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Results: Between 1988 and 2001, total CTs increased from 17,000 to 71,000, and pediatric CTs from 1,200 to 2,900, whereas all imaging studies increased from 244,000 to 448,000 and all pediatric studies from 22,000 to 31,000. While the proportion of pediatric studies decreased from 7.1 to 6.9 % from 1995 to 2001, the proportion of pediatric CTs increased from 6.0 to 9.4 % (P<0.001). The sharpest increase in pediatric CTs has been in studies of abdomen, pelvis and chest, whereas the proportion of head and neck studies has decreased, and extremity CT utilization has remained relatively stable. Conclusion: Pediatric CT utilization has increased substantially during the past decade, both in absolute and relative terms, particularly in the chest and abdomen. These data, in combination with published age and gender-specific risk estimates and our ongoing institutional radiation dose survey, as modulated by the use of pediatric dose reduction protocols since 1999, will allow populationbased cost-effectiveness estimates for CT.

Results: While W/Wn was 1.53 ± 0.27 in females, and 1.49 ± 0.20 in males, BMCt/BMCtn, L/Ln and F/Fn were 1.12 ± 0.11, 1.25 ± 0.20, and 2.12 ±0.52 in females, 1.07 ± 0.10, 1.14 ± 0.12, and 2.34 ± 0.51 in males. F/Fn and L/Ln were moderately correlated with W/Wn (r2 ¼ 0.65–0.47, and 0.41–0.28, respectively, in females and males), BMCt/BMCtn was poorly correlated with this parameter (r2 ¼ 0.39 in females, and 0.13 in males). Conclusion: The alterations in L and F differed in males and females. Moreover, the increase of BMCt is rapidly limited to approximately 10 % in both sexes.Clinical images to be shown : DXA scans and results. Normal value curves.

SCIENTIFIC EXHIBITS NEUROIMAGING

97 BONE MINERAL DENSITY (BMD) IN SURVIVORS OF CHILDHOOD BRAIN TUMORS Sue C. Kaste, DO, St. Jude Children’s Research Hospital, Memphis, TN; Mark V. Sapp, MD; Tami J. Shidler, RN; Lisa Dillard; Xiaoping Xiong, PhD; Junhong Zhu, MS; et al Purpose: Cancer treatment, inadequate nutrition, sedentary lifestyle, secondary neuroendocrine and neurologic sequelae predispose pediatric brain tumor survivors to bone mineral deficits. Methods and Materials: After IRB approval, we retrospectively reviewed medical records of 72 patients treated and followed at our institution. We correlated lumbar spine QCT BMD results with clinical parameters including age at diagnosis, gender, race, cancer treatment, endocrinopathy and neurologic deficits. Results: Forty-four (55 %) were female; median age at diagnosis 6.48y (range 0.49–19.84y); 29 were treated for medulloblastoma (36.25 %). Mean age at time of study 14.17 y (range, 4.3–25.98y). Median time from diagnosis was 6.31y (range, 0.02–17.39 y). Mean BMD z-score was )1.389 (SD=1.579; SE=0.186), significantly decreased compared with normal values (P<0.00001). Fifty-one (64.56 %) had endocrinopathies. Normal ambulatory function was present in 58 (72.5 %); 10 (12.5 %) had ataxic gait; nine (11.25 %) ambulated with assistance; one used wheelchair or crutches and one used a leg brace. Conclusions: Children and adolescents who have survived treatment for childhood brain tumors have significantly decreased BMD placing them at significant risk for fracture, particularly when associated with falling resulting from of gait instability and seizures.

98 BONE MINERAL CONTENT AND BODY COMPOSITION IN OVERWEIGHT HEALTHY ADOLESCENTS Pierre M. Braillon, PhD, MD, Pediatric Imaging, Hospital Debrousse, Lyon, France; Adrian Serban, MD Purpose: To assess the bone mineral content and body composition in lean and fat masses in overweight youths, and to compare the measured values with normal data. Materials and methods: We studied 227 patients (139 females, 88 males) aged 4.4–18.0 years. The actual weights (W) ranged from 28.1 kg to 115.3 kg in the females (BMI: 27.9 ± 5.7), and from 29.0 kg to 134.5 kg in the males (BMI: 27.1 ± 3.7). A total body scan was obtained on a XR-36
DXA system (Norland Medical Systems, Fort Atkinson, Wi). The measured values of the total bone mineral content (BMCt), lean mass (L), and fat mass (F) were compared to their corresponding normal values, BMCtn, Ln, and Fn, calculated for the normal weight for the actual height of the patients (Wn).

1 SPATIOTEMPORAL MAPPING OF CEREBRAL MATURATION IN CHILDHOOD USING 2D MAGNETIC RESONANCE SPECTROSCOPIC IMAGING (MRSI) – PRELIMINARY REPORT Patrick Barnes, MD, Radiology, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA; Jamie Dermon, SMS1; Dan Spielman, Ph.D Purpose: Assess 2D MRSI for spatial and temporal mapping of cerebral maturation in early childhood. Materials and Methods: Eleven children (1 day to 9 years postterm age) with normal neurodevelopment had 2D MRSI at 1.5T. Regions of interest (ROI) for MRSI were selected from T2 images for (1)the basal ganglia and anterior limb of the internal capsule, (2) the thalami and posterior limb of the internal capsule, (3) occipital lobes, and (4)the frontal to parietal white matter using the PRESS method (TR 1500ms, TE 144ms, 10mm slice, 24cm FOV, 16x16 matrix, 2 averages, 2.25cc voxel). Peak areas, ratios, and maps for n-acetyl-aspartate (NAA), choline (Cho), myoInositol (mI), and creatine (Cr) were calculated using GE FuncTool software on a SunSparc workstation. Comparisons were made with conventional MRI and diffusion tensor (DTI). Results: Analysis shows the following trends regarding a spatiotemporal cerebral maturation gradient: increasing NAA/Cho and NAA/Cr, plus decreasing Cho/Cr and mI/Cr with age as well as caudal to cephalad, central to peripheral, and posterior to anterior. Spatial and temporal metabolite variations were similar but not identical to myelination patterns as determined from T2 and DTI. Conclusions: MRSI maturation criteria probably reflect a combination of myelination, neuroaxonal development, and synaptogenesis. Thus, quantitative MRSI may provide new insights into cerebral maturation.

2 STUDY OF WHITE MATTER MATURATION FROM BIRTH THROUGH ADULTHOOD USING HIGH b VALUE DIFFUSION WEIGHTED IMAGING Dafna Ben Bashat, PhD, The Wohl Imstitute for Advanced Imaging, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; Liat Ben Sira, MD; Moshe Graif, MD; Elka Miller, MD; Talma Hendler, MD, PhD; Yaniv Assaf, PhD; et al White matter (WM) maturation is an important part in brain development and continues from birth through adulthood. High b value diffusion weighted imaging using q-space analysis was shown

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to be sensitive to WM maturation in rats as well as to WM disorders in humans. Fifteen subjects were examined in this study, from premature infant (36 weeks) up to 23- year old, using 1.5 Tesla MRI system. Displacement and probability images were analyzed from the diffusion data. Increase in probability and decrease in displacement values was observed showing major changes with age. Changes were also observed during adulthood showing more then 17 % changes between the groups of 9–11 years and 22– 23 years. ROI analysis demonstrates changes in white matter signal over a long period of life. Changes in signal were observed from birth up to: 6–8 years in the internal capsule, 9 years in the external capsule, 5–6 years in the corpus callosum, 11–15 years in the centrum semiovale and up to adulthood (23 years) in the subcortical white matter. This method was found to be very sensitive to white matter maturation and can be clinically valuable in diagnosing various white matter disorders in children even when conventional MRI appears unremarkable.

separated in left hemisphere, but were overlapped in the right hemisphere. Conclusion: Somatosensory evoked magnetic field was very reliable and reproducible in children. We believe that MEG is not only very useful for localizing the somatosensory cortex, but also very powerful in the investigation of the development and plasticity of brain cortex.

3 VALUE OF LATERAL SCOUT VIEW ON PEDIATRIC HEAD CT

We evaluated if crossed-cerebellar diaschisis (CCD) on SPECT scans could identify laterality in epileptic patients.Thirty-three patients underwent SPECT studies for pre-surgical evaluation of refractory epilepsy. Thirteen underwent both ictal and interictal scans. SPECT images were assessed visually to establish if CCD, either ictal crossed-cerebellar hyperperfusion (CCHR) or interictal cross-cerebellar hypoperfusion (CCHO), contributed to the localization of seizure foci. Cross-sectional histograms across the cerebellum were obtained to establish asymmetry indices (AI).CCD was observed in 17 (45 %) patients, 13 of which were concordant with clinical and SPECT localization. Two of 3 patients with nonlocalizing clinical evaluations presented normal SPECT, while ipsiliateral-cerebellar hypoperfusion was observed in 2 interictal scans. Ictal CCHR was equalized in 4 of 5 patients in their interictal scans, while interictal CCHO was observed in the remaining patient. Semiquantitative analysis revealed that only 13 of 17 patients visually identified presented AI>10 %. Ictal CCHR correctly identified seizure side in 2 patients. Seven of 11 patients with interictal CCHO correctly identified seizure side. Out of the remaining 4 with interictal CCHO, 3 were non-localizing by clinical standards, while 1 presented ipsilateral-cerebellar hypoperfusion. Ictal and interictal CCD may aid in the identification of epileptic foci.

Seyed A. Emamian, MD, PhD, Department of Diagnostic Imaging and Radiology, Childrens Hospital National Medical Center, Washington, DC; Elizabeth C. Dubovsky, MD; Gilbert L. Vezina, MD Purpose: The lateral scout view (LSV) of head is routinely obtained as part of a head CT. Focused evaluation of LSV provides additional, sometimes valuable, information that will not be demonstrated on the axial images. To illustrate this, we present a series of cases that we have encountered. Material and method: The poster includes the studies in which the information on the LSV of the CT scan of the head altered or may have altered the patient management. Results: The cases include a foreign body in carotid artery, vertebral body destruction, an esophageal foreign body, fractures/ pseudofractures and disconnected VP–shunts. These cases constitute approximately 0.5 % of 1000 patients from emergency room that were referred for head CT. Conclusion: The LSV of a head CT should be routinely examined for potentially valuable information that is not available on examination of axial images.

4 VOLUMETRIC LOCALIZATION OF SOMATOSENSORY CORTEX IN CHILDREN USING SYNTHETIC APERTURE MAGNETOMETRY Jing Xiang, M.D., Ph.D, Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada; Sylvester Chuang, M.D.; Stephanie Holowka; Paul Babyn, M.D.; Hiroshi Otsubo, M.D.; Rohit Sharma; et al Purpose: Using magnetoencephalography (MEG) to localize the three-dimensional functional area of somatosensory cortex in children. Materials and Methods: 20 children have been studied using 151 whole cortex MEG system with electrical stimulation applied to left or right median nerves. The location of magnetic response was calculated using both single dipole modeling and synthetic aperture magnetometry (SAM). The exact location was analyzed by overlapping dipole and SAM data on magnetic resonance images (MRI). Results: One response was consistently identified in children (90 %, 18/20). Both dipole and SAM peak localized in the hand area of the somatosensory cortex. Two frequency bands, 30–60 Hz and 60–120 Hz were related to somatosensory cortex. The two groups of the neurons related to 30–60 Hz and 60–120 Hz bands were clearly

5 THE DIAGNOSTIC VALUE OF CROSSED CEREBELLAR DIASCHISIS ON ICTAL AND INTERICTAL BRAIN SPECT IN CHILDREN WITH REFRACTORY EPILEPSY Victor L. Villemagne, MD, The Children’s Hospital of Philadelphia, Philadelphia, PA; Dennis Dlugos, MD; Fabio Ponzo, MD; David Beauchemin, CNMT; Teresa Zaffino-Nevrotski, CNMT; Martin Charron, MD

6 SENSITIVITY OF ICTAL AND INTERICTAL BRAIN SPECT FOR THE DIAGNOSIS OF FOCAL EPILEPSY AT CHOP Victor L. Villemagne, MD, The Children’s Hospital of Philadelphia, Philadelphia, PA; Dennis Dlugos, MD; Fabio Ponzo, MD; David Beauchemin, CNMT; Kevin Edwards, CNMT; Martin Charron, MD Ictal perfusion SPECT scans localize epileptic foci in approximately 90 % of cases. We compared the sensitivity of interictal to ictal SPECT scans in localization of the seizure focus in patients with refractory epilepsy.Retrospective analysis was performed on 36 patients who underwent SPECT scans for pre-surgical evaluation of refractory epilepsy. Two independent observers visually evaluated interictal and ictal scans for focal perfusion abnormalities.Seventeen of 36 patients underwent both interictal and ictal SPECT. Epileptic foci were found in temporal (n=16), frontal (n=10), parietal (n=3), and occipital (n=2), areas. Five patients presented normal scans.Eleven of 15 scans with ictal hyperperfusion correctly localized epileptic focus, while 1 failed to show hyperperfusion and 1 wrongly identified the seizure focus. Seventeen of 24 scans with interictal hypoperfusion correctly localized epileptic focus. Four patients with non-localizing clinical evaluations

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showed normal scans, while 7 scans with localizing clinical evaluations were either normal or wrongly identified the focus.The sensitivity of ictal and interictal SPECT was 72 % and 92 %, respectively.Ictal SPECT is the most sensitive and reliable technique in localizing epileptogenic foci in patients with refractory epilepsy. Greater sensitivity may be achieved by associating ictal SPECT with interictal PET-FDG.

7 EFFECTS OF ATTENUATION CORRECTION ON ICTAL AND INTERICTAL BRAIN SPECT SCANS Victor L. Villemagne, MD, The Children’s Hospital of Philadelphia, Philadelphia, PA; Dennis Dlugos, MD; Fabio Ponzo, MD; David Beauchemin, CNMT; Teresa Zaffino-Nevrotski, CNMT; Martin Charron, MD The purpose of this study was to evaluate the usefulness of attenuation correction (AC) of brain SPECT in children as compared to non-attenuation correction standard reconstruction (NAC).We evaluated brain SPECT scans of 43 patients (57 SPECT scans) who underwent pre-surgical evaluation of refractory epilepsy. Data were reconstructed by filtered backprojection with and without AC. Both AC and NAC SPECT images were analyzed by visual interpretation and count profiles were obtained across the striatum to obtain asymmetry indices (AI) and cortical-subcortical ratios (CSR).When compared with NAC images, AC images showed a better definition of all brain structures, specially deeper cortical and subcotical structures, such as striata, thalami, hippocampus and amygdala. CSR were lower on AC images than in NAC scans method (1.08 +/) 0.21 < 1.22 +/) 0.22 p < 0.01) due to underestimation of striatal perfusion in the NAC images. AI in AC scans were higher in 47 of 57 scans (82 %) due to better contrast between normally and abnormally perfused areas.Attenuation corrections improves image contrast allowing better identification of abnormalities on brain SPECT in children.

MUSCULOSKELETAL IMAGING 8 THE NUMEROUS CLINICAL ENTITIES ASSOCIATED WITH PUNCTATE EPIPHYSES: FROM A TO Z Stephen F. Miller, MD, Hospital for Sick Children, Toronto, ON, Canada; Marilyn D. Ranson, MD; Paul S. Babyn, MD For most pediatric radiologists, the differential diagnosis of punctate, stippled epiphyses is limited to a few entities, usually Conradi-Hunermann syndrome, Zellweger syndrome, and hypothyroidism. However, the list of conditions associated with epiphyseal punctate calcifications is actually quite extensive, and includes teratogenic exposures, chromosomal trisomies and deletions, antenatal infections, endocrine abnormalities, and isolated single-gene defects.Calcific epiphyseal puncta are invariable in some disorders and are only occasionally seen in others. Their presence denotes focal pathological, premature calcification of epiphyseal cartilage. Affected bones may demonstrate abnormal, stunted growth or may develop normally, depending on the underlying disorder. The pattern of calcific puncta, along with the presence or absence of associated ossific and nonossific abnormalities, may suggest a specific clinical entity in many cases. This pictorial essay depicts common and uncommon conditions associated with stippled epiphyses and offers suggestions for radiological differential diagnosis.

9 MY ACHING BACK: A SERIOUS COMPLAINT IN CHILDREN Vesna M. Kriss, MD, University of Kentucky Medical Center, Lexington, KY Back pain in adults is a common and usually benign problem. However, back pain is a serious complaint in children and needs to be imaged aggressively. In children less than 10 years of age, serious causes of back pain such as infection or malignancy were noted in 20–30 % of cases. Traumatic lesions can be subtle, particularily repetitive stress injuries in adolescent athletes. SPECT bone scan of the spine can reveal subtle areas of injury that are not detected on conventional planar bone scans or radiographs. Persistent back pain in a child may signal the presence of bony lesions such as osteoblastoma, neurofibroma or Langerhans Cell Histiocytosis. Discitis is a concern in the pediatric population and early detection by MRI may prevent contiguous vertebral osteomyelitis.Malignancy should also be considered since vertebral involvement may be the presenting sign of leukemia/lymphoma, primary neoplasm or metastatic disease (commonly from neuroblastoma).

10 THE ANGLED BUCKLE FRACTURE IN PEDIATRICS (A FREQUENTLY MISSED FRACTURE) Jose A. Hernandez, M.D., University of Texas Medical Branch, Galveston, TX; Eric P. Hendrick, M.D.; Leonard E. Swischuk, M.D.; David A. Yngve, M.D.; Kelly D. Carmichael, M.D. Buckle fractures which do not produce actual outward buckling of the cortex, but rather subtle angulation of the cortex are easily missed. However, they are important and tend to more commonly occur at certain sites. These, for the most part, include the: proximal radius, distal radius, distal tibia, small bones of the hands and feet, and then the distal humerus and proximal tibia. Often these fractures are isolated and without comparative views easy to overlook. However, once one becomes familiar with their appearance and where they are most likely to occur, they are diagnosed with more certainty. This presentation deals with the mechanism by which these fractures are sustained and how to detect them with certainty. The use of comparative films is emphasized.

11 IMAGING OF ACETABULAR INJURY IN CHILDHOOD Bradley A. Maxfield, MD, Radiology, Children’s Hospital of Wisconsin, Milwaukee, Wisconsin; Robert G. Wells, MD; John R. Sty, MD Injury to the acetabulum and its triradiate cartilage is rare in the spectrum of pediatric skeletal trauma. However the consequences of injury are profound and sequelae may lead to disability. Radiographs are the initial screening study and continue to be sensitive in the detection of pelvic fractures. Computed tomography is very useful in the evaluation of the acetabulum. Orthogonal planar CT images and reconstructions are very sensitive to fracture lines. Three-dimensional CT representations are invaluable for quickly and accurately assessing the gross morphology and geometry of displaced fracture fragments.The viewer of the poster will review the evaluation of standard and supplemental radiographs of the pelvis, Judet classification, CT protocols and post processing, and orthopedic management of pediatric acetabular injury.Images: Aproximately 25 images of 10 patients including plain film, CT, and 3D reconstructions of various types of acetabular and triradiate injury.

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12 NEW HORIZONS IN ANGIOGENIC-RELATED IMAGING METHODS FOR CHARACTERIZATION OF THE CAUSE (SYNOVITIS) AND CONSEQUENCE (CARTILAGE DEGENERATION) OF ARTHRITIS IN AN ANTIGEN-INDUCED EXPERIMENTAL MODEL: A LINKAGE BETWEEN ANATOMIC AND FUNCTIONAL IMAGING Andrea S. Doria, MD, Hospital for Sick Children, Toronto, ON, Canada; Paul S. Babyn, MD; Tammy Trayner, MRT; Mary Anconam, MRT; Maria Mendes; Stuart Foster, MD; et al Functional imaging is a newly emerging field in which modern imaging modalities are being married to state-of-art technology for non-invasive or minimally invasive imaging. This new technology should lead to a considerable enhancement in the study of biological processes and in the management of angiogenic-related diseases such as rheumatoid arthritis.The goals of this exhibit are: 1) to become familiar with new imaging modalities for evaluation of arthritis in a rabbit model such as dynamic (perfusion) MR imaging, BOLD MR imaging, contrast-enhanced gray-scale harmonic sonography, CT angiography and high-resolution (50 MHz) US according to the time course of the arthritic process.2) to demonstrate the linkage between anatomic (CT angiography / histologic specimens) and functional imaging (dynamic and BOLD MR imaging, contrast-enhanced sonography) related to the etiopathogenic process of arthritis (synovitis) at different time points (4,10,24,48 hours, 7,14,21,28 days from induction of arthritis).3) to show the relationship between the cause (synovitis) and the consequence (cartilage degeneration demonstrated by high-resolution US/histologic specimens) of the arthritic process at each time point 4) to help understand the functional imaging findings on the light of known physiologic and biochemical effects of arthritis along the course of the disease. (The Definity contrast agent vials were provided by Dupont Pharmaceuticals, Boston, MA at no costs for research purposes. No other financial interests are present.)

13 EVALUATION OF THE CLUBFOOT BY ULTRASOUND Khaldoun Koujok, MD, University of Michigan Medical Center, Ann Arbor, MI; Lawrence R. Kuhns, MD; Clifford L. Craig, MD The purpose of this exhibit is to show our experience in using ultrasound to evaluate clubfoot deformity in children.There are several advantages of using ultrasound for clubfoot in children - (1) ultrasound can show the un-ossified cartilage of the tarsal bones, (2) ultrasound can evaluate dynamic relationships when stress is applied, (3) no ionizing radiation is required, and (4) no sedation is required. On ultrasound, the cartilage of the navicular and medial malleolus are well seen. We measure the distance between the medial malleolus and navicular and the width of the mid-subtalar joint with and without stress. With stress, we also evaluate for dorsal subluxation of the navicular, lateral subluxation of the cuboid and movement of the talus in respect to the tibia. We use color Doppler to evaluate for presence of the dorsalis pedis artery. Serial ultrasound is used in follow-up to evaluate the efficacy of treatment.In this exhibit, we will illustrate the ultrasound appearance of normal feet and clubfoot deformity, showing how stress is applied and delineating the effect of treatment. Correlative photographs showing the position of the transducer on the foot will be included to orient the viewer.

14 WITHDRAWN

15 RICKETS? Sridhar Gibikote, DMRD, DNB, Department of Radiodiagnosis, Christian Medical College Hospital, Vellore, Tamil Nadu, India In a developing country as India, nutritional rickets is fairly common. The pre-test probabiltiy is very high for a child presenting with widening of the wrists, widening of anterior ribs and ‘double’ malleoli. Initial investigations then asked for are a plain radiograph of the wrists, Serum Calcium, Phosphorus, and Alkaline Phosphatase. We recently came across two children with similar clinical presentation, which were not rickets. One was SEMD – Dominant Metatropic, and the other was Pseudoachondroplasia. Images of the wrists, spine and pelvis of both cases will be presented, along with those of a classical rickets.

RESPIRATORY IMAGING 16 IMAGING ASSESSMENT OF INFANTILE ADENOID TISSUE IN TODAY’S WORLD Gerald A. Mandell, MD, Medical Imaging, A.I. duPont Hospital for Children, Wilmington, DE Purpose: To demonstrate a significant increased volume of nasopharyngeal adenoid tissue in infants less than 6 months, a change from the original reporting of sparse amount of tissue secondary to protection by maternal humoral antibodies by Kirkpatrick and Capitanio in 1970. Materials and Methods: A preliminary study was performed on 32 infants (34 studies) less than 6 mos. of age in 1999 with determination of amount of nasopharyngeal adenoid tissue by measurement on midline sagittal T1 weighted images. The measurement was performed from the sphenooccipital synchondrosis vertically through the nasopharyngeal soft tissue. Results: In 1970 on lateral neck radiographs the presence of adenoid tissue >0.5 cm as 0 % in infants >1 mo. of age, as 1 % in infants 1–3 mos., and 32 % in infants 3–6 mos. The presence of adenoids >0.5 cm were determined on sagittal T1 weighted MR images to be 27 % in infants >1 mo. of age, 64 % in infants 1–3 mos. and 73 % in infants 3–6 mos. Conclusion: The change in time of appearance of the adenoids in infants in thirty year span may be related to the increased presence of pollutants and allergens in the environment. Radiologists and clinicians should be aware of this finding so that the presence of physiologic adenoid tissue is not mistaken for tumor in the nasopharynx.

17 BRONCHIAL DISEASES AND LUNG AERATION IN CHILDREN Sandra S. Kramer, M.D., Radiology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania; Neha A. Kothari, MD; Peter J. Hurh, BS; Richard I. Markowitz, MD Bronchial pathology is common in children and is usually associated with aeration disturbances. The bronchi can be directly imaged down to a diameter of approximately 1.5 mm by CT techniques. Information about the peripheral airways beyond those structures resolvable by CT can be gained from assessment of CT lung attenuation. This exhibit will review developmental anatomy of the tracheobronchial tree, airway physiology unique to small children, and special CT imaging techniques for the pediatric airway. Pathologic examples will include: 1) congenital anomalies: pulmonary agenesis, hypogenetic lung syndrome, tracheal bronchus, bronchial atresia, bronchogenic cyst, and congenital lobar emphy-

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sema; 2) obstructing lesions: foreign body and intrinsic/extrinsic masses; 3) bronchiolitis and asthma; 4) bronchiectasis; and 5) bronchiolitis obliterans.

18 COMPUTED TOMOGRAPHY OF DEVELOPMENTAL PULMONARY ANOMALIES Bradley A. Maxfield, MD, Radiology, Children’s Hospital of Wisconsin, Milwaukee, Wisconsin; Robert G. Wells, MD; John R. Sty, MD Abnormalities that affect the lung may be categorized as either congenital or acquired. The congenital anomalies are many and varied. The more common congenital tracheobronchial abnormalities that have clinical significance are pulmonary hypoplasia, congenital lobar emphysema, congenital cystic adenomatoid malformation, broncho pulmonary sequestration, bronchogenic cyst, pulmonary arteriovenous malformation, and unilateral hypogenetic lung syndrome. These anomalies should be considered as a spectrum of developmental aberrations of the pulmonary parenchyma and pulmonary vessels or a combination of both. They may also be considered part of a sequestration syndrome, because these lesions are separated from either the bronchial system, the pulmonary arteries or the pulmonary veins, in some manner. The clinical presentation of these anomalies can overlap and more than one anomaly may be present. This exhibit demonstrates the distinctive radiologic features of these basic embryologic defects with an emphasis on state of the art multiplanar reformatted, three dimensional, and high-resolution CT techniques.

19 PRIMARY PULMONARY TUBERCULOSIS IN PEDIATRICS AT THE TURN OF THE CENTURY Susan D. John, MD, UT Houston Medical School, Houston, TX; Lawrence H. Robinson, MD; Maria–Gisela Mercado-Deane, MD Primary tuberculosis remains an important cause of acute respiratory illness in children despite advances in infection control and treatment. Symptoms are often mild and nonspecific, but more severe disease due to hematogenous spread is not rare and resistant forms of the disease are increasing. We reviewed the clinical and radiologic findings in 81 children and adolescents diagnosed with tuberculosis at our institution during the past 10 years to determine whether the patterns of imaging findings are changing. This presentation illustrates the common and atypical radiographic signs of primary pulmonary tuberculosis in young patients, with emphasis on the importance of unilateral hilar and mediastinal adenopathy. The value of CT in diagnosis is discussed. Included are examples of unusual imaging presentations in immunocompetent children, such as congenital tuberculosis and atypical miliary disease. Complications due to airway obstruction (e.g., severe pneumatocele formation, atelectasis), pleural effusion, and hematogenous spread are also demonstrated.

20 OPTIMIZATION OF CONTRAST ENHANCED MULTISLICE CT IN PEDIATRIC CHEST: PRELIMINARY EXPERIENCE IN THE ROUTINE STUDY AND CT ANGIOGRAPHY Kazutoshi Fujita, M.D., Radiology, Kanagawa Children’s Medical Center, Yokohama, Japan; Noriko Aida, M.D.; Kazuo Endou, R.T. Purpose: To clarify the optimal volume and timing of contrast material in multislice CT(MSCT) of the chest and cardiovascular CT angiography(CTA) for the pediatric patients.

Materials and Methods: We performed 56 contrast-enhanced chest MSCT including 16 CTA using a scanner (Aquilion, Toshiba) since Feb.2001. Contrast material was administrated at a volume of 1.0~1.5 ml/kg with delay time of 30~50 seconds on routine CT. On CTA we changed them (volume:1.0~2.0 ml/kg, delay time: 6~30 s) depend on the purpose. We recorded patient’s weight, size of the intravenous catheter, volume and delay time of the contrast material and evaluated the diagnostic sufficiency of each study. Results: Sufficient vascular enhancement was achieved in all but one (in a neonate with 27 G catheter) routine CT. No significant difference observed between 1.0 and 1.5 ml/kg. Delay time of 30 s showed higher contrast than 40~50 s. 2 CTA with 6 and 8 seconds delay time demonstrated good pulmonary arterial phase but no contrast in a study with 8s delay. All 14 CTA with 15~30 s delay time revealed sufficient contrast for great vessels. Conclusion: Our experience suggests sufficient vascular enhancement was achieved with 1.0 ml/kg and 30 s delay of contrast enhancement. On CTA, further experience may be necessary for the optimization.

GASTROINTESTINAL IMAGING 21 EVALUATION OF VASCULARITY OF PYLORIC CANAL IN INFANTS WITH INFANTILE HYPERTROPHIC PYLORIC STENOSIS Marta Hernanz-Schulman, MD, Vanderbilt University Medical Center, Nashville, TN; Stein M. Sharon, MD; Heller M. Richard, MD; Lowe H. Lisa, MD; Bethel Allison, AB Purpose: To determine whether there is increased blood flow to the pylorus in infants with IHPS, and, if present, to localize flow to muscular or mucosal layers, or both. Method: 61 consecutive infants with suspicion of pyloric stenosis were referred for sonography. 27 patients did not have pyloric stenosis and served as controls. The pylorus was evaluated with color Doppler, scale set at 4.2–4.4 cm/second. Signal was graded on a 1–3 scale, 1 ¼ no signal; 2 ¼ moderate (1–5 flow pixels); 3 ¼ extensive or continuous. Flow was confirmed with Doppler spectrum. Studies were performed on Acuson Sequoia or ATL 5000, linear transducer at 6–10 MHz frequency. IRB approval and informed consent were obtained. Result: All patients with IHPS had increased flow relative to controls. Grade 3 flow to mucosal layers was present in 97 % of patients. Muscular layer showed grade 3 flow in 74 % of patients and grade 2 in 26 %. Control patients showed grade 2 flow to muscular layer in 7 %; no flow was detected in mucosal layer. Conclusion: There is increased flow to all layers of the hypertrophied pylorus, predominantly mucosal layers. Increased flow may in turn be implicated in the evolution of IHPS.

22 COMPLICATIONS OF INFLAMMATORY BOWEL DISEASE: CT IMAGING Peter J. Shipman, MBBS, Radiology, B.C’s Children’s Hospital, Vancouver, B.C., Canada; Douglas H. Jamieson, MBChB CT evaluation of patients with Inflammatory Bowel Disease (IBD) is being increasingly requested by surgeons and physicians. Its role in detecting and assessing the complications of IBD has been significantly enhanced by the application of multidetector CT, which allows high quality multiplanar image reconstruction.This poster

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aims to display the wide spectrum of complications of IBD as seen by CT. It also illustrates the value of multiplanar imaging in better displaying these complications. Complications illustrated are (Number of images): ENTERIC: Fistulae; perianal (3), entero-enteric (4), entero-cutaneous (2), entero-vesical (2). Stricture (1) Intussusception (3) GI Hemmorhage (2) Stomal Recurrence (1). EXTRA ENTERIC: Abscess (5) Sclerosing Cholangitis (4) Genitourinary; hydronephrosis (3), calculus (1) Sacroilitis (1).

25 COMPARISON OF SUBJECTIVE EVALUATION OF 99MTC-WHITE BLOOD CELLS (WBCS) UPTAKE AND QUANTITATIVE ANALYSIS IN CHILDREN WITH INFLAMMATORY BOWEL DISEASE (IBD)

23 PLAIN FILMS IN INTUSSUSCEPTION: AN ANALYSIS OF FINDINGS

Aim: To compare subjective evaluation of bowel uptake of WBCs to quantitative analysis in children with IBD. Methods: 132 WBCs scans performed in children (mean age ¼ 13.4) had visual analysis and quantitative evaluation performed blindly. For each scan, the bowel was divided in 5 segments (sigmoid-rectum, descending, transverse, ascending colon and total abdomen). The inflammatory activity was graded visually from 0 to 6 by comparing the uptake in the bowel segment with that in the liver and iliac crest. The ratio between number of counts of each segment and total abdominal counts was than calculated. Results were analyzed using Pearson correlation test. Results: There was a positive correlation between subjective scores and quantitative parameters. The correlation coefficient for sigmoid-rectum, descending, transverse and ascending colon was 0.13, 0.55, 0.36 and 0.46 respectively. The higher frequency of patients with Ulcerative Colitis might explain the higher correlation in the sigmoid-rectum. Conclusions: It has been reported that visual analysis of disease activity has excellent sensitivity, specificity and accuracy in pediatric patients with IBD studied with WBCs. Quantitative values may offer a more standardized analysis of bowel inflammation that might be useful to assess disease intensity.

Jose A. Hernandez, MD, University of Texas Medical Branch, Galveston, TX; Leonard E. Swischuk, M.D.; Eric P. Hendrick, M.D.; Carlos A. Angel, M.D. Plain film findings in intussusception are variable. In our study of 74 patients we identified the following: (1) 50 % of cases were normal, (2) the classic triad of obstruction, mass and paucity of gas in the right lower quadrant was not seen in any of our patients, and (3) after a normal study, the next most common finding was high grade obstruction (31 %) and then low grade obstruction (23 %). A mass was seen in 25 % of cases. A mass and obstruction were seen in 7 % of cases while a mass with a normal gas pattern was seen in 16 % of cases. It is important to be familiar with all of these configurations and combinations of plain film findings in intussusception, but it is most important not to be misled by the normal abdominal film. Examples of the various radiographic findings are presented.

24 NONENHANCED LIMITED CT IN CHILDREN SUSPECTED OF HAVING APPENDICITIS: PROSPECTIVE COMPARISON OF ATTENDING AND RESIDENT INTERPRETATIONS Lisa H. Lowe, MD; Kimberly S. Draud, MD; Marta HernanzSchulman, MD, Vanderbilt University Medical Center, Nashville, TN; Martha R. Newton; Richard M. Heller, MD; Theodore Speroff, PhD; et al Purpose: The purpose of this investigation is to prospectively compare the resident and attending radiological interpretations of unenhanced limited CT (ULCT) scans obtained in children with suspected appendicitis. Materials and Methods: 75 consecutive children underwent ULCT for suspected appendicitis. ULCT scans were prospectively interpreted by resident and attending radiologists, each unaware of the others’ interpretation. The probability that findings indicated a diagnosis of appendicitis, level of certainty in the ULCT interpretation, and presence of an alternate diagnosis were analyzed. Results: 25 % of children had appendicitis. The area under the ROC curve was not statistically different for residents (0.97+0.02) and attendings (0.95+0.04). The percent agreement between residents and attendings was 91 % (k=0.73+0.095). The average level of certainty tended to be higher for attendings (93 %+15 %) than residents (89 %+12 %). The sensitivity, specificity and accuracy for residents were 63 %, 96 %, and 88 % compared to attendings at 95 %, 98 % and 97 %. Residents and attendings noted alternate diagnoses in 30 % of children without appendicitis. Conclusion: There is a high level of agreement between resident and attending radiologists in the interpretation of ULCT scans in children with suspected appendicitis. However, residents tend to be less confident in their ULCT interpretations.

Fabio Ponzo, MD, Radiology, Children’s Hospital of Philadelphia, Philadelphia, PA; Martin Charron, MD; Sunwong Jang, Ph D; Jean Louis Alberini, MD

GENITOURINARY IMAGING 26 WITHDRAWN

27 CONGENITAL GIANT MEGAURETER: A PSEUDOSEPTATED MASS Anita P. Price, MD, Department of Radiology, Winthrop University Hospital, Mineola, NY; Moneer K. Hanna, MD; Jonathan S. Luchs, MD; Steven Perlmutter, MD; Douglas S. Katz, MD The ability to correctly diagnose abnormalities of the urinary tract antenatally has become increasingly important with the dramatic rise in the number of antenatal ultrasound examinations. Prenatal findings have influenced the postnatal radiologic workup of asymptomatic urinary tract abnormalities and nonpalpable abdominal masses. Abdominal masses in the neonate are most frequently related to the urinary tract. We present six cases of giant megaureter in infants less than one year of age, with radiologic and pathologic correlation. Four cases were diagnosed within the first week of life. The redundant tubular appearance of the massively dilated ureter and its relationship to the urinary bladder on crosssectional imaging can help the radiologist differentiate a giant megaureter from a septated cystic abdominal mass. Although the differential diagnosis includes lymphangioma, multicystic dysplastic kidney, omental cyst, urachal cyst, and ovarian cyst, a giant megaureter should be considered when presented with a young infant with a large cystic abdominal mass.

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28 A COMPARISON OF DIFFERENT BACKGROUND SUBTRACTION METHODS IN THE EVALUATION OF RENAL SPLIT FUNCTION

Conclusion: The proposed technique of image manipulation can be a useful tool in a few selected cases to assess the direction of flow. Figure 1: Conventional renography: frames 57 to 76. Figure 2: Difference frames: Form frame 58–57 to frame 76–75.

Roberto Accorsi, Ph.D., Radiology, The Children’s Hospital of Philadelphia, Philadelphia, PA; Martin Charron, M.D.; Michael C. Carr, M.D.; Douglas A. Canning, M.D.

30 POST-OPERATIVE COMPLICATIONS TRANSPLANT IN CHILDREN

Purpose: To compare a new background subtraction technique to existing techniques. The method estimates background by solving the Laplace equation in the renal region of interest (ROI). The rationale is that solutions to the Laplace equation are the smoothest compatible with boundary data. Inclusion of smoothness in the calculation should provide a better estimate of background activity and, thus, of the split function. Methods: A patient with a single kidney was imaged with 151 MBq 99mTc-MAG3. ROIs were drawn on 1–2 minutes frames. The phantom kidney was drawn contralateral to the present kidney. After background subtraction, the split function was compared to other techniques and background ROI choices (perirenal, suprarenal, lateral, subrenal, and bilinear interpolation) and the theoretical 0/100 % split. Results: The Laplace method showed an error of 3 %. This is better than lateral (5 %), sub- (7.2 %) and supra- (27.5 %) renal background ROIs and slightly better than perirenal (4.1 %) and bilinear interpolation (3.5 %) methods. Conclusion: The theoretical advantages predicted for the new method resulted in a more accurate result for the split function. This success on a limited sample justifies the extension of this preliminary study to a larger number of cases for statistical validation.Figure 1: Suprarental regions of interest for background cal-culation. Figure 2: Subrenal regions of interest for background calculation. Figure 3: Lateral regions of interest for background calculation. Figure 4: Distribution of activity inside the renal region of interest as estimated from a perirenal ROI, the Laplace method and bilinear interpolation. Figure 5: Dependence of the estimated split function on errors in background estimation and real split function.

AFTER

RENAL

Ricardo Restrepo, M.D., Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada; Joao Amaral, M.D.; Allan Daneman, M.D.; Peter Chait, M.D.; Bairbre L. Connolly, M.D.; Michael Temple, M.D. The radiological appearance of some of the complications after renal transplant may be suggestive of a specific process. However this is not always the case since overlap exists. In addition, normal post-operative changes can generate confusion if not recognized.Often complementary imaging or interventional modalities are required to reach a diagnosis or therapy (biopsy, aspiration, drainage, sclerosis, stenting). Radiological findings of different complications and normal post-operative changes after renal transplant in children encountered in more than 700 transplants are discussed. Examples using various modalities are presented. We divided the complications according to the place of involvement as follows: parenchymal, vascular, collecting system and intraabdominal collections. Examples illustrated will include expected post-operative changes such as edema of the arterial and ureteric anastomoses as well as pathologic entities like lymphocele, urinoma, perinephric hematoma, renal artery stenosis, renal infarct, venous thrombosis, A-V fistula, rejection, lymphoma, nephrolithiasis, transplant cyst, anastomotic leak, vesico-ureteral reflux, hydronephrosis and the effects of a disproportionately large graft. Radiologists must be aware of the limitations of post-renal transplant imaging. A flow chart is generated to facilitate the understanding and approach taking into account the time of presentation.

31 MR IMAGING OF RENAL FUNCTION 29 USE OF DIFFERENCE IMAGES FOR THE IDENTIFICATION OF FLOW PATHS IN DYNAMIC SCINTIGRAPHY Roberto Accorsi, Ph.D., Radiology, The Children’s Hospital of Philadelphia, Philadelphia, PA; Martin Charron, M.D. Purpose: To evaluate the usefulness of color-coded difference images in emphasizing flow patterns in dynamic scintigraphy. Materials and methods: A child was injected with 10 mCi of 99 m Tc-Mercaptoacetyltriglycine to evaluate the function of a renal transplant. Lasix was given at 20 min. 128 x 128 frames were obtained for 30 min at 30 s/frame. Consecutive frames were subtracted to form a sequence of difference images (i.e. frame 58– frame 57) which were color-coded to separate points of increasing and decreasing activity. Flow paths were identified by comparing areas of increased to areas of decreased activity. The information extracted from the difference images was compared to that available from the original sequence. Result: accumulation of the agent next to the pelvis, above the bladder, was evident at the end of the study. This finding was compatible with a urinoma, a reflux into a dilated extrarenal pelvis or a bladder diverticulum. Analysis of the difference images indicated that urinoma was the most likely diagnosis. An ultrasound performed the same day revealed a collection in that area.

Damien Grattan-Smith, MBBS, Children’s Healthcare of Atlanta at Scottish Rite, Emory University School of Medicine, Atlanta, Ga; Richard A. Jones, PhD; Andrew Kirsch, MD Our poster will describe how MR imaging techniques can be combined to provide a comprehensive evaluation of renal function. Techniques illustrated will include perfusion, diffusion and BOLD imaging. Technical details, as well as limitations of each technique, will be discussed. From perfusion imaging signal intensity versus time curves can be generated. From this information renal transit times can be calculated. Any delay in renal transit is highly indicative of obstruction. By determining the volume of perfused renal parenchyma, differential renal function can be estimated. Diffusion imaging is sensitive to both cellular edema and cellular atrophy, and hence to the tissue damage typically evolving from acute or chronic hypoxia. The clinical application of diffusion weighted imaging of the kidney has been limited due to both extreme motion sensitivity and anisotropic nature of the diffusion in the kidney. BOLD-sequences can demonstrate non-invasively the level of intra-renal oxygen tension, and has been used to establish a link between the low level of oxygenation in the medulla and the active reabsorption along the medullary thick ascending limb (mTAL) of the loop of Henle. Bold imaging may be a method to identify kidneys at risk for scarring and parenchymal loss.

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NEONATAL/PERINATAL IMAGING

intensity ratios. The information was used to counsel the parents and plan postnatal management.

32 MRI IN THE ASSESSMENT OF PREGNANCY RELATED INTRAUTERINE BLEEDING: A VALUABLE ADJUNCT TO ULTRASOUND?

34 BOWEL VIABILITY ASSESSMENT BY COLOUR DOPPLER SONOGRAPHY IN NECROTIZING ENTEROCOLITIS

Geert Verswijvel, MD; Jan E. Vandevenne, MD, Dept. of Radiology, St.-Jan Ziekenhuis, ZOL, Genk, Belgium; Martijn Grieten, MD; Wilfried Gyselaers, MD; Carine Van Holsbeke, MD; Geert Gelin, MD; et al

Ricardo Faingold, MD, Department of Diagnostic Imaging, The Hospital for Sick Children and the University of Toronto, Toronto, ON, Canada; Alan Daneman, MD, FRCPC; David Manson, MD, FRCPC; George Tomlinson, PhD; Arun Mohanta; Jonathan Hellmann, MD; et al

Purpose: To investigate if MRI can be an additional tool to sonography in the diagnosis of pregnancy related intra-uterine bleeding. Methods and Materials: MRI was performed in 8 pregnant women with vaginal blood loss and equivocal ultrasound results. Following sequences were used: T2 (HASTE TR 1400 msec/TE 60 msec); nonbreathold T1 (2D FLASH, TR=110 msec / TE= 4.0 msec); and GRE T2 non-breathold images (TR= 1387 msec/TE= 26 msec), with three orthogonal image planes encompassing the entire uterine-complex including cervix and vagina (Figs. 1–8). Results: MRI provided adequate anatomical visualisation of the uterus, placental tissue and intra-uterine bleeding. The signal intensities of the bleeding collections were age-dependent. Location and extent of the bleeding was best demonstrated on the 2DFLASH images. In 6/8 cases (75 %) the MR examination provided more information on the presence, the location and/or the extent of the haematoma, as compared to the sonographic report. Conclusion: Sonography will remain the primary imaging modality in the diagnosis of pregnancy complications and routine antenatal evaluation. Nevertheless, the availability of a complementary MRI study may clear-out clinical- or sonographical doubts in the diagnosis of pregnancy related intra-uterine bleeding and provide additional data which can be important to direct the therapeutic strategy.

Purpose: To determine whether the absence of bowel wall perfusion with Colour Doppler sonography (CDS) in neonates with necrotizing enterocolitis (NEC) indicates bowel necrosis. Materials and Methods: A prospective analysis of 13 neonates with NEC (11 preterm; 2 term, 8M;5F, 24–40w GA, corrected age: 25– 46w).CDS of mural blood flow was obtained with linear transducers (8–15 MHz). Bowel wall echogenicity, wall thickness, mural air and peristalsis were evaluated. Comparison was made with radiographs and Bell’s Clinical Criteria for NEC. Results: CDS in all 7 with mild to moderate NEC (Bell stages I and II) showed increased bowel perfusion. Six did well clinically. The 7th (with moderate NEC) had one segment of bowel with absent blood flow. Laparotomy disclosed a loop of necrotic bowel corresponding to the CDS abnormality.CDS depicted multiple segments of absent bowel perfusion in all 6 patients with severe NEC (Bell Stage III). Three patients had pathologic confirmation (1 laparotomy, 2 autopsies) of bowel necrosis corresponding to the areas of absent perfusion. Of the other three, two had perforation with pneumoperitoneum and had peritoneal drains placed. Five of these 6 died. All 13 infants will be illustrated. Conclusion: CDS evaluation of the neonatal bowel appears to be a useful method for depicting bowel wall perfusion changes in NEC. Absence of perfusion is indicative of bowel necrosis.

33 USE OF FETAL MRI TO GUIDE ANTENATAL AND POSTNATAL MANAGEMENT AND INTERVENTIONS

35 GREY SCALE AND COLOUR DOPPLER SONOGRAPHY OF THE NORMAL NEONATAL BOWEL

John A. Cassese, MD, Diagnostic Imaging and Pediatrics, Brown Medical School, Providence, RI; Steven R. Carr, MD; Francois I. Luks, MD; Diana W. Bianchi, MD; Michael T. Wallach, MD

Ricardo Faingold, MD, Department of Diagnostic Imaging, The Hospital for Sick Children and the University of Toronto, Toronto, ON, Canada; Alan Daneman, MD, FRCPC; David Manson, MD, FRCPC; Paul Babyn, MD, FRCPC; George Tomlinson, PhD; Arun Mohanta; et al

Fetal MRI has become an increasingly popular problem-solving modality in difficult obstetric cases. Several recent articles have proven the value of fetal MRI in guiding management decisions and in planning interventions. The purpose of this poster is to highlight three unique cases in which the fetal MRI was essential in the decision making process. Comparisons will be made to prenatal ultrasound and various postnatal imaging in all cases. Outcome data is also available for all cases. Case 1: Twin-twin transfusion syndrome: Fetal MR images showing discordance between twins, relationship of the umbilical cord insertions and the location of the inter-twin membrane. This information was used to plan laser ablation therapy. Case 2: Cloacal anomaly in a fetus of a monochorionic, mono-amniotic twin pregnancy: Prenatal ultrasound and MR images demonstrating the anomaly and screening of the normal twin. MR image showing the amniotic fluid volume. MR images demonstrating lung volume calculations and lung:liver signal intensity ratios to assess for lung hypoplasia. Follow-up VCUG showing anomaly. Case 3: Fetus with homozygous achondroplasia: Fetal MRI used to evaluate the base of the skull for brainstem compression and degree of lung hypoplasia. Images to demonstrate the foramen magnum, lung volumes and signal

Purpose: To determine normal neonatal bowel appearances and whether bowel wall perfusion can normally be detected with Colour Doppler Sonography (CDS). Materials and Methods: Bowel was studied in 20 fasting neonates without evidence of bowel or cardiovascular disease. (12M;8F,GA:24–41w, corrected age: 31w–45w). Sonography was performed with linear transducers (8–15 MHz). The abdomen was sampled in four quadrants. Bowel wall echotexture, wall thickness, peristalsis and mural blood flow were evaluated.Colour Doppler (CD) was performed to assess mural blood flow (# of CD signalsdots and lines/cm2). Velocity was set at 0.057–0.11 m/s. CD flow was determined to be present when CD signals were reproducible or documented with pulsed waveforms.Descriptive statistics were calculated for measurements derived from CDS. Results: Bowel thickness ranged from 1–2.6 mm (mean 1.61 +/ ) 0.4). Peristalsis was a minimum of 10 contractions/min in all. Bowel wall perfusion was seen in all 20 (80 quadrants). CD signals ranged from 1–6 dots/cm2 (mean 3.25 +/) 0.46), in all quadrants. Linear CD signals were not always seen in all quadrants and

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ranged from 0–2 thin lines per cm2 (mean 0.81 +/) 0.25).CDS images and statistics will be shown. Conclusion: This study has documented that bowel wall perfusion can be detected in the normal neonate by CDS and provides baseline information to evaluate neonates with suspected bowel necrosis.

36 WITHDRAWN

37 USING SENSIVITY ENCODING (SENSE) ACCELERATION AND INNER VOLUME IMAGING (ZOOM) TECHNIQUES TO MINIMIZE RADIO-FREQUENCY EXPOSURE AND TO SHORTEN IMAGE ACQUISITION DURATION IN FETAL MR: WORKIN-PROGRESS Taylor Chung, M.D., Edward B Singleton Dept of Diagnostic Imaging, Texas Children’s Hospital, Houston, Texas; Raja Muthupillai, Ph.D.; Richard M. Braverman, M.D.; Christopher I. Cassady, M.; Dionne R. Dowdy, R.T. (R) (MR) This poster illustrates preliminary work of application of MR techniques, SENSE and Zoom, with single-shot turbo spin echo (SShTSE) to decrease radio-frequency (RF) energy deposition and acquisition duration per image in fetal MR. RF energy deposition and acquisition duration are related to echo-train length (ETL) and echo-spacing (ESP). On a clinical 1.5T MR system, the following sequences with TE ¼ 60 milliseconds (msec) were performed on a phantom and a non-gravid volunteer: (A) SShTSE (echo-train length (ETL) ¼ 128, echo spacing (ESP) ¼ 4.3 msec), (B) SShTSE with SENSE (ETL ¼ 66, ESP ¼ 4.3 msec), (C) SShTSE with Zoom (ETL ¼ 52, ESP ¼ 5.3 msec) with respiratory trigger, (D) SShTSE with SENSE plus Zoom (ETL ¼ 28, ESP ¼ 9.5 msec) with respiratory trigger. These sequences with TE ¼ 60 and 80 ms, were applied in 3 clinical cases (3rd trimester). Calculated relative reduction in energy deposition and acquisition duration per image for the 4 sequences (A, B, C, D) on the volunteer were: 1.0, 0.25, 0.09, 0.07 and 563 ms, 284 ms, 275 ms, 266 ms respectively. The clinical images were considered to be of diagnostic quality by 3 pediatric radiologists.Images of the volunteer and the clinical cases with detail descriptions of the MR techniques and scan parameters will be shown.

CARDIOVASCULAR/INTERVENTIONAL 38 FAST FLOW LINGUAL VASCULAR ANOMALIES IN THE YOUNG PATIENT: IS IMAGING DIAGNOSTIC? Pek-Lan Khong, MD, Children’s Hospital, Boston, MA; Patricia E. Burrows, MD; Harry P. Kozakewich, MD; John B. Mulliken, MD Purpose: To describe the imaging findings (MRI and angiography) of high flow vascular anomalies of the tongue, haemangioma and arteriovenous malformation (AVM), with emphasis on the discrepant imaging findings in lingual AVMs. Materials and Methods: Retrospective review of clinical records, histologic reports and imaging studies of five consecutive patients with high flow lingual vascular anomalies. Results: One patient had haemangioma (aged 1 month) and four patients had AVMs (aged 15 months, 6, 24, and 33 years). Diagnosis was made on histology in four lesions and was based on typical clinical history in one lesion. MRI and angiographic findings of the haemangioma were typical [Fig. 1], but similar findings

of focal hyperintense mass on T2-weighted images and angiographic stain were seen in three AVMs (aged 15 months, 6 and 33 years) [Figs. 2, 3]. On angiography, there was no nidus or direct arteriovenous (AV) shunting in one AVM (aged 15 months) [Fig. 2B]. The 4th AVM had typical MRI and angiographic findings. Conclusion: The imaging findings in lingual AVMs can be atypical or inconclusive and can mimic haemangiomas, especially in the young patient. Since treatment depends on accurate diagnosis, biopsy may be necessary for lesions with inconclusive imaging findings. Figures: Fig. 1: lingual haemangioma with ‘typical’ appearances. A: Sagittal T2-weighted MRI. B: Selective right lingual arteriogram. Fig. 2: lingual AVM misdiagnosed as a haemangioma. A: Sagittal T2-weighted MRI of a homogeneously hyperintense mass. B: Sagittal post-contrast MRI showing homogeneous enhancement of the mass. C: Selective lingual arteriogram showing dilated feeding arteries, early opacification of draining veins and ‘tumor blush’. Neither a true nidus nor direct AV shunting is present. Fig. 3: lingual AVMA-Axial T2-weighted MRI showing a hyperintense ‘mass’ with ill-defined margins. B: Selective lingual arteriogram (early arterial phase) showing dilated feeding arteries, direct AV shunting and dilated draining veins, in keeping with a AVM. C: Selective lingual arteriogram (later arterial phase) showing tissue stain in the tongue lesion.

39 GO WITH THE FLOW: MAGNETIC RESONANCE FLOW ANALYSIS APPLICATIONS IN CHILDREN WITH CONGENITAL HEART DISEASE Sadaf T. Bhutta, MD, Radiology, Arkansas Children’s Hospital, Little Rock, AR; S. Bruce Greenberg, MD Magnetic resonance flow analysis is a robust technique for evaluation of velocity and flow patterns in children with congenital heart disease. The technique allows for evaluation of shunts, regurgitation, stenosis, and venous flow patterns. The exhibit will illustrate both common and unusual uses of flow analysis and include pitfalls. Case material will include left to right shunts, right to left shunts, coarctation, pulmonic stenosis, pulmonary regurgitation, Glenn shunt, and Fontan shunts.

40 FREE-BREATHING CARDIOVASCULAR MR IMAGING WITH REAL-TIME NAVIGATOR RESPIRATORY SYNCHRONIZATION IN PEDIATRIC PATIENTS AND ADULTS WITH COMPLEX CONGENITAL HEART DISEASES Taylor Chung, M.D., Edward B Singleton Dept of Diagnostic Imaging, Texas Children’s Hospital, Houston, Texas; Raja Muthupillai, Ph.D.; Ricardo H. Pignatelli, M.D.; John P. Kovalchin, M.D.; Giles W. Vick III, M.D. This poster illustrates the use of real-time respiratory navigator (NAV), which has proven to be successful in adult coronary artery imaging to eliminate respiratory motion, in cardiovascular MR (CMR) of pediatric patients and adults with complex congenital heart diseases. In 2001, 28 pediatric patients (median age: 11 years; range: 3 months to 16 years) and 2 adults (23, 25 years) underwent 34 CMR studies which include 3D fast spoiled gradient recalled echo with NAV. Reasons for CMR: exercise-induced syncope (n ¼ 18); Kawasaki disease (n ¼ 3); tetralogy of Fallot (n =2); pulmonary atresia (n ¼ 2); atrial septal defect/partial anomalous pulmonary venous return (n ¼ 2); transposition, coarctation, total anomalous pulmonary venous return. Correlations made with available echocardiograms, cineangiograms, and surgical data. NAV technique provided superior delineation of proximal

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coronary arteries, proximal pulmonary arteries and veins, atrial septum, compared to other pulse sequences used. 29 of 34 cases had excellent correlation with clinical data. One false positive case of aberrant coronary artery on CMR was noted. Four cases had no other imaging or surgery.Sub-volume maximum intersity projection (MIP) images of selected CMR cases with corresponding echocardiographic and cine angiographic images will be shown. Details of NAV technique and scan parameters will be included.

utility of the MRA results.All MRA were successfully acquired and were of diagnostic quality. All 3 infants had multiple aneurysms in the arterial system torso and limbs. Coronary MRA revealed aneurysms in all infants and correlated well echocardiographic results. Serial MRA in 2 infants showed regression of aneurysms. MRA results helped to guide therapy in all cases.Maximum intensity projection (MIP) images of CE-MRA and coronary MRA from all patients will be shown together with scan parameters in detail.

41 FAST CINE MR EVALUATION OF LEFT VENTRICULAR FUNCTION IN PEDIATRIC PATIENTS USING BALANCED FAST-FIELD-ECHO (BFFE) SEQUENCE WITH SENSIVITIY ENCODING (SENSE) ACCELERATION TECHNIQUE AND INTERACTIVE REAL-TIME PLAN SCAN: WORK-IN-PROGRESS

43 EXTRACRANIAL ARTERIAL ANEURYSMS IN INFANTS AND CHILDREN: A PRACTICAL CLASSIFICATION BASED ON ETIOLOGY AND LOCATION

Taylor Chung, M.D., Edward B Singleton Dept of Diagnostic Imaging, Texas Children’s Hospital, Houston, Texas; Raja Muthupillai, Ph.D.; Giles W. Vick III, M.D.; Ricardo H. Pignatelli, M.D. This poster will illustrate feasibility of a rapid MR examination of left ventricular function in pediatric patients. On a clinical 1.5T MR scanner, we used interactive real-time plan scan tool (to obtain the short axis plane of left ventricle (LV)), and 2D cine bFFE sequence with SENSE acceleration, to achieve 33 milliseconds temporal resolution evaluation of LV function. Both breath-holding (higher spatial resolution) and free-breathing (lower spatial resolution) examinations were performed in 4 patients (ages: 9, 10, 11, 15 years) with dilated cardiomyopathy (n ¼ 2) and muscular dystrophy (n ¼ 2). Breath-hold duration per location was 4 seconds. LV was covered in 10 locations. Free-breathing scan time for the entire LV was 25 to 34 seconds (acquisition time per image ¼ 2 heart beats). LV ejection fraction (LVEF) was computed using both breath-hold and free-breath data by manually tracing LV endocardial margin on enddiastolic and end-systolic images.Total scan time of entire examination ranged from 18 to 21 minutes. All patients could comfortably perform the breath-hold sequence. LVEF from breathholding sequences and free-breathing sequences for the 4 patients respectively were: 23 % vs 27 %, 52 % vs 56 %, 63 % vs 55 %, and 28 % vs 24 %.Detail scan parameters for both breathhold and free-breathing bFFE sequence with SENSE will be shown.

42 MAGNETIC RESONANCE ANGIOGRAPHY (MRA) OF THE TORSO AND CORONARY ARTERIES IN INFANTS WITH ACUTE PRESENTATION OF KAWASAKI DISEASE Taylor Chung, M.D., Edward B Singleton Dept of Diagnostic ImagingT, Texas Children’s Hospital, Houston, Texas; Richard M. Braverman, M.D.; Giles W. Vick III, M.D.; Ricardo H. Pignetelli, M.D.; Grace C. Kung, M.D.; Maria D. Perez, M.D. This poster illustrates the utility of MRA of the torso including the coronary arteries in the clinical evaluation of infants with Kawasaki disease. Three infants (age range: 3 to 6 months) were imaged with clinical MR 1.5T scanner using time-resolved contrastenhanced MRA (CE-MRA) of the whole body with SENSE acceleration technique (n ¼ 6) and non-contrast coronary 3D-MRA with respiratory navigator technique (n ¼ 6). All patients were sedated and freely-breathing. Scan times for each CE-MRA acquisitions were 5 to 6 seconds ( average: 8 acquisitions) and approximately 6 to 8 minutes for each coronary MRA acquisition (average: 3 acquisitions). Results of coronary MRA were compared with echocardiography. Medical records were reviewed. Referring pediatric rheumatologists were consulted to determine the clinical

Ricardo Restrepo, M.D., Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada; Marilyn Ranson, M.D.; Joao Amaral, M.D.; Peter Chait, MBBCh; Bairbre L. Connolly, M.B.; Michael Temple, M.D.; et al Aneurysms in this age group are rare and important to recognize as they have associated risks of rupture, thrombosis, hypertension, limb loss and even death.The pathogenesis of aneurysms in infants and children unlike the common arteriosclerotic lesions in adults is variable.True and false/pseudoaneurysms can exist. A classification was made according to the underlying vasculopathy which included congenital, phakomatoses, connective tissue disorders as well as inflammatory, infectious, metabolic, traumatic and idiopathic causes.Examples of aneurysms were collected and a review of the radiological findings based on the above classification will be presented using a variety of modalities. Kawasaki disease, Marfan and Ehlers-Danlos syndrome, polyarteritis nodosa, tuberous sclerosis, mycotic, idiopathic, iatrogenic and post traumatic cases are presented.Recognition of aneurysms in children is important as appropriate early treatment can be instituted thereby preventing complications. Identifying the underlying vasculopathy is essential as some of these children have progressive disease. A practical classification based on etiology and location is illustrated.

EDUCATION 44 AN INTRODUCTORY WEB-BASED CURRICULUM IN PEDIATRIC RADIOLOGY: A HANDS-ON INTERACTIVE DEMONSTRATION Janet R. Reid, MD, FRCPC, Pediatric Radiology, Cleveland Clinic Children’s Hospital, Cleveland, Ohio; Marilyn J. Goske, MD; Stuart C. Morrison, MD; Sunny Chung, MD; Mariana Hewson, PhD Purpose: For the radiology resident, the ever-increasing workload and lack of curriculum mean a variable educational experience in pediatric radiology. Newer maintenance of certification mandates from the American Board of Radiology (ABR) will require that lifelong learning (LLL) begin during medical training and include interactive self assessment. We developed an introductory webbased curriculum in pediatric radiology to address these needs. Materials and Methods: A resident needs-assessment determined a core curriculum of 100 topics. Funding was obtained to develop 20 learning modules using a team of four pediatric radiologists, an educator, webmaster, artist and photographer. Results: Thirteen interactive computer-based modules have been developed. Each module includes learning objectives, pre- and posttest questions, text, illustrations and images, references and

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certification upon completion. Modules were created, internally peer-reviewed and published to a test site for evaluation. Residents evaluated the modules and validated the current format as a learning tool. Conclusion: This demonstration allows the attendee to explore this interactive curriculum on a computer. This web-based curriculum provides a standardized self-directed approach to resident teaching and fulfills the ABR challenge to develop LLL tools for resident teaching. (This project is supported by a Seed Grant from the Research and Education Foundation of the Society for Pediatric Radiology.)

GENERAL IMAGING 45 INFLAMMATORY PSEUDOTUMORS Lakshmana D. Narla, MD, Radiology, MCV Hospital, Richmond, VA; Stephanie Spottswood, MD; Beverly Newman, MD; Shireesha Narla, MD; Rajasekhar Kolli, MD Purpose: To familiarize the radiologist with the spectrums of findings and treatment plans for inflammatory pseudotumors. Material and Methods: Various examples of inflammatory pseudotumors were reviewed with respect to clinical presentation, tratment and follow up. Results: Inflammatory pseudotumors, so named because of their propensity to clinically and radiologically mimic a malignant process, consist of inflammatory cells and myofibroblastic spindle cells. Several other names have been used to describe inflammatory pseudotumors, including: plasma cell granuloma, plasmacytoma, xanthoma, xanthogranuloma, fibroxanthoma fibrous histiocytoma and solitary mast cell granuloma. This entity was first described in 1939, with the lung being the most common primary location. Since that time, inflammatory pseudotumors involving the following additional sites have been described: stomach, liver, pancreas, kidney, adrenal, retroperitoneum, bladder, thyroid, tonsil, fourth ventricle, spinal cord, meninges and central nervous system.The purpose of this exhibit is to show the appearance of inflammatory pseudotumors involving the right atrium, lung, bronchus, adrenal and iliopsoas muscle. The pathogenesis, natural history, treatment, as well as imaging findings will be described. Conclusion: As more and more cases of Inflammatory Pseudotumors are being reported, radiologists should be aware of this entity.

46 NORMAL LIVER, SPLEEN, KIDNEY MEASUREMENTS IN HEALTHY PRETERM AND TERM NEWBORNS: ASSESSMENT BY ULTRASONOGRAPY Sureyya K. Soyupak, MD, Department of Radiology, MCV Hospital, Richmond, VA; Nejat Narli, MD; Hacer Yapicioglu, MD; Mehmet Satar, MD; Erol H. Aksungur, MD This study was conducted in order to assess normal liver, spleen and kidney dimensions in premature and term newborns and determine the acceptable range. A total of 253, 99 premature and 154 mature, healthy newborns were evaluated within the first week of life by sonography. Infants were grouped according to gestational age, and those with congenital anomalies, heart failure and kidney and liver dysfunctions were excluded. Gestational age ranged from 24–41 weeks, weight ranged from 638–4800 grams. Measurements were compared with age and weight of the infants. Tables of normal ranges for kidney, liver and spleen measurements according to age and weight are obtained.

47 PERIPHERALLY INSERTED CENTRAL CATHETERS IN LOW WEIGHT INFANTS Josee Dubois, MD, Department of Medical Imaging, Universite´ de Montreal, Montreal, Quebec, Canada; Laurent Garel, MD; Francoise Rypens, MD Purpose: To assess the feasibility and complications of peripherally central inserted catheters (PICCs) in patients under 6 kg of weight. Materials and Methods: 205 patients under 6 kg of weight (median: 3.4 kg) were referred for central venous access between January 1998 and August 2000. The indications were: prolonged antibiotherapy or chemotherapy (n=51), total parenteral nutrition (n=20), venous access (n=134). Most procedures were performed under sedation, and guided by phlebography. After insertion of a guide wire through a 24G teflon catheter, and dilatation of the access, a polyuretane catheter was positioned at the superior vena cava-right atrium junction. We retrospectively reviewed the success rate, the technical data, the duration of the PICC and the complications. Results: The success rate was 95.6 % (196/205), the catheter size 18G in 168 cases and 20G in 28. The main technical features were as follows: number of punctures 1–8 (mean 2.2), fluoroscopy time 3.16 min., average duration of PICC 14 days, site of entry below elbow n=130, above elbow n=66, complications: dislodgment 9/196, lumen occlusion 14/196, superficial thrombophlebitis 8/196, infection 5/196, thrombosis 0/196. In 4 of the 9 failures, a femoral vein access was performed. Conclusion: 1. PICC placement is feasible and safe in infants. 2. A phlebographic guidance is essential. 3. Polyurethane catheters are easy to insert in small veins.

48 NATURAL COURSE OF NEUROBLASTOMA DETECTED BY MASS SCREENING: THE ROLE OF DIAGNOSTIC IMAGING Mikiko Miyasaka, M.D., Radiology, Kanagawa Children’s Medical Center, Yokohama, Kanagawa, Japan; Noriko Aida, M.D.; Maho Takeuchi, M.D.; Kazutoshi Fujita, M.D.; Aya Abe, M.D.; Yasunori Toyoda, M.D.; et al Purpose: To clarify the natural course of mass screened neuroblastoma by using diagnostic imaging. Materials and Methods: Since 1993, 26 out of 62 patients with massscreened neuroblastoma by urinary VMA/HVA levels about 6-month-old were enrolled in our observation program more than 6month periods. The observation period ranged to 88 months (mean of 33 months) with using US for the abdomen and MRI for the mediastinum. We divided the patients into three groups by the final tumor size: regressed; the final volume was less than 50 % of initial volume, unchanged; 50–150 %, and enlarged; more than 150 %. Results: Sixteen patients revealed tumor regression, 5 unchanged, and 5 enlarged. There was no difference in both initial and follow-up imaging characteristics among 3 groups. In the regressed group, 4 showed initial increased tumor size followed by regression. All 16 tumors regressed after a peak level of VMA/HVA, especially, 9 out of 16 tumors regressed after normalization of urinary VMA and HVA levels. Conclusion: Diagnostic imaging plays the key role for the observation of mass screened neuroblastoma to avoid unnecessary treatment. Although imaging characteristics cannot predict the final tumor size, observation program can be proceeded if the urinary VMA/HVA levels have declined.