONS.

Dumas J-L 1, Attali P 1, Azorin J 2, Belin C 3, Salama j 3, Goldlust D 1 Departments of Radiology 1, Thoracic and Vascular Surgery 2, Neurology 3, H6pital Avicenne, Bobigny, France. P u r p o s e : To determine the accuracy of threedimensional phase-contrast MR angiography in evaluation of cervical arteries atherosclerosis. Material and Methods: In 10 patients (mean age 70y, 2 with cerebral infarction, 5 with transient ischemic attacks, 3 without cerebrovascular disease) MRA was carried out with a 3-D phase-contrast technique by using a GE Vectra 0.5-T imager with a coronal acquisition localised on the skull base arteries with a head coil (slab thickness of 60 mm, FOV of 20 cm, Venc of 20 cm/s, flow encoding 3 axes). Results were correlated with x-ray angiography (XRA) (n=2), doppler ultrasound (US) (n=2) or both (n=6). Upon XRA or US findings 4 vertebral and 14 carotid stenoocclusive lesions were classified as occluded, severely stenotic (with hemodynamic effects) or moderately stenotic (without hemodynamic effects). Results: In cases of occlusion (n=6) MRA showed a disappearance of flow signal in the affected artery. In 7 out of 9 severe stenoses M R A displayed a decreased flow signal in the distal segment of the artery. In cases of moderate stenosis (n=3) the distal flow signal was judged as normal. In case of bilateral carotid artery stenosis (n=4) M R A displayed an asymmetric flow signal loss depicting the side of the greatest stenosis. Mean p e r c e n t a g e a g r e e m e n t between MRA and XRA was 93% and between MRA and US was 71%. Morphologic delineation of the stenotic lesion was weak in all the cases. C o n c l u s i o n : Phase contrast-MRA can discriminate hemodynamically significant stenoses and differentiate them from total occlusion. It appears useful as the primary non invasive diagnostic tool for evaluating patients with suspected cervical stenoocclusive lesions with potential surgical indications.

P-01 - P-116 P-28 MRA IN DIAGNOSTIC OF SPACE OCCUPYING LESIONS WITH AFFECTION OF SINUSES AND C E R E B R A L VEINS

Orszagh M., Schumacher M., Scheremet R. Section of Neuroradiology, University of Freiburg, Freiburg, Germany Purpose: 15 patients with meningiomas, abscesses and other space occupying lesions in the proximity of the cerebral sinuses and large veins have been investigated in order to evaluate MR-angiography in delineation obstruction or infiltration of venous structures as well as collateral venous pathways. Material and Methods: 9 meningiomas and 6 other space occupying processes were studied pre- and postoperatively by MRA and selective arterial DSA. In MRA we used high- and slow-flow-sensitive gradient-echo-sequences with 2- and 3-dimensional MIP-reconstructions before and after administration of Gd-DTPA Results: In nearly all cases we could precisely decide by the MRA-studies, whether the sinuses were impressed, infiltrated or even occluded, which was finally confirmed during surgery. H o w e v e r the auxiliary drainage could not be depicted by MRA as clearly as by DSA. Conclusion: MRA is a major progress in the preoperative management in patients with lesions close to the cerebral sinuses and supports neurosurgeons in planning the appropriate surgical strategy, especially to assess if a incomplete or total resection can be expected. The anatomical details regarding compression, obstruction or infiltration could be better analysed by MRA. However functional parameters as collateral drainage and hemodynamics were more clearly demonstrated by DSA.

P-29 CLINICAL APPLICATION OF ARTERIAL BLOOD FLOW VELOCITY MEASUREMENTS USING DOPPLER TIPPED GUIDEWIRES

Benndorf G., Podrabsky P, Borschel M, Biamino G, Fleck W, Lanksch W, Felix R. Rudolf-Virchow-Hospital, Free University of Berlin, Germany. Purpose:Evaluation of intraluminal measurements of arterial blood flow velocity during interventional procedures in patients with different cerebrovascular diseases. Material and Methods:The blood flow velocity was measured in eleven patients undergoing selective or superselective angiography of supraaortic and cerebral arteries during diagnostic or interventional procedures: Five patients with angioplasty of supraaortic vessels, two patients with thrombolysis and four with embolisation of cerebral arteriovenous malformations (AVM) were examined. All measurements were

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POSTERS p e r f o r m e d before and after the interventional procedure with a Doppler-Tipped Guide wire of 0.014" and 0.018 " Results:The increase of velocity could be measured immediately during and after the angioplasty (e.g. 14/33 cm/sec in the vertebral artery). Significant improvement of flow was recognized (e.g. 20/50 cm/sec) after thrombolysis of occluded basilar arteries. After endovascular treatment of cerebral AVM the reduction of flow velocity (e.g. 142/52 cmlsec) was observed. C o n c l u s i o n : E v a l u a t i o n of blood flow velocity in patients with different 1 cerebrovascular diseases u n d e r g o i n g interventional p r o c e d u r e s can be performed accurately and provide valuable functional information to complete the angiography. It gives immediately hemodynamic data after endovascular treatment of cerebral AVM, which is important especially in partial treatment. During thrombolysis or angioplasty it permits a continuous monitoring and supports the decision of finishing the procedure if satisfactory improvement of flow is achieved. On going studies should further estimate the value of performing this technique. P-30 3D VOLUME RENDING I N T R A C R A N I A L VESSELS

FORMRA

OF

Maeder p.p1, Meuli R.A 1, Aroua A 2, de Tribolet N 3, Schnyder p1 Departments of Radiology 1 and Neurosurgery 3, CHUV, Lausanne, Switzerland.Institute for Applied Radiophysics 2, Lausanne, Switzerland. Maximal intensity projection (MIP) is the generally used technique for 3D projective representation of MRA. This robust technique with low computational power requirement suffers a lack of realism. This work presents a new approach for 3D rendering of MRA using a volume computational technique. MRA were obtained at 1.5 T on a Magnetom 4000 SP and transferred by network on a Silicon Graphics 31 ONGX computer were T1 volume rendering software Voxel View was used. This software processes the entire data set into a 3D object with transparency, colours and lighting properties. Stereoscopic vision is also available with the use polarised glasses. This rendering technique was applied to 14 selected MRA of intracranial vessels with obstructive disease or saccular aneurysm. By comparison to MIP two independent observers judged the length and the continuity of the vessels and gave a subjective appreciation of the quality of the 3D representation of the pathology. 3D volume rendering gave a much better subjective representation of the pathology especially with stereoscopic vision without improvement of the length or continuity of the vessels. Selected cases will be presented.

P-31 ACETAZOLAMIDE-ENHANCED MR ANGIOG R A P H Y OF C E R E B R A L A N E U R Y S M S

Tsuchiya K, Mizutani Y, Seki T, Hachiya J, Furuya Y. Department of Radiology, Kyorin University, Tolcyo, Japan WITHDRAWN

P-32 TRANSIENT INNER EAR DYSFUNCTION FOLLOWING ENDOVASCULAR OCCLUSION OF T H E L O W E R SIGMOID SINUS: AN ETHIOPATHOGENIC HYPOTHESIS

Roy D., Lavigne F., Raymond J. Hopital Notre-Dame, Universit~ de Montreal, Montreal, Canada P u r p o s e : The treatment of dural fistulas of the sigmoid sinus may require endovascular occlusion of the involved sinus. We identified 2 cases of transient cochleo-vestibular abnormalities proved at audiometry and ENG. The purpose of this paper is to explain the physio-pathology of this phenomenon. M a t e r i a l and M e t h o d s : The clinical evolution, audiology and vestibular evaluation of our 2 patients were reviewed. Anatomical considerations according to the venous drainage of the inner ear as well as endolymphatic apparatus are presented. Results: One of the patients presented only with vestibular dysfunction whereas the other one showed both cochlear and vestibular signs. In both cases, the process was entirely reversible in less than 10 days after steroids and betahistidine were administrated. Conclusion: According to earlier experimental works on ligation of the cochlear veins leading to permanent damage, we propose a transient impairment of the endolymphatic metabolism due to the proximity of the saccus endolymphaticus with the lower sigmoid sinus as the mechanism of the transient symptomatology affecting these patients. P-33 PRE AND POST EMBOLISATION MANAGEMENT U S I N G ANGLO M R W I T H P A T I E N T S W I T H B R A I N AVMs T R E A T E D BY E N D O - V A S C U L A R ROUTE.

Tournade A., Krupa P, Tajahmady T, OesterIe H, Stilhart B, Coscia S, Srour R, Cerfon J.F, Courtheoux P. Interventional Neuro-Radiology and Neuro-Surgery, H6pital Pasteur Colmar France. Purpose : The goal of our study is to demonstrate the potential advantage of AngioMR in the evaluation and the follow up of the patients with brain AVMs treated by endovascular route. Material and Methods : Four patients underwent our data from July 1992 to December - Angiography was p e r f o r m e d in super selective way authorising

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embolisation of the nidus with its feeders. - In all cases, AngioMR was performed with time of flight technic using pre saturation slabs. The analysis of the MR angiograms was performed using selective saturation in order to emphasise, both and separately, the arterial feeders, the nidus and the venous drainage of the AVMs. With the increasing experience of our team, all these factors were a n a l y s e d in good conditions, thus a v o i d i n g angiography in the routine follow up. AngioMR is a very good way to evaluate the efficacy of the embolisation in the routine follow up of AVMs. - AngioMR is a safe, easy, in a very good economic condition and reproducible data with outpatients, thus allowing us to reserve angiography for therapeutic phases of the management.

P-34 EVALUATION OF SUPER SELECTIVE EMBOLIZATION OF CEREBRAL ARTERIOVENOUS MALFORMATIONS BY T R A N S C R A N I A L DOPPLER SONOGRAPHY

Dorfmuller 1, Brassell F. 2, Sollmann W.P 1, Hussein S 1 , Becker H 2 Departments of ] Neurosurgery and 2 Neuroradiology, Medizinische Hoehschule Hannover, Hannover, Germany Purpose: During e m b o l i z a t i o n of c e r e b r a l a r t e r i o v e n o u s m a l f o r m a t i o n s (AVM), digital substraction angiography (DSA) primarily demonstrates a normalization of the arterial filling with little or no reduction in the nidus. In order to achieve additional information on the altered hemodynamics, we performed transcranial Doppler sonography (TCD) before and sequentially after single or staged embolizations. Material a n d M e t h o d s : 24 patients with an intracranial supratentorial AVM underwent 44 embolizations with Ethibloc. They where studied before, within 24 hours after and within one week after each embolization by means of TCD and the findings were compared with the corresponding DSA. R e s u l t s : Flow velocities (FV) in the main feeder decreased and their pulsatility index (P.I.) increased substantially within the first 24 h after each embolization. During the following week, FV did not change, while a significant decrease of the P1.. was observed. In general, there was a good correlation of the TCD findings with the angiographic effect of the treatment. The hemodynamic alterations were only moderate following the first embolization, while further staged e m b o l i z a t i o n s or a c o m p l e t e obliteration led to a normalization of the Doppler frequency spectra, Of 6 patients with an inter hemispheric steal, redistribution of flow direction and velocities during the course of treatment were achieved in all but one. In single cases, TCD

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indicated feeder r e c r u i t m e n t after i n c o m p l e t e embolization in later follow-up examinations. C o n c l u s i o n : While DSA remains the diagnostic standard for the assessment of the volume and flow patterns of an embolized cerebral AVM, we found a good correlation of TCD with the corresponding DSA. Being able to demonstrate even slight hemodynamic alterations in the basal cerebral arteries during the course of staged embolization, TCD can be, in our opinion, an aid in evaluating the treatment effect.

P-35 AN EURISTIC A P P R O A C H TO AVMs V O L U M E RECONSTRUCTION FROM BIPLANE ANGIOGRAPHY

Foroni R, Piovan E, Zampieri P, Gerosa M.A, Pasqualin A, Perini, Pasoli A. Dipartimento di Neurochirurgia - Ospedale Civile Maggiore - Verona - Italy Three dimensional (3D) volume reconstruction is easily feasible with axial, coronal or sagittal CT and NMR scans. On the other hand, Arteriovenous Malformations (AVMs) are well defined with angiographic procedures, those are based on two orthogonal projections. As a consequence it may be troublesome trying to achieve informations concerning the volume and shape of an objet with only two orthogonal projections. Most commonly AVM volumes have been calculated by assimilating the nidus volume to a prolate ellipsoid. Such a technique may increase the error margin in the evaluation of complex shapes. At the Neurosurgical Department of the University of Verona we recently developed an algorithm dedicated to 3D structure reconstruction starting from two stereotactic orthogonal projections. This has been achieved using an heuristic approach which was widely been adopted in the Artificial Intelligence domain: its postulates concern the definition of the shape and the silhouette of the profiles of each projection. Tests on phantom of different complexity have shown excellent results, thus enhancing the capability of the algorithm to create 3D shapes as close as possible to reality. The importance of the algorithm is considerable, as matter of fact: 1) it allows calculations of complex structures far away from regular prolate ellipsoid; 2) it provides visualisation on axial, sagittal or coronal planes; 3) it is really handy and can be implemented on any computer platform; 4) the execution time is faster (less than 1 minute).Volumetric analyses over 30 patients have shown not negligible discrepancies between volumes calculated with the ellipsoidal model and with this new algorithm: differences that in several cases appear to be quite relevant.

S 104 POSTERS P-36 C T - S U B T R A C T I O N A N G I O G R A P H Y A N D XEENHANCED CT FOR DIAGNOSTIC MANAGEMENT OF INTRACRANIAL ARTERIOVENOUS MALFORMATIONS BEFORE AND AFTER R A D I O S U R G E R Y

GOrzer H., Nasel CO, Schindler E. Department of Neuroradiology, University Hospital, Vienna, Austria. P u r p o s e : CT-subtraction angiography (CTA) was used for diagnosis and radio surgical planning (gamma-knife treatment) in patients with intracranial arteriovenous malformations (AVM). CTA was carried out, after radiosurgery, as well, for follow-up and for evaluation of the CTA-guided treatment results. XeCT with quantitative rCBF measurements was carried out for evaluating the effect of the AVM on the rCBF of the surrounding brain tissue. The alteration of the rCBF after radiosurgery was analysed in comparison to the pre therapeutic findings. Material and Methods: 15 patients with intracranial AVM were examined with CTA and Xe-CT. This examinations were carried out before and a few days after radiosurgery, and - for evaluating the treatment effect - 6 months later. CTA was done with a S o m a t o m Plus S ( S i e m e n s ) ; C T - s u b t r a c t i o n a n g i o g r a p h y was a c h i e v e d by c o m p u t e r i s e d subtraction of the plain CT from the analogous enhanced CT. Maximum intensity protection was applied for visualising the vessels. For Xe-CT, an optimised 3 minutes wash in and 3 minutes wash out protocol was applied, and measurements based on four CT-slices were done. The Xe concentration was 30 %. R e s u l t s : CTA proved to be a valuable tool for planning radiosurgery of AVM. Based on CTA, an exact stereotactic treatment planning was possible. The advantage of this modality could be ascertained, since an early irradiation effect (AVM-occlusion) could be shown with CTA shortly after radiosurgery. Furthermore, a good correlation of morphological and functional changes could be assessed with comparing CTA and Xe-CT. C o n c l u s i o n : The combination of CTA and Xe-CT is very useful for the diagnostic management and the radio surgical planning in intracranial AVM. CTA and Xe-CT also provide with significant information about the treatment effect after radiosurgery.

P-O1 - P-116 P-37 EMBOLIZATION OF ARTERIOVENOUS M A L F O R M A T I O N - A 12 YEAR EXPERIENCE

Gupta A.K., Rao V.R.K, Ravimandalam R, Joseph S, Unni M, Rao A.S Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India. Purpose: To study the effect of endovascular therapy in m a n a g e m e n t of c e r e b r a l arteriovenous malformation Materials a n d M e t h o d s : In 75 patients, 120 endovascular procedures were performed. Majority of patients presented with history of seizures or subarachnoid haemorrhage. Obliteration of the nidus was attempted using IBCA or NBCA, hydrogel, lyophilised duramater, autologous muscle and detachable balloons. R e s u l t s : Angiographic cure was obtained in 16 patients (21%). Five patients with malformation of the aneurysm of vein of galen were embolized and angiographic cure was achieved in 4. Transient neurological deficit was noted in 7(9%) and severe deficit recovering slowly in another 4 (5%) Four patients died due to procedure related complication

(5%). Conclusion: The goal of embolization is to selectively obliterate the nidus while preserving the adjacent normal circulation. O u t c o m e of the angiographic obliteration was favourable if the arteriovenous malformation was supplied by one or two arterial pedicles. There was no definite relation between the degree of obliteration and size of the arteriovenous malformation and the size or the number of feeding arteries. AVMs completely curable by embolisation should be treated by endovascular approach. All resectable AVMs should be embolized preoperatively. The benefits, risks, expected results and natural cause of the untreated arteriovenous malformation must be taken into account while deciding on the choice of endovascular management.

P-38 PRESURGICAL EMBOLIZATION OF INTRACRANIAL MENINGIOMAS: OPERATIVE RESULTS AND HISTOPATHOLOGIC ANALYSIS.

Meder F, Mourey-Gerosa I, Fallet-Bianco C, Roux F.X, Laurent A, Ricolfi F, Frddy D. Centre Hospitalier Sainte Anne, Paris, France. Purpose : In order to evaluate the efficacy of presurgical embolization of intracranial meningiomas with particles, histopathological studies were correlate to radiological and operative findings. M a t e r i a l a n d M e t h o d s : 23 meningiomas of the cranial vault were e m b o l i z e d with particles:

S 105 POSTERS

lyophilised dura mater in 2 cases, polyvinyl alcohol (150-300 ram) in 19 cases and trisacryl gelatine microspheres (200-400 mm) in 2 cases. Superselective embolization was performed in 1 8 cases. Embolization was judged: total in 7 cases (meningiomas supplied solely by the external carotid artery); and subtotal in 16 cases (meningiomas with mixed external-internal carotid arterial supply). Results : Surgical removal without significant blood loss was possible in all cases of c o m p l e t e embolization and in 8 cases of subtotal embolization. Particles of polyvinyl alcohol were observed within the arterial vessels in 15 cases: within the peripheral tumoral vessels in 13 cases and within the centrotumoral vessels in 2 cases. Small areas of tumoral necrosis, of less than 1 centimetre, were observed in 17 cases. Huge areas of tumoral necrosis were observed only in cases of embolization with microspheres. C o n c l u s i o n : This study confirms the good results with possible surgical removal after embolization with particles. However, this analysis also shows the limits of the polyedric embolic materials.

P-39 ENDOVASCULAR TREATMENT OF POSTERIOR CIRCULATION ANEURYSMS. INDICATIONS AND PROBLEMS.

Perini S, Pasqualin A*, Scienza R*, Rosta L, Alessandrini F, Benati A Department of Neuroradiology and Neurosurgery* City Hospital Verona - Italy Recent techniques of selective aneurysmal sac occlusion have markedly improved the indication to endovascular treatment of posterior circulation aneurysms, whiIe balloon occlusion of the parent vessel is still successfully performed, mainly for giant and large neck aneurysms. The aim of this report is to evaluate the indications for treatment and the problems posed by endovascular procedures. From 1992 to date, 16 aneurysms of the posterior circulation were treated. In 5 of them occlusion of the parent vessel was obtained for giant aneurysms at the basilar tip (2), at the PICA origin (1) and in 2 serpentine fusiform giant vertebro-basilar aneurysms. The remaining 11 cases were treated selectively with Target GDC coils according to the FDA (U.S.A.) international trial. Six of them were at the basilar tip, 3 at the PCA and SCA origin and 2 at the vertebral junction. Each case was controlled by MRI and angiography during a follow-up period ranging from 3 months to 3 years. As regards parent vessel occlusion of giant aneurysms a complete clinical cure was obtained in 1 patient only; 1 patient was improved while 3 patients were unchanged. At follow-up studies, signs of intraa n e u r y s m a l t h r o m b o s i s were o b s e r v e d in the

P-01 - P-116

aneurysms with a single parent vessel. No sign of thrombosis or size reduction was observed in the 2 patients with a giant basilar tip aneurysm where 1 vertebral artery was occluded. As regards selective intra aneurysmal occlusion with GDC, it was complete in 9 cases. Follow-up ranged from 2 months to 1 year. No new introduction of coil was needed. In one case selective occlusion of the aneurysm at vertebral junction was problematic in presence of a large neck. No complication occurred but the occlusion of 1 vertebral artery was needed. A major complication occurred in the other patient with a vertebro-basilar junction aneurysm in whom rupture of aneurysmal wall and consequent SAH occurred: the sac was however promptly occluded. Six months later aneurysmal sac is still occluded, patient is alert but presents severe disability. Selective obliteration of aneurysmal sac represents the therapy of choice for basilar tip and other small neck aneurysms of posterior circulation. Those situated at vertebral junction in our series were more problematic. In such cases, occlusion of the parent vessel may be always considered when direct obliteration seems dangerous. Parent vessel occlusion for giant aneurysms is often satisfactory. A careful angiographic evaluation of the circle of Wills and a well neurologically monitored occlusion test is always needed in particular when both v. arteries have to be occluded.

P-40 GIANT ANEURYSM OF THE MIDDLE CEREBRAL ARTERY: INTRA-CRANIAL BALLOON TEST OCCLUSION.

Beaujeux R., Kehrli P, Mangold L, Zollner G, Ribeiro J, Maitrot D, Bourjat P. Department of Radiology A, H6pital Central, Department of Neurosurgery, H@ital de Hautepierre, H@itaux Universitaires de Strasbourg, Strasbourg, France. P u r p o s e : To stress the advantages of intra-cranial balloon test occlusion in the case of giant aneurysm of the middle cerebral artery which is potentially lethal lesion with high per-operative complication rate. Material and Methods: A 16-year-old girl was admitted for subarachnoid and intraventricular haemorrhage due to rupture of a giant aneurysm (4 cm) of the left middle cerebral artery. Clinical status was aphasia, somnolent and right facial palsy. A balloon test occlusion was performed with a L2 balloon mounted with glue on a Magic STD catheter (Balt, Montmorency, France). The balloon was placed first into the aneurysm, inflated and withdrawn as close as possible to the neck of the aneurysm to clarify the temporal branches localization. Next the balloon was deflated and withdrawn into the left

S 106 P-01 - P-116

POSTERS

cerebral artery M1 segment and inflated. The p r o c e d u r e was p e r f o r m e d under clinical and angiographic control. Results: Balloon test occlusion was possible. The first step of the test occlusion allowed us to precisely visualise the neck of the aneurysm and the origin of a temporal artery from the aneurysm itself. For the second step of the test the greatest difficulty was to maintain a perfect stability of the inflated balloon in the neck of the aneurysm. Successive control a n g i o g r a m s h o w e d a too l i m i t e d v a s c u l a r r e v a s c u l a r i s a t i o n through the l e p t o - m e n i n g e a l anastomosis. After 7 minutes the patient got worse ( c o m p l e t e aphasia, h e m i p l e g i a , c o n s c i o u s n e s s alteration). The test was then stopped and total recovery occurred. These vascular features allowed the surgeon to modify the initial surgical plan and to better expose and occlude the neck. After surgery the patient developed partially regressive hemiparesis and aphasia. At the 4 month control she walked with a right hand motor deficit and presented a slight aphasia. Conclusion: Intra-cranial test occlusion is an interesting technique for showing anastomosis possibilities and to precisely determine the vascular anatomy in order to plan the surgery better.

P-41 LOCALIZED

BASILAR ARTERY AGENESIS C O M P L I C A T E D BY D I S S E C T I N G A N E U R Y S M CASE REPORT Ricolfi F. *, Gaston A. *, Decq P**, Combes C* Melon E***Brugieres P* Sadik J.C* Department of Neuroradiology (*), Neurosurgery(**),Anesthesiology( * **) Henri Mondor Hospital Crdteil France Case r e p o r t : A 41 year old male without previous k n o w n p a t h o l o g y was admitted after severe subarachnoid haemorrhage. Angiogram disclosed a dissecting aneurysm of the distal part of the basilar artery. The middle part of this vessel was agenesic distal to the origin of the AICA. according to the data of angiogram and MRI. Selective exclusion of the aneurysmal pouch was considered to be hazardous due to the lack of aneurysmal neck. Then, exclusion of the flow coming from both posterior communicating arteries was performed in order to lower the pressure within the aneurysmal lumen. Occlusion was performed in two stages, successively a surgical clipping of the left posterior communicating artery and a balloon occlusion of the left internal carotid artery at the level of the origin of the posterior c o m m u n i c a t i n g artery. Preocclusion evaluation included prolonged clinical testing, opacification of vertebral arteries, contralateral carotid arteries and somesthesic, auditory and visual evocated potentials recording. Vascular occlusions were well tolerated

and the leptomeningeal anastomotic network of the arteries of the cerebellar surface allowed retrograde filling of the distal basilar artery. Post operative course was uneventful with a 3 weeks anticoagulation therapy. One year follow-up angiogram showed aneurysmal thrombosis with patency of the posterior aspect of the basilar artery. Discussion : Embryological basis of this rare lesion is discussed. The authors point out the high potentiality of arterial anastomosis of the cerebellar surface. Vascular territories supplied by the posterior c o m m u n i c a t i n g arteries are described. These anatomical basis are necessary to discuss flow interruption modalities.

P-42

ENDOVASCULAR TREATMENT OF V E R T E B R A L FISTULAS. Fiore D.L., Sabattini L. o, Roseano P. oo, and Amist~ P. Department of Neuroradiology - Padua; Department of Neuroradiology ~176 Bologna; Department of Radiology ~176 - Padua ITALY. :Vertebral Fistulas are sustained by anomalous communication between vertebral artery and neck veins. The aim of this cooperative study (Padua, Bologna) is to evaluate the efficacy of the endovascular treatment in this pathology. Mostly of the vertebral fistulas are traumatic;the others can be congenital or spontaneous associated with vessel wall alterations like aneurysms and pseudo aneurysms linked with Fibromuscular Dysplasia (FMD) or Neurofibromatosis (NF). Material and M e t h o d s :The Authors report 6 cases of Vertebral Fistulas: 5 Fistulas were spontaneous, 1 was post traumatic. Results :Selective angiography and embolization was performed with femoral approach in 5 cases using detachable balloons. Surgical approach was performed in 1 case. In 3 cases embolized the Fistula was occluded with preservation of the vertebral artery ; in 2 cases the vertebral artery was occluded. Conclusion :The treatment approach for the Vertebral Fistulas was detachable balloons embolization. The innovative advances in the materials (Catheter systems, Balloons, Coils) make the embolization the treatment of choice for this pathology. Purpose

P-43 HEAD

AND

NECK

VASCULAR

MALFORMATIONS Sabattini L. Ospedale Bellaria, Bologna, Italy Head and neck arterious and venous (miscellaneous) malformations propose a lot of problems concerning the radiological diagnosis and the endovascular and/or

S 107 POSTERS surgical therapy. Previous arterial ligatures may seriously limit the possibilities of endovascular approach. Our presentation concerns a group of 12 patients, 3 of them with previous ligatures of afferent arteries: 6 Arterio-venous angiomas 2 deceased 1 malignant ev. 1 liver damage (angiomatosis) 2 in poor clinical conditions in spite of endovascular and surgical therapy ( 1 with arterial ligature) 1 cured in spite of arterial ligature. 1 probably not treatable because of carotid ligature and coexisting anterior communicating artery aneurysm.1 Neonatal angiomal cured.(Kasabach and Merrit syndrome) 4 Venous angiomas 1 Sinus pericranii (?) 3 improved 1 undergoing treatment improved. This numerically limited group concerns a wide variety of endovascular and neurosurgical, vascular surgical, m a x i l l o - f a c i a l and plastic surgical procedures; however it well illustrates the various difficulties encountered in the management of these patients.

P-44 TRANSCRANIAL DOPPLER (TCD) IN EXPERIMENTAL CEREBRAL VASOSPASM; PRELIMINARY STUDY ON DOG T Civit; Bracard

S; Ducrocq X," Marchal J. C; Pinelli C; Auque J; Hepner H. Department of Neurosurgery; Saint-Julien Hospital; University of Nancy; France. With this preliminary study, the authors want to test the TCD, as a method of diagnostic of the experimental cerebral vasospasm. The authors attempt to induce a cerebral vasospasm on 5 beagle dogs ("double haemorrhage canine model") with two successive, 2 days apart, injections of fresh autogenous venous blood into the cisterna magna. A baseline TCD is realised before any injection and the diagnostic of vasospasm is performed daily from day 4. A baseline and day 8 angiography are systematically performed. Finally, all the dogs are sacrificed and the basilar and middle cerebral arteries are examined by optic microscopy. In each case the DTC was performed and the technique for TCD recording on dog was defined. A standardised depth scanning technique was used to identify the different cerebral arteries, allowing to report their referential flow velocity. In two cases there was a perfect correlation between DTC and angiography. In the first one there was no vasospasm. In the other one there was a vasospasm, moreover, confirmed by the microscopic examination. The DTC seems to be an efficient and non invasive diagnostic method for the experimental cerebral vasospasm on dog, avoiding repetitive angiographies.

P-01 - P-116 P-45 DEGRADATION BEHAVIOUR OF POLY (D,L) LACTIDE MICROSPHERES TAILORED FOR CHEMOEMBOLIZATION

Flandroy P. *, Grandfils Ch. **, Daenen B*, Dondelinger R.F*, Jerome R*** Department of Medical Imaging, University Hospital Sart Tilman, Libge, Belgium.** Department of Macromolecular Chemistry, University of Liege, Belgium. Purpose: To compare the degradation features of two types of polylactide (PLA) microspheres in vitro and in vivo. M a t e r i a l s and Methods: The left kidney of 12 rabbits was embolized: 6 with fast and 6 with slow degradable PLA microspheres. Two samples of PLA microspheres of a different molecular weight have been studied. Two lots, a fast degradable one (10 days in vitro) and a slow degradable one (6 months in vitro) were studied by microscopy and molecular weight analysis after embolization. Histologic and chromatographic studies were performed after 6 hours, 1 day, 3 days, 7 days, 15 days and 20 days. Results: Two important observations arose: the fast degradable particles, were changed in an amorphous structure filling the whole arterial lumen, almost immediately after injection. The slow degradable remained spherical during at least 20 days. Degradation rate in vivo of the 2 types of material was about twice faster compared to observation in vitro. Possible factors are local acidosis, water diffusion and potential esterase activity. The difference of the two models in terms of mechanical occlusion and degradation rate could influence upon their effectiveness in chemoembolization. Conclusion: PLA microspheres, which could be degraded within a determined number of days are interesting for sequential chemoembolization.

P-46 ACCELERATED AGEING OF COILS - STUDY BY ELECTROCORROSION.

Domas L. Laurent A. Merland JJ..LNAT Claude Bernard Research Fund. Facultd de Mddecine Lariboisibre St Louis Paris France WITHDRAWN

S 108 POSTERS P-47 INTRASPINAL H E M A T O M A : N E U R O R A D I O L O G I C A L ASPECTS.

I. Muras, Scuotto a, and Bernini F.P Neuroradiology - Second University of Naples - Italy The Authors present their experience on spinal hemorrhage, which in their opinion appears interesting under various aspects, including the rather poor incidence of this pathology. The personal serie consists on 7 cases of intraspinal hematoma, observed from September 1991 to December 1993 and investigated by means of CT scan and/or MRI: 4 cases of hematomyelia ( 3 traumatic in origin, 1 spontaneous ), 1 case of iatrogenic traumatic subdural hematoma, 1 case of traumatic subarachnoid hematoma, 1 case of epidural spontaneous haemorrhage. Intraspinal hematoma may occur in the epidural, subdural and subarachnoid spaces or in the spinal cord in itself. According to the literature h e m a t o m a confined to- the epidural space is the most common type while the intraspinal bleeding is the most unfrequent. The most common site is the thoracic area, followed by the cervical region whereas- the lumbar segment is the least affected site. Spinal haemorrhages develop from trauma, neoplasm, infection, p r e g n a n c y , v a s c u l a r m a l f o r m a t i o n . Sometimes they can be spontaneous or they can result from anticoagulation therapy, lumbar puncture, spinal anaesthesia, spinal surgery (iatrogenic type) .The Authors outpoint some particular aspects of their serie: -the predominance of intramedullary haemorrhage ( 4 cases out of 7 ), the prevalence of cervical localization in all hemorragic lesions (5 cases out of 7). In all patients CT scan and MRI have provided the means for prompt and definitive diagnosis. Referencesl. Manelfe C . - Raven Press- 19922. Naseem M. et al AJNR 7:1096-1098, 19863. Post M . J. D . AJNR 3: 190- 192, 1982

P-01 - P-116 P-48 P O S T U R E . D E P E N D E N T M O D I F I C A T I O N OF THE L U M B A R P O S T E R I O R E P I D U R A L FAT PAD

Beaujeux R., Zollner G, Wolfram-GabeI R, Bourjat P, Dietemann J.L.Department of Radiology, Institute of Anatomy, H6pital Central, H6pitaux Universitaires de Strasbourg, France. Purpose: To realise a functional study allowing us to determine the posture-dependent morphological modification of posterior epidural fat (PEF) and thecal sac at the lumbar disc level. M a t e r i a l and M e t h o d s : Axial CT scans were performed with 3 mm thick sections every 3 mm from L2 to L5 for 12 patients in extension supine position. After then patients were placed in flexion position of the lumbar spine with long wood edges placed under the upper trunk as well as the legs. All images were photographed twice with appropriate density window in order to delineate soft tissues and osseous structures. We made measurements of bony and soft tissues. Measurements were made at the disc level: antero posterior diameter of the thecal sac and the lumbar bony canal, ligamentous interfacet distance measured at the level of joint space, and the crosssectional area of the PER Results: At extension of the lumbar spine, reduction of the transversal diameter (ligamentous interfacet diameter) occurred. In this condition the PEF e x t e n d e d in anterior direction and b e c a m e compressive on the thecal sac. The antero-posterior diameter of the thecal sac was decreased and the posterior edge of the thecal sac modified. Conclusion: PEF put out of shape the posterior edge of the thecal sac when lumbar lordosis increased. PEF should be thought as one of the potential actors in the conflict between soft tissues, bone and nerve roots.

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POSTERS P-49 EPIDURAL LIPOMATOSIS: MAGNETIC R E S O N A N C E I M A G I N G (MRI) A N D C A U S A L TREATMENT.

Furet D, Doyon D, Grumberg A, Cirille S, Idir.ABC Service de Neuroracliologie, H@ital Bic&re, Facult~ Paris Sud. Le Kremlin BicOtre, France. Purpose: Interest of MRI in the evaluation of epidural fat. Material and Methods: Retrospective study of two cases of epidural lipomatosis examined with MRI. R e s u l t s : The authors report two cases of thoracic lipomatosis, with progressive spinal cord and radicular compression. It was related in one case to a paraneoplastic cushing's syndrome and prolonged steroid therapy for haemorrhagic rectocolitis in the second case. A cancer chemotherapy in the first instance, an interruption of steroid therapy and hypo caloric diet in the second instance led to the regression of epidural lipomatosis at the MRI scan. C o n c l u s i o n : MRI is diagnostic in the both cases. It plays a major role in the evaluation of epidurat fat, especially for the diagnosis of epidural lipomatosis. A causal therapy without laminectomy was successful.

P-50 COMPARISON OF C O N V E N T I O N A L AND H I G H D O S E M R C O N T R A S T M E D I U M IN THE DIFFERENTIAL DIAGNOSIS BETWEEN RECURRENT HERNIATED DISK AND SCAR TISSUE

Dooms G. C, Janssens D. Centre Hospitalier of Luxembourg, Grand-Duchy of Luxembourg P u r p o s e : A prospective study was performed to compare the results of conventional and high dose MR contrast medium in the differential diagnosis between recurrent herniated disk and scar tissue. M a t e r i a l and M e t h o d s : Twenty five patients (20 males and 5 females; mean age: 36 years) were evaluated using conventional (0.1 mmole) dosage of MR contrast medium (sagittal T1 and T2 and transversal T1 weighted images). The same study was repeated one day later with a high dosage (0.3 mmole). R e s u l t s : Diagnosis was correctly modified in 2 patients (scar tissue) after use of high dosage of contrast medium; contrast enhancement was also greater in 10 patients. In the remaining 13 patients, there was no significant difference b e t w e e n conventional and high dose of MR contrast medium. C o n c l u s i o n : In conclusion, it seems that the benefit from using a high dose of MR contrast medium is very limited. However, base upon a limited number of patients, it needs a further extensive study.

P-51 CERVICAL SPONDYLOLYSIS IN F O U R CASES

: CT F I N D I N G S

Romero F.J., Fernandez L, Coscojuela P, Rovira A, Ibarra B Service of Neuroradiology, Hospital General Universitario Vall d'Hebron. Barcelona (Spain). P u r p o s e : Cervical spondylolysis is defined as a cortical cleft between the superior and inferior articular facet of the articular pillar, the cervical equivalent of the pars interarticularis in the lumbar spine. It is a rare condition. Recognition of this disorder and differentiation from traumatic articular pillar fracture is the paramount importance in patients who have had cervical spine trauma. Material and Methods: The present study details the CT findings in four patients and correlation with cervical plain film. The age range between 2-54 years old. Never of the patient have had trauma previously. Results: In each patient only cervical spine level displayed a spondylolytic defects. In two of ours patients had unilateral spondylolysis and in the others two had bilateral spondylolysis. The six cervical vertebra was affected in two cases and C5 in other, and in the remaining case C2. Spine bifida of the involved level was revealed in two cases. Hypoplasia of the ipsilateral pedicle was seen in three cases. C o n c l u s i o n : The radiologic features of cervical spondylolysis are distinctive and the diagnosis can be strongly suspected from plain films. CT confirm the diagnosis. Associated dysplastic changes and spine bifida suggest that the lesion is congenital.

P-52 INTRAMEDULLARY PRIMARY MALIGNANT MELANOMA

De Merlier Y. *, Sahel M*, Zouaoui A *, Deladoeuille M*, Ismail M**, Dormont D*, Marsault C* * Service de Neuro-radiologie** Service de Neurochirurgie Hopital de la Piti6 Paris (France) We report a case of a 38 years old patient with radicular pain in the left C6 dermatoma which suddenly appeared four months ago. This neuralgia was associated with a right pyramidal syndrome. MRI performed before and after contrast medium showed a left paramedial herniated disk at C5-C6 level. Furthermore a right hyper intense intramedullary lesion was discovered on unenhanced Tl-weighted images in the junction between medulla and spinal cord. Cavernous angioma was suspected. The herniated disk was successfully removed. The neuralgia disappeared but the pyramidal syndrome remained. Two months later a black intra medullary tumour was removed. The pathological examination carried out the diagnostic of malignant melanoma. The MRI performed two months later showed only a

S 110 POSTERS scar tissue. The search for another melanoma was negative. Usually, melanotic neoplasms of CNS are metastatic lesions. Primary malignant CNS melanoma is rare and generally arises from the leptomeninges which normally contain widely distributed pigmented cells. Those cells predominate in the ventral parts of the brainstem and spinal cord. To our knowledge we report the first case of primary malignant melanoma as an isolated intramedullary lesion.

P-53 SUCCESSFUL D I F F E R E N T I A L D I A G N O S I S OF AN O D O N T O I D A L T U M O R BY M U L T I P L E MRI SOFT TISSUE S E Q U E N C E ANALYSIS.

Gerard JM 2 and de Witte 0 3 Divano L 1, Delecluse F2, Bouton R 2 From the MRI unit, Chambor ,the department of Neurology, Hopital Ambroise Pare, Mons, BeIgium and the department of Neurosurgery Hopital Erasme, Brussels, Belgium. A case of progressive myelopathy causing tetraplegia was at first attributed to a neoplasic odontoidal tumor by standard radiological, CT, and MR by T1 Spin Echo with contrast enhancement. The correct ,,5~ benign fibro-conjonctival nature of this mass was ultimately determined by the adjunction of other MRI sequences using Turbo T2 Spin Echo and Turbo I n v e r s i o n / R e c o v e r y , and p r o m p t e d successful decompressive surgery. We believe this case shows not only that MRI is indeed the modality of choice in the anatomical study of the craniovertebral junction, but that multiple soft tissue sequence analysis can provide invaluable insight into the etiology of underlying pathological components by tissular structure diagnosis. We strongly r e c o m m e n d the systematic use of multiple MRI sequence analysis in the differential diagnosis of odontoidal lesions.

P-54 ATLANTOODONTOID OSTEOARTHRITIS : APPEARANCE AND PREVALENCE AT COMPUTED TOMOGRAPHY.

Zapletal J*, Hekster R.E.M*, Wilmink J.T**, Straver J.S*** Institution:Departments of Radiology* and Neurology***, Leyenburg, Hospital, s'Gravenhage.Department of Neuroradiology**, University Hospital Maastricht. The Netherlands. P u r p o s e : T o document the under evaluated and u n r e p o r t e d p r e v a l e n c e and r a d i o g r a p h i c of atlantoodontoid (AO) osteoarthritis. Materials and Methods:In 500 consecutive patients referred for CT of the brain or paranasal sinuses at least two axial contiguous slices through the anterior

P-01 - P-116 C1-C2 joint were evaluated. Abnormal morphology was categorised into three groups;a) Osteophytosis, b) Obliteration of the joint space, c)Transverse ligament calcifications. R e s u l t s : N o degenerative abnormalities were found before the 4th decade. In a significant percentage of older individuals some form of degenerative disease was present. The changes showed a roughly linear progression with advancing age. Conclusion:As d e g e n e r a t i v e change at the a t l a n t o o d o n t o i d j o i n t can cause s u b o c c i p i t a l headache, these morphologic abnormalities should be included in the differential diagnosis in older patients with these symptoms.

P-55 P S E U D O - S P O N D Y L O D I S C I T I C MR IMAGE DUE TO P R O L O N G E D BED REST

Divano L, Delecluse F, Cambier J, JGerard JM and Harcourt A. MRI unit, CHAMBOR and the department of Neurology, Hopital Ambroise Pare, Mons, Belgium. P u r p o s e : In contrast to what is generally believed, discal hyper signal on T2-weighted MRI is not pathognomonic of an acute infectious disease. It is, however, a direct representation of the discal water content , which can vary due to external, mechanical factors, as we tried to prove. M a t e r i a l and M e t h o d s : Three successive MR imaging sequences in Turbo T2 and Turbo Inversion/ Recovery sagittal incidences were performed on the same patient : the first after prolonged bed rest, the second after one hour in sitting posture and the third after one hour in supine position. The patient suffered only from severe, diffuse osteoarthritis. Results: These different preimaging patient positions were followed by significant modifications of the intervertebral discal signal in both T2 and IR sequences. The intense T2 and IR hyper signal of the L2 L3 disc, seen at first, disappeared after the patient had sat up for an hour, only to reappear after she had again lay supine for an hour. Conclusion : In both T2-weighted and Inversion/Recovery imaging, the intervertebral discal signal reflects mainly the state of discal hydration, which can change both because of stasis and of hypervascularity. Thus the same discal hyper signal seen in spondylodiscitis can also be seen after a prolonged bed rest has caused discal hydric stasis, with that image retrogressing after the pressure exerted on the disk is increased by sitting up.

S 111 POSTERS

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HYDATIDOSIS C T AND M R I

can be readily identified. Normal anatomy is presented, as well as various types of disk herniation, and spinal stenosis.

Salvado E, Vazquez F, Careddu A, Del Amo M, Pujol T, Berenguer J, Cardenal C, Anguera A , Tomas X , Mercader J M. Hospital Clinic y Provincial de Barcelona - Universidad de Barcelona. Barcelona. Spain.

P-58 3D CT R E C O N S T R U C T I O N IN A CASE OF C O N G E N I T A L A B S E N C E OF A C E R V I C A L SPINE P E D I C L E ,

P-56 COSTAL AND VERTEBRAL WITH SPINAL INVASION: FINDINGS.

To describe CT and MRI features of hydatidic disease (HD) affecting ribs and adjacent dorsal vertebra with. spinal invasion. We present one case of costal and vertebral hydatidosis clinically characteirized by acute paraplegia, suspected radiologically and confirmed after surgical intervention and positive serological examinations. On CT lesion shows destruction of the head and posterior arch of the ribs and also destructive changes of the adjacent dorsal vertebral bodies, the pedicles and part of the neural arch. L i k e w i s e M R I demonstrates the bone destruction, the cystic nature and spinal invasion with extradural location without intramedullary affectation. Spinal hydatidic cysts are rare and in many cases it is clinically important to diagnose accuratly, specially when spinal cord compression is suspected. The CT scans and specifically MRI are the best neuroimaging methods in these cases. Destructive bone lesions with cystic areas of CT and similar changes on MRI in patients native of endemic areas of HD can suggest the diagnosis. While CT shows the bone lesion better, MRI is superior in demonstrating compression of neural structures and showing the exact extent of the disease all along the spine. In our opinion, the use of CT and MRI is complementary in such cases if suspected.

P-57 T H I N - S E C T I O N 3-D V O L U M E S C A N N I N G IN L U M B A R SPINAL M R I M A G I N G .

Wilmink JT, Hofman PAM University Hospital Maastricht, Maastricht, The Netherlands Lack of clear visualisation of cauda equina fibers is still a problem in lumbar spinal MR imaging. This feature is of importance because incidental disk herniations, not compressing nerve roots, are not rare. By using a gradient-echo v o l u m e acquisition technique, 2 - m m overlapping sections can be acquired, providing a high-quality lumbar radiculogram. Rapid stepping through the scanned volume in a cine-loop mode allows individual root fibers to be followed in the sagittal plane of acquisition, as well as in reformatted transverse, coronal, and oblique planes. Sites of root compression

Solvet P., De Merlier Y, Sahel M, Uzan I, Le Bras F, MarsauIt C Service de Neuroradiologie, H@ital de la Pitie, Paris (France) Purpose :The contribution of reformatage and 3D CT reconstruction to evaluate a congenital spine disorder. M a t e r i a l and M e t h o d s :Medical records and radiologic images of a patient with absent C6 right pedicle, an infrequent developmental anomaly is presented (59 cases reported in the literature).Imaging of this patient included plain films, MRI, axial CT with r e f o r m a t a g e and 3D r e c o n s t r u c t i o n . C T examination was performed on GEMS High Speed Advantage. The acquisition was realised with helical mode. The data were transferred to an Advantage Window workstation and then reconstructed into an isotopic 3D volume. Results :The typical radiologic findings which are the false appearance of an enlarged neural foramen owing to the absent of pedicle, the dysplastic and dorsally displaced ipsilateral articular pillar and lamina, the dysplastic ipsilateral transverse process are directly and clearly demonstrated on the 3D view. We also see the hypoplasia of the pedicle at the level above.This method helps to differentiate these anomalies from cervical spondylolysis or facet fracture dislocation. C o n c l u s i o n :Axial CT alone is limited in accessing the full morphology of such malformations, so far we must frequently use tomograms. 3D CT reconstruction seems to increase our ability to recognise and to characterise accurately these anomalies and can avoid misdiagnosis in difficult cases.

P-59 N E W D I A G N O S T I C AND I N T E R V E N T I O N A L A P P R O A C H OF THE P O S T E R I O R L U M B A R PATHOLOGY

Theron J., Guichaoua-Martin A, Huet H. Department of Neuroradiology and lnterventional Radiology, CHU Caen, France P u r p o s e : Injection of steroids in the facet joints is often decided on non specific clinical and radiological signs. Our diagnostic and therapeutic new approach was aimed to ameliorate our knowledge an therapeutic possibilities on this topic.

S 112 POSTERS Material and Methods : Our experience is based on more that 600 facet joint injections with progressive modification of the radiological work up that includes: 1) Plain lateral projections (standing) centred on L5, 2) CT focusing on the relations between the disc, facet joints and ligamentum flavum, 3) MRI using a new projection (T2, slices tangent to the posterior wall of L5) 4) Modified site of injection of steroids, usually in the ligamentum flavum, Results : This new radiological workup used isolated or in the course of an intradisdiscal therapy provides a much better understanding of the functional unit constituted by the disc and the posterior structures. Conclusion : Posterior structures can be morphologically better investigated and treated on patients presenting with a lumbar painful pathology.

P-60 SPINAL BIOPSY GUIDED BY A C O M B I N A T I O N OF CT AND F L U O R O S C O P Y

Gangi A., Kastler B, Taverne F, Klinkert A, Dietemann J.LRadiologie B, H6pitaux Universitaire de Strasbourg P u r p o s e : T h e purpose of this scientific exhibit is to demonstrate the technique, the safety and the usefulness of the combination of CT with a mobil Carm fluoroscopy in spinal biopsy. Material and Methods:The C-arm is positioned in front of the CT gantry. It allows the association of real time 3-D imaging of fluoroscopy with high resolution CT imaging in an axial plane. During the interventions, CT and fluoroscopy are alternated without changing the patient's position. The intervention can begin under fluoroscopic guidance and then be monitored by CT or start under CT guidance followed by fluoroscopic monitoring. The method and the results are described in 55 patients. Results:This technique allows an easy visualisation of the needle tip and the progression of the needle can be followed in three dimensions. In addition, a far more precise instrument placement is possible. Conclusion:The disadvantages of CT guided biopsy of the spine are the monoplane and delayed imaging of CT. Since the needle tip may deviate from the plane, more contiguous CT slices may be required to visualise the entire needle. The intervention is therefore prolonged, tn order to address this issues, we combined CT and fluoroscopy.

P-01 - P-116 P-61 PERCUTANEOUS LASER DISK DEC O M P R E S S I O N GUIDED BY A C O M B I N A T I O N OF F L U O R O S C O P Y AND CT

Gangi A., Kastler B, Klinkert A, Zollner G, Dietemann J.LRadioIogie B, HOpitaux Universitaires de Strasbourg P u r p o s e : P e r c u t a n e o u s Laser Disk Decompression (PLDD) is an effective and useful procedure to treat herniated lumbar disks without sequestrations. In order to increase safety and accuracy we carry out PLDD guided by a simultaneous combination of fluoroscopy and CT. Material and Methods:68 patients with herniated lumbar disks (36 L5/S1, 28 L4/L5 and 4 L3/L4) and radicular pain without sequestration were treated by PLDD. A mobil C-arm was positioned in front of the CT gantry. The 18 Gauge needle was inserted into the disk under fluoroscopy monitoring (specially useful in L5/S 1 level). Laser energy (Nd:YAG) of 1200 to 2000 J was delivered to the nucleus pulposus. After each 200J a control CT scan was performed to appreciate the vaporisation and it's localization Consequently the needle was repositioned. Results:No incident occurred. The overall success rate was 73,5% according to the MacNab criteria. The mean follow-up period was 6 months. Conclusion: The above described combination offers the following advantages: high accuracy of instrument g u i d a n c e ( e s p e c i a l l y L5-S 1 level), direct visualisation of nucleus pulposus vaporisation and reduced risk of annulus fibrosus perforation.

P-62 EMBOLIZATION OF SPINAL DURAL ARTERIOVENOUS FISTULAS WITH NBCA: H O W TO C O N C L U D E TO A C O M P L E T E CURE? I N T E R E S T OF T H E P O S T - E M B O L I S A T I O N CTSCAN.

Cognard C. Pierot L, Miaux Y, Weill A, Martin M, Chiras J.Service de Neuroradiologie Charcot, H6pital de La Salp@tri@re, Paris. France Purpose: A failure of embolization in spinal dural AVFs, due to a pedicular injection not reaching the initial venous compartment have to be immediately discovered to indicate a prompt surgery and avoid clinical deterioration. The purpose of our study is to determine the more reliable mean to assert the complete and definitive cure just after embolization . Material and Methods: 7 patients embolized for a spinal DAVF with perimedullary venous drainage in the Salp6tri~re hospital from November 1991 to N o v e m b e r 1993 have had an immediate postembolization CTscan. The ability to conclude to a complete cure regarding to the presence of NBCA in the initial venous compartment on plain films and on

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jointive axial images just after injection have been compared to the control angiogram. Results : In 1 patient the embolization failed. The two months after treatment control angiogram showed recurrence of the fistula. The 6 others, had a complete cure with normal control angiogram in 5 cases and in 1 a spectacular and durable clinical improvement. Just after the injection of NBCA, we were not able to know if the glue had reached or not the draining vein in 6 of the 7 cases. In only 1 case, the cast of NBCA on the immediate plain films allowed to conclude to a complete cure. The postembolisation CTscan showed various patterns. In 2 cured patients, the glue was visible in the inner part of the dura-mater and therefore on the venous side. In 5 cases, the glue was approaching the dura around the cord or seemed to reach its surface. It was not possible to determine in those cases the inner or outer dura-mater location of NBCA. In 4 cases, the control angiogram one month to one later was normal. The location of the glue was identical in this five patients and even retrospectively we were not able to differentiate the 4 patients cured from the one not. C o n c l u s i o n : The control angiogram at distance is actually the only way to confirm the durable cure. We suggest that post-embolization CTscan may be a new tool to control the efficiency of the cure. Nevertheless, a more important serie is required to explain the various patterns encountered in the cast of NBCA location on CTscan and to confirm the reliable value of the height of glue.

P-63

QUALITY CRITERIA DEVELOPMENT IN DIAGNOSTIC RADIOLOGY Leonardi M., Maccia C, Moores B.M, Oestmann J.W, Saute D, Walt B, ShibilIa H. Study Group on Quality Criteria Development Radiation Protection Research Action, Commission of the European Communities. Bruxelles. This report presents and analyzes the results of the CEC image quality criteria Trial carried out in 1991 within the framework of the Radiation Protection research p r o g r a m m e of the Commission of the European Communities. The trial was designed to examine the CEC guidelines set for radiographic technique, patient dose and image quality. The results show that the set of criteria defined for evaluating the quality of diagnostic films for lumbar spine, breast and chest examinations can be applied consistently by both field radiologists and international experts. As in many previous studies this trial has shown that patient dose varies markedly for all projection types, and in particular for the lumbar spine projections. However, more than fifty percent of hospital mean doses by projection respect the CEC reference dose value. No

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statistically significant correlation was found between patient dose and image quality.

P-64

CRANIOSYNOSTOSIS : 3D SPIRAL CT EVALUATION Tartaro A., Samuele F, Delli Pizzi C, Di Rocco C*, Colosimo C**Instituto di Scienze Radiologiche Universith "G. d ' A n n u n z i o " - Chieti*Instituto di Neurochirurgia - Sez. Autonoma di Neurochirurgia Infantile - UCSC - Roma **Istituto di Radiologia - UCSC - Roma Spiral CT technique provides rapid acquisitions of large anatomic volumes reducing radiation dosages to the patients; axial slices, multiplanar and three-dimensional (3D) reformations, obtained from the acquired volume, may be reconstructed by means of adequate selection of FOVs and algorithms. The aim of this work was to evaluate the useful of Spiral CT images in diagnosis of the craniosynostosis M a t e r i a l s and M e t h o d s : Eighteen children affected by craniosynostosis were prospectively examined. Spiral CT was performed with 5 m m slice thickness, table feed 5 mm/sec, 165 mAs, acquisition time 24 sec, increment 2 mm. The 3D images, obtained with Surface Redering Technique, were performed with standard and oblique views, using a threshold of 140 UH. All patients affected by craniosynostosis underwent surgery. R e s u l t s : In all patients Spiral CT studies were obtained without anaesthesia or sedation and resulted in good quality diagnostic depiction of both craniofacial anomalies and associated intracranial pathology. Imaging technique and various planes for better visualisation of each sutural abnormality were discussed in detail. C o n c l u s i o n : We conclude that craniosynostosis in paediatric population represent specific indication for Spiral CT study and we emphasise the role of routinely 3D Spiral reformations in the contest of surgical management. Purpose:

P-65

N O R M A L CT A N A T O M Y O F T H E M I N O R FONTANELLES Silbergleit R, M.D., Spickler E.M, M.D. Henry Ford Hospital, Detroit, Michigan, U.S.A. P u r p o s e : To demonstrate the normal CT appearance

of the anterolateral (sphenoidal) and posterolateral (mastoid) fontanelles during the first six months of life. M a t e r i a l s a n d M e t h o d s : 112 CT scans in 107 patients from birth to six months of age were reviewed. Patients with a history of trauma, neoplasm,

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or congenital CNS anomaly were excluded. CT scans were evaluated to determine which fontanelles were open and for unusual appearance of the fontanelles. All patients had at least six months clinical follow-up. Results: At birth and through the first month of life, both anterolateral and posterolateral fontanelles are patent in all patients. There is a steady decrease in sutural patency from the second through six month of life. During the sixth month only t8% of anterolateral fontanelles and 9% of posterolateral fontanelles are open. In four patients absence of bone and enhancement of adjacent membranes simulated an aggressive process such as metastatic neuroblastoma. In four additional cases nodularity of the membranes and irregularity of the osseous margins also suggested an aggressive process. Clinical follow-up in these patients showed no evidence of a systemic illness. C o n c l u s i o n : The anterolateral and posterolateral fontanelles are patent at birth and usually close by six months. Marked enhancement and irregularity of the fontanelles may be seen in the absence of an aggressive process.

P-66

CHRONIC SUBDURAL FLUID COLLECTIONS IN INFANTS

Tkacova, J., Brozmanova, H., Vajda, P. : Neurologic Department Children's hospital Comenius , University in Brat&lava ,Slovakia The purpose was to give the indications for surgical treatment. The differential diagnostic problems in the group of 4 infants after cranial trauma compared to etiology of 14 patients with subdural effusions. A shaken infant may suffer only mild ocular or cerebral trauma. External pressure on the skull during delivery can further promote haemorrhage. Excessive moulding and sudden changes in pressure can result in intracranial damage. Subdural haemorrhage caused by shearing forces disrupting small bridging veins over the surface of the brain is a common result of shaking In the group of our infants such haemorrhage was most prominent in the interhemispheric fissure Cerebral oedema with or without subdural haemorrhage may be the only finding on USG, CT. CT is more sensitive than MRI in detecting acute subdural haemorrhage. Shaken baby syndrome is frequently overlooked in its most subtle form and underdiagnosed in its most serious expression The caretakers may misrepresent or have no knowledge of the cause of the brain injury There is often an absence of externally visible injury.We present the radiologic and clinical findings that support the chronic subdural effusions. The reports of benign subdural effusions remain unsubstantiated since multidisciplinary evaluations in the groups of our patients were lacking.When these severely injured

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children survive, they may have chronic subdural fluid collections, enlarging ventricles, cerebral atrophy. The surgery may also be indicated for removal some of subdural effusions.The consequence of shaking to infants who do not come to medical attention is presently unknown.

P-67 A N T E N A T A L D I A G N O S I S OF VEIN OF G A L E N A N E U R Y S M A L M A L F O R M A T I O N (VGAM): AN IN VIVO M R STUDY OF F E T A L BRAIN.

Campi A, *Filippi M, ~ F, Triulzi F, Pereira C,**Lasjaunias P.Neuroradiology and * Neurology Departments HS Raffaele, University of Milan. ~ Department, University of Pisa, Italy** Bicetre Interventional Neuroradiology Unit, University of Paris. A pregnant woman underwent standard pelvic sonography during the 32nd week. An echoic lesion of the midline brain structures was detected and the possible differential diagnoses were choroid plexus cyst, arachnoid cyst or abnormal dilatation of the third ventricle. However, Doppler sonography, revealed the presence of blood flow within the lesion and therefore a diagnosis of VGAM was proposed. At the 36th week of pregnancy MR was performed, utilizing 1.5 T magnet and the following spin-echo sequences: T1 W1 500/15, T2WI 2400/22/120. Axial , sagittal and coronal slices were obtained with different matrices, and different FOV of 350, 400 and 500 and thickness of 5 and 6 ram. A whole body coil was centred on pelvis between the umbilicus and the pubic symphysis of the woman. Pre-saturation slabs were necessary to m i n i m i z e the i n t e r f e r e n c e of the a b d o m i n a l movements, and diazepam per os (4rag) was given to reduce fetal movements. MR displayed dilatation of vein of Galen without thrombosis of the straight sinus or any other AV malformation and confirmed the suspected VGAM. Brain parenchyma was normal, only slight enlargement of the right lateral ventricle was detected without any other brain abnormalities. Also a mild dilatation of the heart was found. These latter findings, barely showed by sonography are essential to establish prognosis, indications to embolization and the planning of eventual early management of this disease.

S 115 POSTERS P-68 A N O M A L I E S OF N E U R O N A L M I G R A T I O N : APPLICATION OF M P R A G E , 3 D F T - T 1 - W GRADIENT ECHO SEQUENCE De Blasi R., Andreula C.F, Beltomo R*, Specchio L.M ~ and Carella A. Cattedra e Servizio di Neuroradiologia - Universitgt di Bari. *Divisione di Neurologia - Policlinico. Bari ~ Clinica Neurologica - Universitgz di Bari. Ospedale Policlinico, Piazza G. Cesare, l t.Bari. Italy. P u r p o s e : The authors propose the technique Tl-w MP RAGE for the detection of neuronal migration diseases (NMD), especially indicated for localised forms. The application of this technique derives from the possibility to obtain more details of the cortical profile and the interface between white and grey matter. Materials and Methods : 15 patients, all presenting neuronal migration disorders, and followed for epileptic syndromes were examined with a threedimensional, Tl-weighted Gradient-Echo sequence called MP RAGE (Magnetisation Prepared Rapid Gradient-Echo), obtained on a Siemens Impact 1.0 T. Results : MP RAGE images were considered superior to SE T1 and T2W sequences especially for the detection of small cortical dysplasias and the d i f f e r e n t i a t i o n b e t w e e n l o c a l i s e d areas of micropolygiria and pachygiria. C o n c l u s i o n : Our purpose of application of the MP RAGE sequences for the study of neuronal migration disturbances derives from the necessity to define accurately the nature of the lesion and its extension, even for the eventual surgical treatment in the most drug-resistant forms.The accurate differentiation between pachygiria and micropolygiria is necessary for their different etiopathogenesis, the first being more linked to genetic disorders, the last to acquired factors, above all ineffective, and expressed with vascular damage.The MP RAGE sequence represent an useful diagnostic tool for the advantages represented by three-dimensional technique: slice thickness of 1-2 ram, images heavily Tl-weighted, the possibility of multiplanar reconstruction along planes different from the acquisition one, with the MPR algorithm. With this technique, the thickness of cortical grey matter is easily calculate, and the presence of subtle interdigitations between cortex and sub-cortical white matter are better defined.The Authors propose the application of MP RAGE technique in the study protocol of the anomalies of neuronal migration.

P-01 - P-116 P-69 A CASE OF C O M P L E T E D O U B L E C E R E B R A L CORTEX Bastianello S, Paolillo A, Sideri G, de Lena C, Gennaio M, Bozzao A, Fantozzi L.M, Bozzao L.Dipartimento di scienze neurologiche- Universita "La Sapienza" Viale dell'Universitdt, Roma

Disorders of neuronal migration, when diffuse, produce large heterotopic neuronal masses, usually associated with severe intellectual deficit and epilepsy.We report a severe disorder of neuronal migration consisting of a complete double cortex, demonstrated by MRI in a 23 years old woman with mental retardation associated with intractable epilepsy. Neurologic examination showed a diffused hipotonicity concerning the neck and the head with stable attitude of head flexion, halfopen mouth of saliva.The electroencephalogram showed a paroxystic bursts of generalised slow spike and wave discharges and global slowing down of the background activity a typical patterns of LennoxGastaut syndrome. MRI scan showed a complete subcortical laminar heterotopia of grey matter, situated between the cortex and the ventricular wall and separated from both by well developed layers of white matter. The abnormal grey layer extended from the frontal to the parietal and temporal region. This layer was also clearly seen on T1 weighted sagittal images. The cortical gyri had a convolution pattern of lissencephaly.Two previous CT showed only a moderate dilatation of lateral ventricles compatible with a subcortical atrophy picture.This case emphasises the value of MR imaging in diagnosing disorders of neuronal migration in respect of previous imaging techniques.

P-70 C H A N G E S OF C E R E B R A L B L O O D F L O W MEASURED BY STABLE-XENON-CT IN PATIENTS WITH LONG-STANDING H Y D R O C E P H A L U S PRE- A N D P O S T S H U N T OPERATION Voges M,Kiefer M*, Neidl K,Hermes M, Piepgras U, Steudel WI* Institute of Neuroradiology and *Department of Neurosurgery, Saarland University, Homburg / Saar,Germany Purpose: Patients with hydrocephalus have inconstant symptoms leading to difficulties in the decision weather an operation is indicated or not. Experimentally hydrocephalus is known to induce a profound change in c e r e b r a l m i c r o - and macrovasculature. We investigated the correlation between pre- and postoperative cerebral blood flow (CBF) and pre- and postoperative hydrocephalus symptoms

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POSTERS Material and Methods: In 9 patients with different

causes of long-standing-hydrocephalus CBF was measured by st-Xe-CT pre- and post shunt-operation Also clinical symptoms of hydrocephalus and preoperative intracerebral pressure (ICP) were registered We used a GE CT 9800, a stable-XenonGas-Enhancer, a Spiegelberg-ICP-epidural- measuring unit and an especially developed hydrocephalussymptom-scale. Results: In all patients the preoperative CBF was subnormal and the postoperative examination showed a normalization in CBF Corresponding to the increase of CBF there was an amelioration in the patients clinical symptoms The average improvement of CBF and Hydrocephalus scaling was 45 percent after shuntoperation An increase in ICP was recorded during Xenon-Inhalation, in one case 50 percent from the baseline. Discussion: Obviously there is a correlation between the CBF and the clinical symptoms The changes in CBF induced by hydrocephalus seem to be reversible and that may be the reason for the clinical benefit after shunting. ICP monitoring during st-Xe-CT is indicated because of the potential risk of ICP increase

P-71 CT APPEARANCE OF ACTIVE HYDROCEPHALUS IN ADULTS-VERIFICATION BY ICP MEASUREMENTS.

Kordek P., Kotwica Z Department of Medical Imaging and Department of Neurosurgery, Medical University of Lodz, Poland Long-term intracranial pressure measurements were performed in patients with typical CT appearance of active hydrocephalus in order to verify if there are ICP signs of active hydrocephalus process. 49 patients were included into this study with clinical and CT symptoms of hydrocephalus. In all these patients 24-43 hours of ICP measurements were performed using Camino system. In 37 patients ICP measurements revealed significant rise in ICP, which appeared mainly during sleep, what proved that active hydrocephalus exists and shunt surgery is necessary. In 12 patients/25%/ICP measurements did not reveal any rise in ICP during 48 hours of ICP measurements and the patients were diagnosed as cerebral atrophy. Results of this study suggests that typical CT appearance of active hydrocephalus does not prove the real necessity for shunt surgery and ICP measurements should be performed before the surgical decision of shunting.

P-72

CYSTICERCOSIS : RADIOGRAPHIC AND RESONANCE IMAGING OF CENTRAL NERVOUS SYSTEM (C.N.S.) I N V O L V E M E N T IN DIAGNOSIS AND F O L L O W

MAGNETIC

UP OF T R E A T M E N T .

Dimitriadis A., Haritanti A, Kouskouras K, Prapavessis S, Paschalidou M. A.H.E.P.A University Hospital : Neuroradiology Department : Thessaloniki : Greece Infestation of the Central Nervous System with cystic larvae of Taenia Solium ( cysticerci ) is relatively rare in Greece. The characteristic radiographic ( plain radiography and Computed Tomography) and Magnetic Resonance Imaging (M.R.I.) findings in a series of 7 patients are reviewed: They included: 1. Multiple cystic parenchymal brain lesions. They exhibited asymmetric distribution, multiple punctuate calcifications and occasional ring enhancement on intravenous contrast administration, as well as slight perifocal oedema, depending on the cycle of the parasite. 2. Subependymal lesions. 3. Hydrocephalus associated with a chronic meningitis ( 1 case ) 4. Characteristic soft tissue lesions associated with C.N.S involvement. The diagnoses were confirmed by serologic tests, excision of subcutaneous lesions, biopsy at surgery and C.N.S. fluid examination (1 case). Five of the patients currently under treatment have been followed for a period of two years to two months and the findings of these consequent examinations are correlated with the original lesions.

P-73 I N F E S T A T I O N OF THE C E N T R A L N E R V O U S SYSTEM WITH HYDATID DISEASE

(ECHINOCOCCOSIS) Prapavessis S., Haritanti A, Kouskouras K, Dimitriadis A A.H.E.P.A University Hospital, Thessaloniki Greece (Neuroradiology Department) The parasitic infestation of the central nervous system ( C . N . S ) b y larvae of Echinococcus Granulosus is relatively common in Greece. Possible sites of involvement include :1. Parenchymal cystic lesions of the brain.2. Involvement of the spine at various levels.3. Intraorbital lesion.Our material consists of 6 patients examined between 1988 and 1994 and include 2 cystic lesions of the brain( 1 supratentorial 1 infratentorial ) 3 spinal lesions and 1 orbital lesion. Intracranial lesions presented with focal neuro- j logic Signs and raised intracranial pressure. Spinal lesions presented with paraplegia( 2 cases ) and Brown Sequard syndrome ( 1 case ).The orbital lesion caused unilateral exophthalmus. All lesions were confirmed at surgery. The radiographic (plain radiography, Computed Tomography ) and Magnetic Resonance

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Imaging findings are presented with special emphasis on Magnetic Resonance Imaging of the spinal lesions.

P-74 CEREBRAL BLOOD FLOW IN V I R A L MENINGOENCEPHALITIS ASSESSED BY 99MTC-HMPAO-SPECT

Muller M 1, Neid K.F.W1, Hasert K 1, Schimrigk K 1, Piepgras U, Institute of Neuroradiology and Department of Neurology, Saarland University Hospital, Oscar-Orth-str. 1,Homburg/Saar In 15 patients (9 female, 6 male, age range 23-75 years) with viral meningoencephalitis 99mTC SPECT investigations (ca. 370 MBq for each study) were performed 2-27 days (mean 11 days) after onset of symptoms. Viral meningoencephalitis was diagnosed by at least headache, meningism and fever with or without accompanying symptoms in association with a lymphocytic (>90%) pleocytosis (> 13/3 cells). The 15 patients does not include patients with characteristic Herpes Simplex encephalitis or multiple sclerosis. In 5 of the 15 patients an additional HMPAO-SPECT was performed after application of 1 gr acetazotamide i.v using the substraction technique for evaluating the cerebral perfusion reserve capacity. Using the cerebellar regions as reference area the SPECTs were analysed visually according to: a) global tracer uptake, and b) focal abnormalities (increased/reduced tracer uptake) comparing the regional uptake within one hemisphere and with respect to any side-to-side difference. As a result, in all except two patients global tracer uptake was marked in homogeneously. Regional abnormalities were present in all but two SPECT examinations with a predominance of the frontal and parietal regions. In 4 of the 5 acetazolamide studies perfusion reserve was disturbed diffusely (2) or focal (2). Focal SPECT findings correlated in 2 patients with corresponding focal clinical symptoms. We conclude that cerebral blood flow is frequently disturbed in viral meningoencephalitis but without a striking correlation to the clinical signs

P-75 B R A I N M R I C O R R E L A T E S OF C O G N I T I V E I M P A I R M E N T IN P R I M A R Y A N D S E C O N D A R Y P R O G R E S S I V E M U L T I P L E SCLEROSIS.

Comi G, Filippi M, Martinelli V, Rodegher M, Campi A*, Rovaris M, Reganati P*, Scotti G*.Departments of

Neurology and *Neuroradiology - IRCCS H.S.Raffaele, Milan (Italy). Purpose: The aim of this study was to evaluate brain magnetic resonance imaging (MRI) correlates of cognitive impairment in Primary Progressive Multiple

P-O1 - P-116 Sclerosis (PPMS) and in Secondary Progressive MS (SPMS). Material and Methods : Brain MRI and an extensive battery of neuropsychological tests, exploring frontal functions, short and long-term memory, visuo-spatial skills, attention and language, were obtained in 14 patients with PPMS and 17 patients with SPMS. Patients were considered to be cognitively impaired when at least 3 neuropsychological tests were abnormal. MRI was performed with a 1.5 T machine and the lesions were counted and sized for 16 anatomical regions. Results: The clinical parameters were similar for the two groups. Cognitive deficits were found in 9/17 SPMS patients and in 1/14 PPMS patients (p--0.01). Patients with SPMS had higher MRI total (p=0.004), periventricular (p=0.008) and nonperiventricular (p=0.004) lesion loads than patients with PPMS. Nonperiventricular lesion load was greater for SPMS patients with cognitive impairment than for those without such deficits (p=0.005). Conclusion : Our results indicate that both neuropsychological and brain MRI abnormalities are more important in patients with SPMS. Since physical disability was similar for the two groups, this suggests that disability in PPMS is predominantly due to spinal cord involvement.

P-76 I N T E R - O B S E R V E R C O N C O R D A N C E OF B R A I N M R I L E S I O N V O L U M E M E A S U R E M E N T S IN M U L T I P L E SCLEROSIS.

Filippi M, Campi A*, Baratti C*, Reganati P*, Horsfield M.A **, Mammi S, Comi G.Department of Neurology and *Neuroradiology - IRCCS H.S.Raffaele, University of Milan, Milan (Italy). **Department of Medical Physics, Royal Leicester Infirmary, Leicester (UK). Purpose : Quantitative assessment of magnetic resonance imaging (MRI) lesion loads in multiple sclerosis (MS) is the best way to evaluate the natural history of the disease and the efficacy of treatments. Since such studies usually need multicenter cooperation in which many observers might be involved, this study was planned to evaluate the interobserver concordance of lesion volume measurements. M a t e r i a l and M e t h o d s : Brain MRI scans (1.5 T machine, SE 2000/50, 5 mm contiguous axial slices) were obtained for 8 clinically definite MS patients and were evaluated independently by 3 observers. The abnormalities were measured both by a quantitative semi-automated technique and by an arbitrary scoring system. R e s u l t s : The Kendall's coefficient of concordance was high for both the assessments of brain MRI abnormalities perhaps because the long time the observers have been working together, but was higher

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for the quantitative assessment (arbitrary scoring system: W=0.92, chi2=19.44, p<0.006; semiautomated method: W=0.98, chi2=20, p<0.003). C o n c l u s i o n : These data indicate that quantitative assessment of lesion volumes in MS not only allows more objective results to be obtained, but also gives a high inter observer concordance.

P-78 TOWARDS GEOMETRIC C H A R A C T E R I Z A T I O N OF THE N O R M A L CORPUS C A L L O S U M

P-77 M A G N E T I Z A T I O N T R A N S F E R OF E N H A N C I N G AND NON-ENHANCING LESIONS IN M U L T I P L E SCLEROSIS.

P u r p o s e : Find geometry characters of the corpus callosum which are invariant in normal brains. Examine if, according to these criteria, the brains with multiple sclerosis are different 'from the normal ones. Material and Methods: 40 3DFT MRI acquisitions (G.E.M.S. Signa 1,5 T) - 20 normal young adults, 20 a g e - m a t c h e d patients with multiple sclerosis. Measurements are done on films and with a workstation (GE-SDC).The measured items are surfaces curvatures, curvilinear lengths and planar areas. Their mutual relations are compared with those of characteristic g e o m e t r i c objects (extremal surfaces). They are thus automatically normalised. Results:They are expressed as permissible deviations from these characteristic objects, they are not totally available yet. But it is clear, for example that the deep surface of the middle part of the corpus callosum is close to a minimal surface. Conclusion: To find r e l e v a n t g e o m e t r i c characteristics, the corpus callosum has to be studied as a 3-dimensional structure and not only in the median sagittal plan. Its shape is partly dependant upon the growth and the development of the brain.The ultimate goal of this work is to unveil minor developmental abnormalities which result in unusual stress on some on some components of the white matter bundles.

Carnpi A, *FiIippi M, *Corni G, Baratti C Gerevini S, Scotti G.Departrnents of Neuroradiology and *Neurology, IRCCS S. Raffaele, University of Milan, Italy. P u r p o s e : The aim of this study is the evaluation of the m a g n e t i z a t i o n transfer (MT) effects on gadolinium-enhancing and non-enhancing lesions in multiple sclerosis. Materials and Methods: MT studies were performed on a 1.5 T MR unit with TR=600ms, TE=12ms, flip angle=20 ~ matrix size=192X256, section t h i c k n e s s = 5 m m and interslice gap=0.4 mm. A saturation 1.5 kHz off resonance pulse was applied. The bandwidth of the pulse was 250 Hz. The MT ratio was calculated according to the formula published by Dousset et al. (Radiology 182: 483-491,1992). 21 clinically definite MS patients(18 R e l a p s i n g Remitting and 3 Secondary Progressive) and 9 healthy controls were studied. R e s u l t s : We evaluated 26 gadolinium-enhancing lesions, 219 non enhancing lesions, and 46 areas in the centra semiovalia of the normal appearing white matter (NAWM). Lesions had significantly lower MT ratio compared to the N A W M of the patients (p<0.0001) and the normal white matter of the healthy controls (p<0.000t). However no difference was found between MT ratio in enhancing and non enhancing lesions (39.9% vs 40.9%). The 26 enhancing lesions were divided in two subgroups: A)with homogeneous enhancement (18 lesions), B) with ring enhancement (8 lesions). MT ratio were lower in subgroup B (average value:33,4%+ 8,8) in comparison with subgroup A (average value: 37,4% +5,1) C Conclusion: Our results may be due to the variability of pathological pattern in both enhancing and nonenhancing lesions. The difference of MT ratio values between different pattern of enhancing lesions seem to indicate that in chronic reactivated plaques there is more relevant expansion of the extra cellular spaces.

Stievenart J.L, Iba-Zizen M.T, Cabanis E.A, Wu B.S, Tourbah A, Abanou A, Trad M, Thibierge M, Lopez A, Bodiguel E. A.R.S.E.P. Neuroradiology Dept, Ctre Hosp. Nat. Opht. XV/XX, Paris, France

P-79 CT ANALYSIS OF P O S T O P E R A T I V E C H A N G E S IN THE T H A L A M U S OF P A R K I N S O N DISEASE

Zhang G.G. Q. Department of Radiology, Xijing Hospital of Fourth Military Medical University, Xi'an China Stereotactic operation has long been used to relieve the agitation and muscle rigidity in Parkinson disease. On account of its high density resolution CT is quite effective to portray the location, size, shape and density of the thermocoagulative focus. The foci were classified into different types according to their changes in different periods. Correlation with pathological changes was discussed.

S 119 POSTERS P-80 M R A N D CT F I N D I N G S IN F I V E CASES OF C E N T R A L P O N T I N E M Y E L I N O L Y S I S (CPM) . C L I N I C A L P R E S E N T A T I O N AND O U T C O M E .

Coskun O.,Huet H.,Toulas P., Courtheoux P. Department of Neuroradiology and Interventional Radiology. Magnetic Resonance Unit. Caen C.H.U., Avenue de la C6te de Nacre Caen cedex, France Purpose : The authors report five cases of CPM. Clinical and biological circumstances as well as MR appearances are detailed. M a t e r i a l a n d M e t h o d s : 5 patients with acute brainstem dysfunction (4 men and 1 woman, aged between 38 and 67), were examined on MR 1.5 T . All had had a CT scan performed previously. The pontine lesions were characterised according to location, shape and T1 and T2 signals. Any electrolytic abnormality was noted. Mean follow-up was 6 months. Results : No relationship was found between MR appearance and patient outcome No gadolinium e n h a n c e m e n t was observed. Central Pontine Myelinosis may occur in the absence of hyponatremia (3/5). A fatal outcome is unusual (1/5) in the absence of a preexisting debilitating condition. Conclusion : CPM remains incompletely understood as far as clinical course and outcome are concerned. Radiological features have been well characterised since the advent of MR.

P-81 M A R C H I A F A V A - - B I G N A M I DISEASE (M.B.D.). CT AND MRI F E A T U R E S AND D I F F E R E N T I A L DIAGNOSIS.

Pujol, T .; Berenguer J," Del Amo, M.; Careddu, A .; Vazquez, F .; Salvado, E .; Cardenal, C.; Tomas, X.; Anguera, A.; y Mercader, J. M.Hospital Clinico y Provincial de Barcelona. Univercidad de Barcelona. To present the CT and MRI features and the differential diagnosis of Marchiafava-Bignami disease We present two cases of M.B.D., diagnosed clinically and by imaging, and various pathologic conditions, involving the corpus callosum. In both patients, CT scans revealed hypo density in the corpus callosum. In one of these patients MRI showed a low-signal intensity area in Tl-weighted images, and a high-signal intensity area in T2 -weighted images in the same location Other diseases may show similar findings. The primary demyelination of the corpus callosum (M.B.D. ) is a rare c o m p l i c a t i o n of chronic alcoholism, presumably of nutritional or metabolic origin. Neuroimaging with CT scans demonstrate hypo density in the corpus callosum without contrast enhancement., and in MR imaging, hypo intensity in Tl-weighted images and hyperintensity in T2-weighted

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images in t he same abnormal area.Similar findings in CT and MRI may be observed in other conditions, such as ischemic, neoplastic, traumatic, infectious and toxic disorders, and in other demyelination diseases.

P-82 FUNCTIONAL BIOIMPEDANCE IMAGING. COMPLEMENTARY COMMUNICATION N E T W O R K OF THE SKIN.

Babich YF, Potashko AS, Fomenko IS. Ukraine Academy of Science. Rea. Ctra. Dipri and Sonar. Kiev. Ukraine. The aim of this work was to investigate some dynamic features of electrical bioimpedance relief of the skin (EBRS) and thus to find out : (i) in vivo some possible manifestations of intercellular communication system at the skin; and (ii) some E B R S ' d i s t i n c t i v e f e a t u r e s of n o r m a l and morphologically changed biotissue. We used specially developed experimental technique for non invasive visualizing the EBRS of 20x40mm resolution. The zones under observation included a nerve-trunk and some local electroabnormality, i.e : a neoplasm, an acupuncture point (AP), a scar, etc. As test influences we used distant high-frequency EMF of extremely low intensivity (rose noise 0.01mW/sg.cm), distant and local mechanical irritation, and distant painful electrostimulation. 30 ill and healthy subjects (360 frames) have been investigated.

P-83 C O M P U T E D T O M O G R A P H Y AND M A G N E T I C R E S O N A N C E I M A G I N G IN C O A T ' S DISEASE

Mercader JM, Montull C, Peri J, Perich X, Pujol T, Rovira M, Bertomeu M, Garcia G. Centro Radiologico Computarizado. Barcelona. Spain. P u r p o s e : To show CT and MRI findings in Coat's disease which is a primary vascular anomaly of the retina characterised by t e l a n g i e c t a s i s and accumulation of l i p o p r o t e i n a c e o u s exudates (cholesterol and macrophages) that can also be found in the subretinal space. Material and Methods: A 3-year-old boy was tended at the Ophthalmology Department suspecting him to have a right ocular tumour. CT revealed a slight reduction of the right globe, an increase of its density in the posterior pole and a small calcification, too. MRI depicted an intraocular polylobulated image in the right eye -of high-signal intensity in Spin-echo sequences and showing a small Ievel in its middle part con'esponding to methemoglobin. The differential diagnosis was established between retinoblastoma and Coat's disease. The final histologic diagnosis was Coat's disease.

S 120 POSTERS Results: The differential diagnosis between retinoblastoma and Coat's disease is established in its infantile expression which is considered to be the earliest and most severe of all. Usually, Coat's disease is asymptomatic until exudates affect the macula, causing either strabismus or loss of visual acuity. C o n c l u s i o n : The key diagnostic findings are the presence of cholesterol crystals, pigment-laden macrophages and the absence of tumour cells in fresh preparations. CT is a valuable test because of its ability to delineate intraocular morphology, identify subretinal space abnormalities and detect calcium. MRI is valuable for its multiplanar imaging capabilities, its superior contrast resolution and its ability to provide insights into the biochemical structure and composition of tissues.

P-84 COCHLEAR OTOSCLEROSIS: COMPARISON BETWEEN VISUAL EVALUATION A N D D E N S I T O M E T R I C CT A N A L Y S I S W I T H AUDIOMETRIC CORRELATION.

Ada E, Giineri A, Tutpinar Y, GiSktay Y ,Kovanlikaya I, Pirnar T Dokuz Eyliil University Medical Faculty Izmir Turkey Cochlear otosklerosis is a progressive disorder of the otic capsule characterized by sensorineural hearing loss and bone structure modifications. Audiometric evaluation of these patients can determine the degree of sensorineural hearing loss and the specific frequency levels involved. CT is the best imaging method to detect the affected cochlear capsul. CT densitometry constitutes an objective approach to establish the evaluation of the disease after medical or surgical treatment. Twenty patients who had surgically confitmed fenestral otosclerosis and nine patients who had audiometrically suspected cochlear otosclerosis underwent CT examination. Demineralized foci of otic capsule weree investigated visually and by densitometric analysis (histogram, densitometric profile of Valvassori and method of Huizing and De Groot). The findings were correlated with audiometric results and compared with the control group. Densitometric studies were found to be useful for the cases which cannot be.diagnosed visually before significant demineralization occured and after medical treatment. Bone density loss was primarly and frequently seen in the basal turn of cochlea and a good correlation was found with audiometric results.

P-01 - P-I16 P-85 D I A G N O S I S BY CT A N D M R OF P A T I E N T S W I T H N E U R O S E N S O R I A L H E A R I N G LOSS OF C O C H L E A R ORIGIN

de Juan-Delago M, Ruscalleda J, Guardia E, Feliciani M, Coll S, Simo N and Ruza M S. de Neurorradiologia. Hospital de la Sta. Creu i S. Pau. Universitat Autonoma. Barcelona. Spain. P u r p o s e : CT study is able to demonstrate cochlear lesions and at the same time to provide criteria for the solution of differential diagnosis. MR imaging is useful in cochlear lesions without bone involvement. Material and Methods: We revised 308 CT studies performed in patient affected by neurosensorial hearing loss (NSHL) or mixed hearing loss in which a cochlear lesion was suspected.CT study protocol included axial scanning with 1 to 2 mm thick slices, and coronal scanning and multiplanar reformatting when pathological changes were found. MR study with axial T1 and T2-weighted pulse-sequences and axial Gadolinium-enhanced T l - w e i g h t e d pulse sequences was performed in 16 of these patients R e s u l t s : In 73 out of 308 patients internal ear pathological changes were found by CT, which correlated with the clinical alterations: 14 internal ear malformations, 11 labyrinthine fractures, 20 cochlear otospongiosis, 4 Paget's disease with cochlear involvement, 17 labyrinthitis ossificans, 4 congenital cholesteatomas of the petrous bone with labyrinthine extension; and 1 case each of recurrent cholesteatoma of middle ear with internal ear invasion, acute bacterial labyrinthitis and osteogenesis imperfecta tarda.A case of acute viral labyrinthitis was diagnosed by MR, without pathological CT changes. C o n c l u s i o n : NSHL can be due either to a cochlear lesion or to a retrocochlear pathology. Clinical evaluation, audiometric testing and brainstem evoked potentials permit to reach a rather precise location of the lesion. CT study depicts the involvement of the bony labyrinth in all cases in which it occurs. CT permits to reach an etiologic diagnosis in the case of congenital malformation, internal ear fracture and dysplasia (otospongiosis, Paget's disease, osteogenesis imperfecta), and the extension to the internal ear of infectious processes originating at level of the middle ear or intracranially. MR is superior to CT in the depiction of labyrinthine lesions which are not associated to bony changes.

S 121 POSTERS P-86 NEURORADIOLOGICAL EVALUATION BEFORE COCHLEAR IMPLANTATION 1N CHILDREN.

Soulie N, Bonafe A, Cha FI, Fraysse B, Deguine O, Corrnay X, Mondain M, Uziel A.Departments Neuroradiology, ORL, CHU Purpan Toulouse ORL Montpellier. 56 children who were implanted with multichannel nucleus system were evaluated for labyrinthitis ossificans and possible cerebral abnormalities with CT. Round window (RD) (12 cases), basal turn (8 cases) and complete cochlear ossifications (4 cases) depicted at surgery were only correlated with positive CT findings in 2 cases (basal turn ossification).One case of CMV infection, plain brain CT disclosed parenchymal calcifications.Poor resolution CT failed to demonstrate RW membrane and limited scala tympani ossifications. Technical requirements to achieve a complete evaluation of cochlear patency are mandatory. Labyrinthitis, inner ear deformities, osteogenesis imperfecta should be depicted.MR evaluation has not been carried out in this population but may offer the opportunity of a direct assessment of cochlear liquids.

P-87 CT D E T E R M I N A T I O N OF T R A U M A T I C F O R C E D I R E C T I O N IN CLOSED HEAD INJURY

Besenski N, Broz R University Hospital Rebro, Zagreb, Croatia The aim of our study was to determine the traumatic force direction using CT in patients who suffered closed head injury. We analyzed CT scans of 45 patients performed within 1 - 24 hours after the injury. On CT scans each patient's transversal cut of the skull was divided into 12 sections, imitating the clock-face. Such a procedure was carried out to make possible for the computer to graphically present the direction of the traumatic force. In most of the cases determination of traumatic force direction was based exclusively on CT findings of skull fractures and/or soft tissue swelling as well as coup and contre-coup lesions. In the remaining cases the traumatic force direction was determined both on the clinical findings and on the CT scans visible contusions ipsolaterally or bilaterally. Skull fractures were found in 36% and soft tissue swelling in 71% of the cases. Coup, contre-coup lesions and coup + contre-coup lesions were found in 20%- 13% and 67% of the cases respectively. In 80% of the cases the traumatic force-direction was determined e x c l u s i v e l y by CT and presented graphically. Traumatic force acted along the longest axis of the skull, fronto-occipital in one and occipito-

P-01 - P-116 frontal direction in 3 patients. In 21 patients the left side of the skull was hit and in 20 patients the right side of the skull was affected. The most frequent traumatic force direction was from parietal region on the right to the frontal region on the left. CT has been shown to be a very useful and reliable tool in assessing the traumatic force direction. The data obtained by such procedure can have far-reaching prognostic and forensic implications.

P-88 S U P E R F I C I A L S I D E R O S I S OF R A R E C A U S E OF E M P O T A N C E BY MRI

THE CNS:A DIAGNOSED

Ada E, Kovanlikaya I, G6ktay l, Genc K, Fadiloglu S, Pirnar. T Dokuz EyliiI University Medical Faculty, Izmir, Turkey. Superficial siderosis (SS) of the CNS is a rare disorder characterized by deposition of the ironcontaining pigment hemosiderin in the leptomeninges and subpial tissue. Today MRI is the first noninvasive diagnostic tool in detecting hemosiderin deposits in these tissues. Two patients with SS diagnosed by MRI who suffered from mild cerebellar symptoms, monoparesis and autonomic nervous system s y m p t o m s such as ejaculation and erection disturbances are presented. The first case had an intradiploic leptomeningeal cyst in the occipital bone and there was no hearing loss, while the second case had a history of an injury of colurmna vertebralis with a pin at the level of the 7th dorsal vertebrae and bilaterally asymetrical hearing loss. Both of them had been scanned by MRI for investigation of clinically suspected multiple sclerosis. T2 weighted MR images showed typical hernosiderin deposition infra and supratentorial subpial and leptomeningeal tissues in both cases. Brainstem and spinal cord were normal in the first case, but were affected in the other; and in this second patient, hemosiderin deposits were also seen on the surface ot the paravertebral muscles of the cervical and dorsal vertebral column. Today, detection of the SS ot the CNS is easier and noninvasive with MRI. Therefore, the reports about this subject continue to increase in the current literature but clinical signs and etiologic events are still variable and non specific.

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POSTERS P-89 A P H A S I A IN A C O N G E N I T A L L Y D E A F A D U L T .

Barroche G, Lacour JC, Braun M, Lonchamp P.Department of Neurology (Pr Weber) Hospital St Julien Nancy FranceDepartement of Neuroradiology (Pr Picard), Hospital St Julien Nancy France. The aim of this paper is to describe an aphasia in a right-handed congenitally deaf man and to specify the location of the injury. Mr Michel M. was a 56 year-old, right-handed, washer-up in a restaurant, congenitally deaf man. With his family he conversed by sign language and lip-reading. Every day he read newspaper, he wrote and calculated poorly. He was an hypertensive treated by Captropril 100mg and Diltiazem 300mg p.d.On 5th august 1991 he had a cerebral vascular accident. His blood pressure was 200-110mmHg. He was stuporous during 24 hours and had a massive right motor and sensitive hemiplegia. The first CT examination (5th august) showed a large hematoma located in the left external capsule extending toward the insular cortex laterally, the putamen medially, the white matter of the pars triangularis of the inferior frontal gyrus anteriorly, the lower portion of the internal capsule posteriorly.On 1 ltb august, he has recovered standing position but the right arm remained helpless. At a second CT examination (28th august) the hematoma's evolution was uneventful becoming hypodense and showing an hypodense extension to the posterior limb of the internal capsule.The first days after CVA he was inhibited to communicate. Then he exhibited defective expression and understanding in sign language and lip-reading. He was unable to understand very simple written orders as "Shut your eyes" or "Give me your hand" ; on 6 pictures representing unique simple things, he could match correctly 4 words. He could write by left hand but very poorly, he wrote wrongly his proper name. He had no apraxis.Four months later he walked, he had paresis of right arm, no hemianopsia. Now he could write by right hand c o r r e c t l y his name, the words corresponding to simple things showed to him. He could execute correctly written orders as "Shut your eyes", "Rise your right hand" or "Show your knee". He could add 257 to ll2.Eight months later his family considered his neuropsychological abilities were returned to the level before the CVA.The MR examination performed on 20th July 1992 showed on the T2 weighted sequence the remnants of the external capsule haematoma as a central hyperintense area surrounded by an hypointense rim of hemosiderin and ferritine. Moreover, destructive lesions of the left cortico-spinal tract were noted as hypersignal areas within the internal capsule, the left cerebral peduncle, the left pons and the medulla oblongata. C o n c l u s i o n : In this right-handed congenitally deaf man, an haematoma of left external capsule disorganised temporarily abilities.

P-90 CEREBRAL THROMBOSIS REAPPRAISAL

SINUS : THE

AND VENOUS ROLE OF CT A

Mull M., Utz N; Isensee C, *; Paselk C, **; Aulich A, **; Thron A, Neuroradiology/ * Neurology, RWTH Aachen;** Neuroradiology, University Di~sseldorf," Germany It has been suggested that CT examination is inconclusive in cerebral sinus and venous thrombosis (CSVT) due to a low rate of direct(21%) and indirect (52%) signs of CSVT (Bousser 1992).We report a retrospective study of 51 patients (34 females, 17 males) with angiographically and/or MRI-proven CSVT in order to evaluate the rate of specific direct (empty triangle sign, dense triangle sign) and unspecific indirect (oedema, hypodense lesion, haemorrhage) signs of CSVT in CT. 16 patients (31%) presented with acute clinical symptoms (alteration of consciousness, focal neurological signs, seizures) and entered hospital within 48 hours after onset of symptoms (group 1). In this group direct signs were seen as well as indirect signs in 12 of 16 patients (75%).35 patients (69%) had a subacute/chronic course (group 2). In this group direct signs of CSVT could be detected in 20 of 35 patients (57%), indirect signs in 25 of 35 patients (71%). 5 patients of group 2 had an initially normal CT.The analysis of the density pattern of the thrombus showed that the dense triangle sign appeared earlier and more frequent compared with the empty delta sign. In conclusion the rate of positive CT findings in CSVT increases distinctly if (1) t r a n s v e r s e and sigmoid sinuses are reviewed with different window settings and thin slices and (2) the dense triangle sign is taken into account.

P-91 CEREBELLAR HEMORRHAGIC

INFARCTION

Gouliamos A, Vemmos K.N., Kontogiannis M., Vlachos L., MouIopoulosS. University of Athens, Athens, Greece P u r p o s e : To describe incidence, CT/MRI findings, clinical features and outcome of cerebellar hemorrhagic infarcts (CBLHI). M a t e r i a l and M e t h o d s : We studied prospectively 350 consecutive patients with acute first stroke were admitted to University Hospital over one year period. R e s u l t s : We identified 130 patients with embolic stroke, who had one at least CT/MRI performed 3-15 days. 6 of 27 (22%) patients with cerebellar infarction (CBLI) had hemorrhagic transformation versus 25 of 103 (24%) without CBLI (NS) Stroke mechanism was cardiac embolism in 5 and intra-arterial embolism in 1. CBLHI involved 9 territories, full SCA territory in 4, lateral-SCA in 3 and full-PICA in 2 None of the

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patients was anticoagulated. During one year period follow-up, 4 patients were able to perform activities of daily living independently whereas 2 needed assistance. C o n c l u s i o n : CBLHI is not infrequent, has similar incidence and etiology to anterior circulation and did not influence outcome.

P-92 THE C O M P L I C A T I O N S OF THE C E R E B R A L A N G I O G R A P H Y IN O U R P A T I E N T S W I T H SUBARACHNOIDAL HEMORRHAGE

Mihale J., Porubec V., Bartko D., Traubner P., Vestenicka V. 1st Neurological Clinic, Comenius University, Bratislava, Slovakia The complications during and after cerebral angiography in a group of patients with subarachnoidal haemorrhage have been noted and analysed to discover the reasons and to avoid the disadvantages of this method. We had 210 patients during the period 1987-1993 years were we estimated intracranial aneurysms or the any vascular malformations as the reason of subarachnoidal haemorrhage (group 1). In the other group of 126 patients with subarachnoidal haemorrhage we did not prove the etiology of haemorrhage after the repeat angiography either (2 group). The control group of 220 patients with the different neurological disorders whom we had made cerebral angiography (3 group). The complications we divide in to 3 categories: local, total and neurological complications. The vasospasms of the cerebral arteries we measured on angiograms and compared with transcranial Doppler evaluations. We saw more complications of statistic significance in subarachnoidal haemorrhage group where the etiology was known (lst group) as in control trial. P is less than 0.001. Warning signs of cerebral angiography complications in the 1st group than 2nd group of patients. Delayed cerebral arteries spasms is better to follow with transcranial Doppler examination after cerebral angiography than measurement with neuroradiological index. C o n c l u s i o n : 1. First of all we refer the most neurological complications of statistic significance after the cerebral angiography in patients the 1st group of patients with subarachnoidal haemorrhage. 2. Spasms of the cerebral arteries are the reasons of neurological complications after carotid angiography in most of our patients. 3. We recommend transcranial Doppler evaluations as a sensitive method to detect arteriospasms. We prefer this method to measure the spasms with neuroradiological index.

P-01 - P-116 P-93

CLINICAL UTILITY OF INTRA-OPERATIVE ANGIOGRAPHY IN PATIENTS WITH A N E U R Y S M S AND SKULL BASE TUMORS

Bank W.O, Riedel C.J, Van Wadlington R, Sekhar L.N, Olan WJ. Neuroradiology and Neurological Surgery, The George Washington University Medical Center, Washington, D.C., U.S.A. P u r p o s e : To evaluate the clinical impact of modem techniques of intra-operativeangiography in patients undergoing surgery for aneurysms and skull base neoplasms. Materials and Methods: Portable C-arm fluoroscopy units with digital subtraction angiographic capability, and neurosurgical tables with radio lucent tops and head-holders are readily available. 64 patients with aneurysms or skull base neoplasms have undergone intra-operative angiography at GWUMC in the past year. Their clinical records have been reviewed from an outcome perspective. Results: Aneurysms: Even excellent surgical exposure is limited. Intra-operative angiograms can demonstrate clips that appear to be satisfactorily positioned but incompletely obliterate aneurysms, kink or compress normal arteries adjacent to the aneurysm or occlude normal arteries deep to the aneurysm neck. Immediate repositioning of these clips decreases the likelihood of neurological deficit from the sub optimal clip position. For cases in which midline aneurysms may require bilateral control of the carotid arteries but surgical exposure limits accessibility to one cervical carotid artery, a balloon catheter can be positioned angiographically for contralateral carotid control if necessary. Similar technique can be used for control in the vertebro-basilar system. Skull Base Neoplasms: Large skull base neoplasms that encase or invade the petrosal or cavernous internal carotid artery are now removed by techniques that bypass the arterial segment involved by tumor. A p p a r e n t l y adequate bypass grafts can be compromised by external compression, positional kinks, sub optimal anastomosis, or distal thromboembolus. Intra-operative angiography can identify these problems and lead to their immediate correction. No graft has failed after intra-operative angiography has shown it to be functioning well. Conclusion:Intra-operative angiography is a valuable adjunct to neurosurgery for aneurysms and skull base neoplasms. Correctable problems can be identified and addressed immediately without requiring the neurosurgeon to "go back in".

S 124 POSTERS P-94 COMBINED TREATMENT OF C O M P L E X C A V E R N O U S SINUS D U R A L A R T E R I O V E N O U S FISTULAS.

Beaujeux R., Brun F, Al-Fakir A, Sellal F, Oswald P, Zollner G, Casasco A, Bourjat P. Department of Radiology A, H6pital Central, H6pitaux Universitaires de Strasbourg, France P u r p o s e : Describe the different possibilities of medical and endovascular treatment of compIex cavernous sinus dural arteriovenous fistulas. Material and Methods: We retrospectively reviewed three charts of patients with right cavernous sinus dural arteriovenous fistulas fed by both external and internal carotid arteries. They were 1 male and 2 female. The average age was 71.3 years (range, 66-78 years). Patients presented with chemosis, conjunctival oedema, impairment of visual acuity (moderate in 2 cases and severely diminished in 1 case), headaches, diplopia (involving the third nerve in 2 cases and the sixth nerve in one case). All of them were first treated with manual compression and reduction of high blood pressure. We performed 10 procedures (1 to 5 per patient) to obtain a satisfactory clinical result; 2 through venous access (inferior petrosal sinus in one and facial vein in the other) and 8 through arterial access. We used variable stiffness catheters in 9 cases and classical angiographic catheter in 1 case. We used polyvinyl alcohol (8 cases) and platinum micro coils (1 case). Results: Total occlusion of the fistula was achieved in 2 patients. In the remaining case, the occlusion was partial with a dramatic reduction of the venous drainage. In all 3 patients, the objective findings disappeared after therapy. Complications encountered were: an ocular hematoma spontaneously regressive and a cerebral thromboembolic stroke (right middle cerebral artery occlusion) rapidly recanalised with local intra-arterial fibrinolysis and only with sensory deficit of the left hand. Conclusion: C o m p l e x cavernous sinus dural a r t e r i o v e n o u s fistulas often required several embolization procedures associated with appropriate medical treatment. Endovascular treatment allowed us to reach the vascular malformation either with arterial or venous catheterism. Complex cavernous sinus dural arteriovenous fistula is a rare vascular malformation for which embolization is an effective treatment.

P-01 - P-116 P-95 C A U T I O N S IN T R E A T M E N T OF P A R T I C U L A R ANATOMIC F O R M S OF I N T R A - C R A N I A L ANEURYSMS WITH TECHNICAL IMPLICATIONS.

Houdard E, Casasco A, Slaba S, Atymard A, Herbreteau D, Merland JJ.H@ital Lariboisi@re, Ddpartement de Neurosciences. Paris France. We encountered three specific situations in treating a total of 159 intracranial aneurysms by GDC coils. 1. Incomplete treatment : This corresponds to two anatomic situations : - Most frequently, spherical saccularform with a wide neck aneurysm cannot be embolized if large size GDC coil is not used first to form a squeletton followed by small size coils. In this situation, part of the large coil may protrude in the parent vessel.- The "en montgolfibre" form is that of a large spherical sac with cylindrical neck. The spherical compartment can be occluded easily while the cylindrical one remains patent. 2. Technical failures : This might happen also in large neck aneurysms. In this form, we recommend after advancing the coil and before detaching it, to perform two angiograms at an interval of 15 minutes. The second angiogram can show slowing of flow in the parent artery which must lead to withdraw the coil. 3. Thrombosis extension to the parent vessel : In our cases, the diameter ratio of the aneurysm to the parent vessel exceeded 3. In such anatomical situation we now recommend to inject preventively 100 000 units of Urokinase in the parent vessel at the end of the procedure.

P-96 E A R L Y M O R P H O L O G I C A L D E G R A D A T I O N IN CERVICAL ARTERY DISSECTION: 4 CASES REPORTS

Chavot D, Moulin T, Cattin F, Chopard J.L, Piotin M, Crepin-Leblond T, Bonneville J.F.Departments of Neurology, Neuroradiology. University-Hospital Besanfon France. Improvement of arterial lesions in cervical artery dissection (CAD) is the rule, except in case of aneurysm or thrombosis. Obversely early deterioration of CAD on angiography is not well-known. M a t e r i a l and Methods: Among 12 patients (pts) admitted consecutively for CAD, we found 4 pts with angiographic deterioration of CAD. Dissection diagnosis was made on clinical presentation (stroke) and n e u r o - i m a g i n g o v e r the first 24 hours (angiography in 3 cases, MRAngiography in 1), showing stenosis in all cases. Two pts had multiple CAD (4 arteries) and 2 a single dissection (internal carotid artery). All pts r e c e i v e d an urgent anticoagulation (heparin full-dose started within 12 hours after stroke onset). Aetiologies were traumatic

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causes in 2 pts (cervical manipulation in one) or undetermined in 2. None had a fibrodysplasia aspect. Vascular-imaging was controlled in 3 pts whereas they clinically improved and because of stroke recurrence in one. R e s u l t s : Deterioration of CAD were seen as new patterns (thrombosis or stenosis) on previously nonmodified arteries (1 case) or accentuation of CAD (thrombosis) on affected arteries (3 cases). These changes were visible on successive vascular-imaging (angiographies in 3 cases or MRA in 1); doppler or MRA always confirmed it. These changes appeared early in 3 cases (day 2, 3 and 8) or in subacute stage in 1 (day 15). Anticoagulation was continued for all pts for 3 months. Late course was good with a clinical improvement in all pts. Persistent thrombosis was only observed in one case. C o n c l u s i o n : Mechanisms of early deterioration of CAD are unclear (anticoagulant, etiology). The role of MRA is emphasised in early follow-up, to detect changes of CAD patterns.

P-97 M R I M A G I N G A N D MR A N G I O G R A P H Y V E R T E B R A L A R T E R Y DISSECTION.

OF

Bianchi M.C*, Mascalchi M ~ Mangiafico SA, Scardigli VA, Abbruzzese A *, Canapicchi C*. *Department of Neuroradiology, S.Chiara Hospital, Pisa, Italy. ~ of Clinical Radiology, University of Pisa, Italy. ^Department of Neuroradiology, Careggi Hospital, Firenze, Italy. Purpose: To investigate MR Imaging (MRI) and MR Angiography (MRA) features of vertebral artery dissection (VAD) and to correlate them to the interval time from presenting symptoms. Material and Methods: Serial MRI and MRA examinations on 12 patients (10 males and 2 females aged from 33 to 64 years, mean 47 ) with clinical and X-ray-angiographic evidence of VAD were reviewed. The following features were analyzed: a) brain parenchyma lesions, b) appearance of the dissected vessel on conventional SE T I , P D , T 2 W I and c) on MRA-TOF images. Results: Dissection involved V1 segment in 1 case, V2 in 4, V3 in 3 and V4 in 5. Multiple dissections were noted in 3 cases. Five patients had a solitary latero-medullary infarct; four had multiple brainstem, cerebellar, thalamic or temporo-occipital ischemic lesions, whereas 1 patient presented with SAH, 1 with a fronto insular infarct and in 1 was an occasional finding on the preoperative angiography performed for neoplasm. Dissected vessels appeared as crescent or annular hyperintense wall thickening on T1 W1 in all 8 patients studied between 4-10 days since onset of symptoms. Corresponding PD and T 2 W I were available in 7 patients and showed increased wall signal. In 5 patients follow-up M R I showed

disappearance of the vessel wall hyperintensity with recanalization in only 1 patient and occlusion in the others. On MRA images absence of flow signal at V3V4 segments was in 3 patients; a segmental and an elongated vessel narrowing were separately present in 2 patients. Conclusion: MRI and MRA might provide a non invasive diagnosis of VAD.

Pl98 I M A G I N G OF C A R O T I D A N D V E R T E B R A L DISSECTIONS, C L I N I C A L M A N A G M E N T AND F O L L O W UP OF 27 PATIENTS.

Martin D, Baudouin B, Giroud M, Krause D, Binnert D. Services de Neuroradiologie et de Neurologie H6pital G(n~ral CHU Dijon France. Purpose : Clinical follow up of 27 patients diagnosed as having vertebral and carotid dissections. P r e l i m i n a r y results of MR a n g i o g r a p h y by comparaison with DSA and echo doppler examination. Material and Methods : During a 20 month period we have collected 27 cases of vertebral and carotid dissections. Clinical onset was stroker, TIA, headaches, facial and cervical pain, Claude Bernard Horner syndrom, subarachnoid haemorrhage (SAH) in one case located on the V4 segment. Diagnosis was performed with echo doppler examination, DSA, and MRA using 3D time of flight sequences. Duration of the clinical follow-up ranged from 3 to 24 months. Results : False negative and false positive results of echo doppler examination are reported as well as false negative data from MRA especially in cases of vertebral dissections. Congenital pre existing arterial diseases were recognized in 5 cases (18%). post traumatic dissections including osteopathic manipulations were encountered in 6 cases (22%). Partial recovery of stroke has been registred while non deficitary patients have presented favorable evolution with medical treatment (heparin, acetyl salycilate, platelets antiagregants). C o n c l u s i o n : However clinical symptoms are very various, diagnosis of carotid and vertebral dissections has to be early evocated in order to apply adapted medication. Examination of the upper segment of the internal carotid artery using echo doppler is unreliable and MRA does not reveal all vertebral dissections. On one year angiographic control, we have observed a complete disappearence of carotide false aneurysm. This indicates that surgical or endovascular treatment is not necessary. In an other hand intradural dissection revealed by SAH has to be cured by surgical clipping or endovascular occlusion using detachable balloons.

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P-99 R O L E OF FIBRINOLYSIS IN THE T R E A T M E N T OF ATHEROMATOUS STENOSIS OF C E R E B R A L ARTERIES

P-100 A D V A N C E S IN P E R C U T A N E O U S T R E A T M E N T OF S T E N O T I C L E S I O N S OF T H E C A R O T I D BIFURCATION

Gobin Y.P, Duckwiler G.R, Watson V. V, Vinuela F EndovascuIar Therapy Service. Department of Radiology. UCLA Medical Center. Los Angeles, CA

Theron J., Monteiro G, Payelle G, Coskun O, Toulas P. Department of Neuroradiology and Interventional Radiology, CHU Caen, France

P u r p o s e : T o report the therapeutic implications of diagnosing a clot associated with atheromatous stenosis of intracranial cerebral arteries Material and Methods:Five male patients aged 48 to 75 (mean 68), presented with transient ischemic attacks and/or deficit worsening despite anticoagulant treatment. Superselective intraarterial fibrinolysis was performed with 500-800K IU Urokinase injected immediately below the site of stenosis or occlusion. Angioplasty was performed in one case.In case 1, angiography demonstrated a 80% stenosis of the right intrapetrous internal carotid artery (ICA), with an associated intraluminal clot. Embolization from the clot into the MCA occurred during the angiography. Immediate fibrinolysis resulted in reopening of the MCA, and reduction of the ICA stenosis. In case 2, the left middle cerebral artery (MCA) was occluded on its distal M1 portion. Fibrinolysis resulted in a 80% MCA stenosis, treated by angioplasty resulting in a 40% residual stenosis.In cases 3, 4, and 5, angiography demonstrated a 70%-90% stenosis of the inferior third of the basilar artery, with an intraluminal clot demonstrable in cases 4 and 5. Fibrinolysis resulted in a diminution of the stenosis in case 3, and in a disappearance of the associated clot without modification of the stenosis itself in case 4 and 5. Results:Patients 2, 3, and 4, had no recurrence of their s y m p t o m s and were a s y m p t o m a t i c under anticoagulant therapy at a five to seven month followup. Patient 1 had a moderate sensory deficit. Patient 5 worsened in the days following fibrinolysis and died in one week. C o n c l u s i o n : D i a g n o s i s of clot associated with an intracranial atheromatous arterial stenosis is important because: 1) In case of misdiagnosis, angioptasty of the stenosis can result in potentially devastating embolus. 2) Fibrinolysis may dissolve an intraluminal clot or dissolve the fresh clot component of a tight stenosis, and thus be sufficient to resolve the symptoms without performing additional angioplasty.

P u r p o s e : Because of the hardness and frequent ulceration of the plaque at the carotid bifurcation our experience on carotid angioplasty showed that:l ) a cerebral p r o t e c t i o n during the p r o c e d u r e is mandatory,2) recurrent stenosis occurs in 10% of the cases. Consequently: a- our cerebral protection system has been progressively improved, b- the use of endoluminal stents (Strecker) has become more frequent in sub optimal angioplasty results. Material and Methods : The results are based on an experience of 115 atherosclerotic stenoses treated in 38 cases without cerebral protection, in 77 cases with 4 different types of cerebral protection systems. Results : l) The last system of protection consists in a complete e n d o v a s c u l a r clamping that totally excludes the risk of cerebral embolism. 2) The use of Strecker stents has dramatically reduced the risk of recurrent stenoses. C o n c l u s i o n : Progressive evolution in the technique allows a much safer interventional endovascular approach of the atherosclerotic stenoses of the carotid bifurcation.

P-101 THE TREATMENT OF PROXIMAL (PREVERTEBRAL) SUBCLAVIAN ARTERY STENOSES WITH PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY

Memis A, Diindar C, Memis A, Killi R, Ozbek S, Yunten N , Ozer H Ege University Medical School Dept.of Radiology Izmir, Turkey The purpose of this study is to confirm the color Doppler sonographic diagnosis of the haemodynamic changes in patients having subclavian steal symptoms and to perform the treatment at the same time by means of angiography and angioplasty. Color Doppler sonographic examinations were made in patients referring with complaints such as dizziness and arm pain. In 10 patients, Doppler sonography demonstrated findings of subclavian stenosis (bilateral in two patients ) and vertebral artery flow changes indicating subclavian steal. Then, after necessary arrangements were completed, angiography and angioplasty were made at the same time. In 10 patients, 12 pre vertebral subclavian artery lesions - bilateral in 2 ) were found. They were 2 occlusions and 10 stenoses. For the stenoses ,balloon angioplasties were made. One of the occlusions was treated by recanalization and balloon dilatation only.

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For the other occlusion, following balloon angioplasty, a wallstent was placed, because of an excessive elastic recoil effect. The proximal ( pre vertebral ) segment of the subclavian artery is a common site for obstructive or stenotic lesions. Haemodynamic changes caused by these lesions (Subclavian steal syndrome ) can be diagnosed easily and exactly by color Doppler sonography (A thirty second diagnosis). After the confirmation of this diagnosis by angiography, angioplasty, performed at the same time, is an effective therapeutic procedure with low complication rate, making the quick r e g r e s s i o n of the haemodynamic changes and symptoms possible.

P-102 INTERNAL CAROTID ARTERY OCCLUSIONI N T R A A R T E R I A L T H R O M B O L Y S I S A N D PTA

Bockenheimer St and Mohs C Krankenhaus Nordwest, Frankfurt~Main, Germany Intraarterial thrombolysis of fresh carotid artery occlusion is considered generally as contraindicated as well as percutaneous transluminal angioplasty of this artery is believed to be dangerous at least. We present a 49 y old male patient with completed minor stroke of the right hemisphere caused by occlusion of the right internal carotid artery. He suffered from a sudden onset of aphasia and right hemiparesis and loss of consciousness. DopplerSonography suggested the occlusion of the left internal carotid artery. A n g i o g r a p h y revealed occlusion with a fresh thrombus formation. Because of the life threatening situation we decided to begin with intraarterial thrombolysis. In less than 10 min the thrombus dissolved. A filiform stenosis appeared which was consequently successfully treated with PTA. In the course the patient recovered. This case demonstrates that eventually dangerous therapeutic methods in Neuroradiology should be at hand in the management of acute stroke.

P-103 DIGITIZED DYNAMIC CEREBRAL P A R E N C H Y M O G R A P H Y (DDCP) IN A C U T E AND CHRONIC CEREBRAL ISCHEMIA

Theron J., Payelle G, Huet H, Coskun O, Oliveira G,. Toulas P. Department of Neuroradiology and Interventional Radiology, CHU Caen, France P u r p o s e : Using a contrast injection in the ascending aorta digitised series centred on the head with modified windows clearly demonstrate the actual vascularisation of the cerebral parenchyma. Material and Methods: 4 years of daily routine use of DDCP (more then 1000 cases).

P-01 - P-116 Results: On each case, depending on the pathology, are clearly demonstrated; 1) arterial unilateral delays, 2) circulatory speed modifications, 3) unilateral cortical vasodilatation, 4) unilateral cortical hypovascularisation, 5) parenchymal areas of ischemia. C o n c l u s i o n : Used before and after treating a patient for an acute or chronic cerebral ischemia (thrombolysis, angioplasty, surgery), DDCP provides precise information on the parenchymal vascularisation and the efficacy of the treatment.

P-104 TOMOSCINTIGRAPHIC PROGNOSIS OF NEUROLOGIC STATUS AFTER CAROTID ENDARTERECTOMY IN P A T I E N T S W I T H C H R O N I C C E R E B R O V A S C U L A R DISEASES

Lishmanov Yu., Shvera I, Shipulin V, Plotnikov M, Ussov V. Institute of Cardiology, Tomsk, Russia The aim of this study was to define scintigraphic variable parameters for prognostic changes in neurologic status with surgical treatment of brachiocephalic arteries with stenotic atherosclerosis. The study population consisted of 20 pts with previous ischemic stroke or RIND, undergoing carotid endarterectomy from internal carotid artery. Pts were divided into 2 Groups: Gr 1 - 11 pts with significant positive postoperative changes in neurologic status, Gr 2 - 9 pts with no or negative changes. 8 volunteers were studied as controls. All the pts underwent 99mTc-HMPAO and 99mTc-RBC SPECT. Asymmetry Indices(AI) were calculated for CBF (AIrcbf) and CBV (Alrcbv) tomoslices. IArcbv/IArcbf ratio also was calculated. The results were following: Group 1 Group 2 Control IArcbf 0.93+-0.06 0.96+-0.04 1.00+-0.02 IArcbv 1.09+-0.08 0.84+-0 10" 1.01+-0.03 (IArcbv)/ (IArcbf) 1.16+-0.06 0.86+-0 07* 1.01+-0.02 * p < 0.05 - Gr 2 vs Gr 1 Therefore, prospective results analysis showed, that parameters for prognostic positive changes in neurologic status are pre-operative values of IArcbv and IArcbv/IArcbf > 1. It's likely to associate with increased blood volumes in viable brain tissues with perfusion defect.

S 128 POSTERS P-105 S P E C T - ESTIMATE OF R E O T H E R A P E U T I C A L EFFICACY IN PATIENTS WITH C H R O N I C C E R E B R O V A S C U L A R DISEASES

Shvera I., Ussov V, Kozlov B, Shipulin V, Lishmanov Yu.Institute of Cardiology, Tomsk, Russia P u r p o s e : The aim of this study was to estimate regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) in patients with chronical cerebrovascular disease before and after plasmapheresis (P). M a t e r i a l and M e t h o d s : The study population consisted of 10 pts with stenotic atherosclerosis of brachiocephalic arteries. P was carried out in all pts four times. 8 volunteers were studied as controls. All the pts underwent 99mTc-HMPAO and 99mTc-RBC SPECT before and after P. rCBF and rCBV were calculated. Results: The results were following: After P Control (N-8) Before P (N-10) (N=10) 44.7+-3.1" 53.0+-3.1"* rCBF5 2.1+-2.3 ml/1OOg/mn 5.4+-0.2* 4.8+-0.2** rCBV 4.5+-0.2 ml/1OOg * p < 0.05 - pts before PF vs control ** p < 0.05 - pts after PF vs pts before PF The findings indicate that P promotes to positive change in rCBF and rCBV in patients with chronic cerebrovascular diseases. Therefore, P seems to be a good prevention method for ischemic stroke, when angioplasty is impossible or is not necessary. Thus, SPECT permits to estimate treatment efficacy.

P-106 C O R R E L A T I O N OF X E N O N - C T A N D P E T STUDIES BEFORE AND AFTER A C E T A Z O L A M I D E (DIAMOX R) APPLICATION

Haubitz B., Koch T, *HeibIerH, **Burchert W, *Rickels E, ***Holl K, Becker H. Department Neuroradiology, *Department Neurosurgery, **Department Nuclear Medicine, Medical School. Hannover, FRG ***Neurosurgical Department, Landesnervenklinik Wagner-Jauregg, Linz, Austria Several methods are used for determination of the clinical relevant cerebrovascular reserve capacity. The stable Xenon-CT-CBF-method is relatively easy to carry out. The expensive PET-method is limited to a small number of centres. The Xenon-CT-method is based on transmissiontomographically measured Xenon-uptake in the cerebral tissue. Its resolution is 69 m m (FWHM). The PET-method (6 x 6 x 6 mm FWHM) is using 150-labelled water injected i.v. for e m i s s i o n t o m o g r a p h i c a l l y m e a s u r e m e n t of CBF. Xenon-CT and PET are based on the Kety-Schmidt-

P-O1 - P-116 equation. As both methods were done by different study groups no comparable data are available and clinical reliability has been doubted. This study was performed to compare Xenon CT and PET for CBF measurement, by applying both methods to the same patients. Fifteen patients, 13 males and 2 females, were investigated before and after DiamoxRstimulation. Diagnosis of the carotid arteries were: unilateral stenosis (6 patients), combination of occlusion and stenosis (5 patients); bilateral stenoses (2 patients), bilateral occlusion (1 patient), unilateral occlusion (1 patient). A data reduction was performed because of different time intervals between the CBFstudies in the patients. Only studies with a small time interval (most of them < 1 week) between Xenon-CT and PET measurements were included in a regression analysis (11 patients). Based on the model y=ax comparing the cerebral blood flow values of the hemispheric half slices before and after DiamoxR-stimulation a linear relationship (p<<0,05) was found between Xenon-CT and PEI measurements. The flow data can be differentiated in two groups (WARD clustering method) showing a high flow and low flow variant. In conclusion our data underline the reliability of cerebral blood flow values obtained by Xenon-CT and PET as comparison of both methods in the same patients showed a sufficient correlation.

P-107 E A R L Y D I A G N O S I S OF F O C A L C E R E B R A L I S C H E M I A IN RATS: C O M P A R I S O N OF T H R E E QUANTITATIVE MR-IMAGING T E C H N I Q U E S

Heiland S, Forsting M, Reith W, Sartor K. Dept. of Neuroradiology, University of Heidelberg Medical School, lm Neuenheimer Feld4OO,Heidelberg, Germany Purpose:Diffusion-, perfusion-, and T2 -weighted MRimaging are considered sensitive methods for early diagnosis of focal cerebral ischemia. We wanted to compare the capability of these methods in a rat model. We were particularly interested whether the respective parameters provided independent information regarding the degree of ischemia. M a t e r i a l and M e t h o d s : I n 22 rats ischemia was induced by endovascular occlusion of the middle cerebral artery (MCA). 30-150 minutes after occlusion measurements were obtained on a conventional T1 MR system using a fast T2 -weighted F L A S H sequence for perfusion imaging, a SSFP sequence (b=0-967 s/mm2) for diffusion-weighted imaging, and a FLASH sequence (TE=1838 ms) for T2 -weighted imaging. In user-defined regions the following parameters were calculated: rrCBV, MTT, ADC, and T2 The volume of the ischemic tissue was determined by TTC staining.

S 129 POSTERS Results:Quantitative analysis of the bolus tracking sequence yielded a mean relative decrease of rrCBV in the ischemic region of 37% and a mean difference of the MTT between ischemic and non-ischemic regions of 2.7 s. The mean ADC was 4.6010-4 mm2/s in the ischemic area, whereas it was 5.7910-4 mm2/s in the non-ischemic area. T2 of the ischemic lesion was 4.3 ms longer than T2 in the non-ischemic surrounding brain tissue. No significant correlations existed between these functional parameters. C o n c l u s i o n : O u r results suggest that diffusion-, perfusion- and T2*-weighted MR imaging yields reliable parameters for diagnosis and monitoring of regional cerebral ischemia. With regard to early diagnosis of ischemia these parameters appear to provide independent, complementary informations.

P-108 MR DEPICTION OF F O C A L CEREBRAL ISCHEMIA: USE OF A NEW GADOLINIUM COMPLEX AS C O N T R A S T AGENT FOR PERFUSION-WEIGHTED IMAGING

Heiland S 1, Forsting M 1, Reith W 1, Balzer T 2, Sartor K1 1 Dept. of Neuroradiology, University of Heidelberg Medical School, Im Neuenheimer Feld400, D-69120 Heidelberg, and 2 Dept. of Contrast Media Research, Schering AG, Berlin, Germany P u r p o s e : I n this study we determined the new non ionic contrast agent Gadolinium(Gd)-Butriol in MR perfusion-weighted imaging, including the influence of different concentrations and dosages of this agent on the reliability of perfusion parameters. Material and Methods:In 12 rats ischemic infarction was induced by endovascular occlusion of the middle cerebral artery. Within 35-105 minutes after onset of ischemia all animals were examined on a 1T whole body MR scanner. A fast T2*-weighted F L A S H sequence (Dt=1.96s) was used to acquire 4 images before and 16 images after bolus injection. Each animal received 6 bolus injections consisting of 0.1, 0.3, and 0.5 mmol/kg of Gd-Butriol with two different concentrations (0.5 tool/l, 1 tool/l). From user defined regions of interest (ROls) we obtained the relative regional cerebral blood volume (rrCBV) and the mean transit time (MTT). Results:After bolus injection a significant signal loss could be seen in the non-ischemic regions only for dosages of 0.3 and 0.5 mmol/kg. Administration of the lmol/1 solution yielded a better contrast between the different regions as well as a sharper and higher peak in the concentration-time curve compared with that of the 0.5 tool/1 solution. The mean relative decrease of the rrCBV in the ischemic region was 32%, and the mean difference of the MTT of the ischemic and the non-ischemic region was 3.5s for the 0.5 mol/1 solution and 2.1 s for the 1 tool/1 solution.

P-01 - P-116 C o n c l u s i o n : O u r results show that administration of the contrast agent with a higher concentration yields a higher signal intensity and time resolution and enhances the reliability of measurements of MTT and rrCBV, because the smaller volume of contrast agent allows to produce a sharper bolus. These results are potentially important for perfusion-weighted imaging of the human brain, since the volume of contrast agent may be reduced if a solution with higher concentration is used.

P-109 D I A G N O S T I C IMPACT OF C O M P U T E R I Z E D ANALYSIS ON A N G I O CT

Bartolini A, Gasparetto B, Roncallo F, Furlan M, Trivelli G, Sullo L Institute of Clinical neurology, University of Genova andCNR-Center of Cerebral NeurophysiologyVia De Toni Genova, Italy We analyzed the time-contrast curves and generated three functional images in patients with brain tumors (42), AVMs (10) and ischemia (120). The ischemic patients were further subdivided in a group with a positive CT pattern (60) and a group with negative CT pattern (40). Functional images were assessed modelling timedensity curves and brain local contrast medium distribution volume in two ways: as a labyrinth in which the contrast medium performs a random walk; and as volume composed of two compartments, intravascular and extravascular. The first model allowed us to assess the regional A r m - B r a i n circulation time, rABCT, as the first normalised mathematical moment of the curves about injection time. The second model, distinguishing between contrast changes linear with those of inflowing arteries and contrast changes linear with the integrated arterial changes, according to the multiple time graph analysis described by Patlak, allowed us to generate vascular v o l u m e density, Vv and unidirectional B l o o d Brain Barrier (BBB) permeability images, K.Owing to the excellent spatial resolution of both images, pixel corresponding to different levels of vascular volume were able to be selected. This allowed us to analyze images corresponding to major vessels, using angiographic concepts, a n d to analyze images related to gray and white matter tissue vasculature, using rCBF concepts. In patients with brain ischemia abnormal findings were found in 95 % with a positive CT and in 60% with a negative CT. Combined evaluation of rABCT and V images allowed us to draw qualitative conclusions about blood flow in 80% abnormal regions and about perfusion reserve in 10% abnormal regions. Attempts to obtain a complete diagnosis by assessing two slices were fairly successful and results were in good agreement with carotid angiography

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data.The rate of detection of cerebral tumors by contrast enhancement increased from 68% to 84% furnishing information on tumor vasculature similar to that usually detected with cerebral angiography and discriminating easily between tumors with and without disrupted vascular pattern. In particular, it allowed easy differentiation of meningiomas, glioblastomas and metastases.In AVMs both the occurrence of the lesion and conclusions upon its haemodynamic effects were obtained in all cases.

pill0 R E L A T I O N S B E T W E E N E C H O G E N I C I T Y OF CAROTIDIAN STENOSES AND BRAIN A B N O R M A L I T I E S IN MRI (47 CASES)

Krause D, Martin-Champetier R, Becker F, Beaudouin N, Martin D, Cercueil J.P, Gabrielle F, David M, Brenot R, Walker P, Binnert D, Mabille J.PRadiology Neuroradiology - Vascular Surgery University Hospital - Dijon- France Purpose:Hypoechogeneous or h e t e r o g e n e o u s carotidian stenoses are considered as being more dangerous for the brain because of the potential t h r o m b o - e m b o l i c risks. The h y p o e c h o g e n e o u s character signifies soft material, with intraplaque haemorrhage. The aim of this ongoing study is to investigate the conditions of the brain of symptomatic and also asymptomatic patients, when the carotidian stenosis is detected during a vascular investigation. M a t e r i a l and Methods:Study from march 93 to January 94.Group of 47 patients; men: 33; women: 14; mean age: 66 years. All (47) the patients suffer from severe uni or bilateral stenoses of the internal carotid, detected by Color Doppler. The echogenicity is specified: hypo-anechogenious, hypoechogenious heterogeneous, or isohyperechogenious.MR Imaging of the brain: Axial T2 SE W. sequences: TR: 2500, TE: 40, 120. Criteriae studied: grey substance stroke sequelae, chronic white matter ischaemia, atrophy. R e s u l t s : T w o categories of patients are considered: -Asymptomatic (26), of which 7 have bilateral carotidian stenoses. The hypoechogenious character of the stenosis is clear (21 stenoses).-Symptomatic patients (21), of which 14 suffered from bilateral carotidian stenoses (29 hypoechogeneous stenoses).Bilateral chronic white matter ischaemia (patches) is observed in the two group, asymptomatic (21/26) and symptomatic (19/21).-Atrophy: identical distribution:

P-Ill PREOPERATIVE ASSESSMENT OF T H E V E R T E B R A L A R T E R I E S W I T H S P I R A L CT A N G I O G R A P H Y (CTA)

FarrCs M.T., Magomentschnigg H, GOrzer H, Schindler E Department of Angiography and Interventional Angiography and Department of Neuroradiology, University Hospital, Vienna, Austria. Purpose: CTA was used to obtain a morphologically adequate imaging of the proximal sections of the vertebral arteries. This imaging was carried out as preoperative contribution to planning vertebraliscarotid transposition. Materials and Methods: 15 patients with vertebrobasilar insufficiency underwent four vessel angiography as well as CTA before planning vertebralis-carotid transposition. CTA was performed with a Somatom Plus S (Siemens): intravenous administration of 120 ml contrast medium (4 ml/sec), scan delay: 24-38 sec; continuous table feed: 2-3 mm/sec, slice thickness: 2-3 ram. Maximum intensity protection and surface shaded display were used for post processing. R e s u l t s : Compared to the operative findings, the proximal sections of the vertebral arteries were adequately visualised with CTA. Since vessel overlying can be avoided, CTA provided with more information than angiography concerning stenoses near the origin of the vertebral artery. Vessel tortuosity was clearly visualised with CTA. Calcification of the vessel wall could be ascertained with the maximum intensity protection program. Conclusion: CTA proved to be a very helpful imaging modality that provides with significant information about vessel morphology. It can be used, therefore, in addition to angiography (or even replace angiography) when vertebral-carotid transposition is planned.

P-112 SPIRAL ANGIO-CT ARTERIES

OF C I R C L E OF W I L L I S

Ricolfi F., Brugi~res P, Combes C, Khalil A, Sadik J.C, Gaston A H@ital Henri Mondor, Cr6teil, France Purpose:Compare Spiral angioCT and conventional angiography to visualise circle of Willis arteries Material and Methods:Spiral CT (Elscint CT Twin) of circle of Willis with 60 cc intravenous injection of contrast media and conventional angiography of intracranial circulation were performed in 20 patients. Helix parameters were: length 46 ram; thickness lmm, pitch 1.5, time 29 s. Both MIP and 3D surfacic reconstructions were performed. Results:9 cases had normal angiograms, 10 intracranial aneurysms and 1 cavernous sinus tumor

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POSTERS MIP reconstructions could correctly depict portions of circle of Willis above anterior clinoid process level. 3D surfacic reconstruction was useful when arteries were closed to bone structures and allowed better delineation of giant aneurysms Conclusion:3D spiral angio CT of circle of Willis can be performed routinely for circle of Willis exploration Both M I P and surfacic 3D reconstruction are necessary and c o m p l e m e n t a r y to depict normal anatomy and aneurysms.

P-113 CAROTID ARTERY STENOSIS: EFFICACY OF SPIRAL CT WITH 3D SURFACE SHADED AND M.I.P. IMAGES Blum A, Bazin C, Boccaccini H, Rodde A, Delfau F, Claudon M, Rdgent D.

Purpose: to compare spiral CT and surface 3D and MIP images with selective catheter angiography for evaluating carotid artery stenosis. Material and Methods: 15 patients (30 bifurcations of the commun carotid artery) underwent spiral CT and selective angiography of the carotid arteries. Spiral CT were obtained with a Somatom Plus S scanner (Siemens), using a 3-mm-thick collimation, a 3-mmlsec table feed, reconstruction of overlapped images and a total scanning time of 30 sec. 1.30 ml of sodium oxitalamate (Telebrix 30, Guerbet) were injected into an antecubital vein at the rate of 3 mVsec. The acquisition was performed without altering the patient's breathing pattern. Subsequently, surface 3D and MIP images were performed. The CT scan and angiograms were evaluated randomly by two radiologists and axial images, surface 3D and MIP images were compared to angiograms using the Kappa test. There was a very strong agreement between axial images and angiogram and between surface 3D images and angiograms in the evaluation of artery stenosis. There was a poor agreement between MIP images and angiograms. Calcifications were better detected with MIP than with surface 3D images. C o n c l u s i o n : Spiral CT is an accurate and non invasive method to explore carotid artery bifurcations. MIP image helps interpretation of surface 3D images by showing the calcifications.

P-114 R A D I O L O G I C A L D I A G N O S I S OF BRAIN DEATH: DIGITISED DYNAMIC CEREBRAL PARENCHYMOGRAPHY (D.D.C.P). Huet H, Leroy G*, Theron J. Department of Neuroradiology and interventional Radiology*Surgical Intensive Care Unit.Caen CHU Caen France

P-01 - P-116

P u r p o s e : The aim of this preliminary study is to evaluate the D.D.C.P. in patients with state of brain death. When sedative drugs used in intensive care units, the electroencephalograms become uninterpretable, and consequently the arrest of intracerebral circulation is mandatory for the cases of brain death. Material and Methods: 11 patients (6 males and 5 females including 2 children (6 and 8 years)) underwent digitised intraarterial cerebral parenchymography. In all 11 patients the classical clinical signs of cerebral death were present, and all of them received sedative drugs. Frontal and lateral serials views were obtained. Results: In all patients two criteria were observed: 1absence of cerebral parenchymogram resulting from opacification of the internal carotid artery and the vertebrobasilar artery systems.2-opacification of the external carotid artery branches in the scalp. Conclusion: D.D.C.P. is a simple and fast technique that does not alter physiological conditions and provides unequivocal and high quality images of brain death. Fast and accurate decisions may therefore be obtained for optimal organ transplantation.

P-115 INTRAVENOUS ANGIOGRAPHY AS AN AID FOR DIAGNOSIS OF BRAIN DEATH.EXPERIENCE ABOUT 125 PATIENTS. Braun M. *, Anxionnat R. *, Claise B. *, Ducrocq X. ~, Pincemaille B **,Hepner H. ** Picard L. * Department of Neuroradiology*, Neurosurgery **and Neurology ~ St Julien - CHU Nancy-France Purpose : The diagnosis of cerebral death is submitted to several conditions. Clinical determination of death requires irreversible cessation of all functions of the entire brain, including the brain stem. Imaging may be used for establishing the cause of the coma, may be desirable when objective documentation is needed to substantiate the clinical findings or in order to shorten the period of observation required for the organs donation. Among other techniques, the intravenous four vessel angiography may help to confirm the clinical diagnosis and to establish the cessation of cerebral blood flow. Material and Methods : 125 patients with suspected brain death by clinical examination were studied. Venous vascular injection was performed through a brachial or femoral vein as jugular or subclavian accesses were responsible for massive jugular and dural sinus reflux. 60ml of contrast material were injected at a flow rate of 12-15 ml/sec. Lateral only or simultaneous AP and Lateral views were obtained in all cases for a filming sequence of 60 seconds. Results : According to the angiographic findings, we classified the patients into four groups. Group 1 (85%)

S 132 POSTERS

the angiography demonstrates the cessation of blood flow occurring at the V3-V4 junction of the vertebral arteries and at different levels of the internal carotid (cervical portion(44%)-C1 portion of the carotid siphon (53 %)- anterior or middle cerebral arteries (A1 or M1) (3 %). The filling of the anterior and/or middle cerebral arteries was slow and concerned the first portions of these arteries. In group 2 (9,6%) 12 patients presented with a vascular stasis of contrast material within the basilar artery or the posterior cerebral arteries without evidence of flow, associated with cessation of flow at C1 level of the internal

P-O1 - P-116

carotid artery. Group 3 consists of 7 patients (5,6 %) who mey a persistent blood flow (with a very slow and delayed venous drainage within the posterior fossa) and a cessation of flow at different internal carotid arotid levels. The remaining case (Group 4) was a true false negative diagnosis of brain death under angiographic criteria.(previous craniotomy for acute subdural haematoma). In all cases, angiographic aspects were correlated to the clinical status, the EEG and or transcranial doppler findings before pronouncing the brain death.