Eur. Radiol. 7, 1139–1141 (1997)  Springer-Verlag 1997

Letters to the editor References

Central pontine myelinolysis: CT technique I read with interest the very informative article about the clinical presentation and radiologic findings of central pontine myelinolysis (CPM) by Laubenberger et al. [1] in the recent issue of European Radiology. Regarding imaging they state that ‘MRI is the decisive diagnostic tool for CPM’. Standard CT scans which were performed prior to MRI in seven patients were found not to be sensitive in detecting CPM (true positive in three, false negative in four patients). This was said to be partly due to beam-hardening artefacts in the posterior fossa. To reduce beam-hardening artefacts we recommend a specific CT technique if there is suspicion of pontine or cerebellar lesions. This ‘cerebellar technique’ [2] involves 3–4 mm scanning with 20– 25° angulation of the gantry against the orbito-meatal line, which is used as a reference line for standard CT of the brain (Fig. 1 a). By this technique the beam-hardening artefacts in the posterior fossa, especially those caused by the petrous bone, can be clearly reduced. We found the technique very helpful when scanning four patients with CPM last year; diagnosis in two of them would not have been possible by standard CT scanning along the orbito-meatal line (Fig. 1 b, c). Although MRI provides better contrast than CT in imaging the pons, CT is a method that is generally available and can detect CPM in most cases if an appropriate technique is used.

Fig. 1. a Scout view demonstrating CT scans parallel to the orbitomeatal line (dotted lines) and in the ‘cerebellar technique’ angulated 22° against the orbito-meatal line (white lines). Positions of image b (black arrows) and image c (white arrows) are marked. b In this 40-year-old, long-standing alcoholic patient CT in the standard technique fails to demonstrate a pontine abnormality because of beam-hardening artefacts (arrowhead). c Scanning using the ‘cerebellar technique’ (same position of CT scan through pons as b) clearly shows a central pontine hypodense lesion (arrowhead) corresponding to central pontine myelinolysis. Beam-hardening artefacts are clearly reduced

a

b

1. Laubenberger J, Schneider B, Ansorge O, Go¨tz F, Ha¨ussinger D, Volk B, Langer M (1996) Central pontine myelinolysis: clinical presentation and radiologic findings. Eur Radiol 6: 177–183 2. Steinhoff H, Ambrose J (1981) Computertomographie des Gehirns. In: Diethelm L, Heuck F, Olsson O, Strnad F, Vieten H, Zuppinger A (eds) Encyclopedia of medical radiology. Springer, Berlin Heidelberg New York, p 279 R. J. Scheck Institut fu¨r Radiologische Diagnostik Klinikum Innenstadt Ludwig-Maximilians-Universita¨t Mu¨nchen Ziemssenstrasse 1 D-80366 Munich Germany

Reply In his letter Dr. Scheck proposes a ‘cerebellar technique’ in CT to avoid beam-hardening artefacts, using a 20–25° angulation of the CT gantry. This was discussed in several original articles [1–3] some years ago. However, data on central pontine myelinolysis (CPM) comparing CT with an optimum angulation and MRI are not available. The examinations on which our study is based were done using a standard CT technique. In fact in our patient group beamhardening artefacts caused a degradation of image quality in only one of the four patients in whom CT was negative for CPM. In the three other cases the diagnosis of CPM was not possible even in retrospective evaluation. We think that the main problem remains the lower soft tissue contrast resolution in CT compared with MRI – a fact which has been documented in numerous publications. Especially in early CPM the changes are often very subtle: we doubt that CT will show them as reliably as does T2-weighted imaging. However, if MRI is not available then CT should be performed with the optimized gantry angulation to avoid artefacts in the posterior fossa if CPM is clinically considered probable.

c

1140 References 1. Mostro¨m U, Ytterbergh C (1986) Artifacts in computed tomography in the posterior fossa: a comparative phantom study. J Comput Assist Tomogr 10: 560–566 2. Rozeik C, Kotterer O, Preiss J, Schulz M, Dingler W, Deininger C (1991) Cranial CT artifacts and gantry angulation. J Comput Assist Tomogr 15: 381–386

Book reviews Coel, M., Leung, J.: Atlas of Nuclear Medicine. Philadelphia: W. B. Saunders 1996. 722 pp., (ISBN 0-7216-3578-4), Hardcover, £ 172.00. This is an atlas based on the extensive personal experience of the authors. The format is handy, not too heavy to be used as easy reference and quick check on unusual presentations of disease. The atlas is based on the “gamut approach,” i. e., diseases are firstly categorized according to location and secondly to etiology. In the foreword and preface, it is mentioned several times that this atlas should be used in conjunction with a standard textbook. The images are of prime importance, and the text is kept to a minimum. There are cross references to chapters, and disease presentations may be listed more than once. A minor shortcoming is the method of referencing: chapter numbers are used, omitting the page number, which would have been more convenient. The atlas presents cases with classic and contemporary radiopharmaceuticals, and provides a comprehensive survey of the diagnostic field. There are 17 sections: bone, liver, spleen, hepatobiliary system, GI tract, salivary glands, renal, testes, lungs, heart, vascular system, brain, thyroid, endocrine, and breast. In addition, there are the sections/chapters on infection and tumor imaging, which do not follow the gamut approach. Each chapter is well organized and presents illustrative case reports, supplied with notes and cross references. In addition, flow charts and tables with differential diagnoses are given. These contain valuable information and will enhance diagnostic patient management. Color images are presented for the heart and brain; the other images are all black-and-white glossy prints. A novel concept in this atlas concerns the aim of the authors, one a practitioner with long experience and the other a trainee in radiology. On the one hand, this atlas is meant to be a quick reference, and on the other, a visual teaching file. The authors have emphasized that both classic and variant expression of disease are important, and they have succeeded in collecting an impressive databank of abnormal patient cases. In my own experience, the most difficult topic to teach is, however, variants of normal. Residents are quite able to detect small or subtle differences, but explaining why certain changes are “variations of normal” and others abnormal is the real challenge. In this respect, welcome surprises with normal variants are provided for the hepatobiliary, renal, lung, vascular, and thyroid system. The variants, however, indicated normal presentations with different radiotracers, changes in the acquisition protocol, or pharmacological interactions. Otherwise, this atlas shows one normal case per chapter, which does not serve the purpose of demonstrating variations of normal patterns. A few layout errors were found in the index. A particular strength of this atlas is the amount of tables with differential diagnoses and algorithms for clinical workup. Notes are incorporated that function as “teaching” or “decision” points.

Book reviews 3. Yeoman LJ, Howarth L, Britten A, Cotterill A, Adam EJ (1992) Gantry angulation in brain CT: dosage implications, effect on posterior fossa artifacts, and current international practice. Radiology 184: 113–116 J. Laubenberger Department of Diagnostic Radiology University of Freiburg Hugstetter Strasse 55 D-79106 Freiburg Germany

European Radiology The first section is bone, with 11 chapters, a truly remarkable set of patients and diseases, and is well done. I particularly liked the soft tissue chapter, since it was not aimed at artifacts or pitfalls, but listed the entities and their variants. It was amazing to read that stage I of RSDS in Hawaii has decreased flow. This is contrary to well-established textbooks and the official Society of Nuclear Medicine syllabus. Apparently, it remains a complex and fascinating syndrome. The second section on liver is a classic and informative overview, which starts off with the colloid scan. A typographic error is found in chapter 13, in which the tongue-shape portion of the right liver is called a Reidel’s lobe, misidentifying the famous physician Riedel. The third section is a short listing of essential spleen disorders. In the fourth section on hepatobiliary scintigraphy, the authors labeled the images as HIDA scans, which is incorrect since HIDA is an obsolete radiopharmaceutical (they used mebrofenin). Normal variants in chapter 21 refer to pharmacological interactions and are concisely reported. Section five deals with the GI system and is short, especially on gastric emptying. An extra chapter (33) is attributed to bowel infections (Sect. 15 deals with infection in general). In Sect. 6 the main topics of salivary scintigraphy are shown. Section 7 presents the renal system and is a real classic. Beautiful images are given for DTPA and Hippuran scans. MAG3 is mainly used for children and transplants in the authors’ hospital. Pharmacological interactions with captopril are present as is diuretic renography. Overall, this section appears to be somewhat dated, thereby providing a solid basis to study clinical renal scintigraphy. Handy tables are given for the differential of small kidney, infection, urinary obstruction, bilateral enlargement, and renal defects. In the evaluation of renal transplants, I missed ATN as a frequently occurring complication. The testes are the subject of Sect. 8 and deserved 5 pages. Lung perfusion and ventilation are presented in Sect. 9, and organized to matched vs mismatched vs reversed mismatched, and solitary vs multiple defects. In addition, chapters are devoted to lung infections and tumors. In Sect. 10 colorful images of the heart are given. Both planar and tomographic studies are shown. The tomograms are small and a zoomed image would be preferential, especially next to the planar images (a suggestion for the following edition?). The text is amply enriched with tables, triage schemes for CAD, and quantitative analysis. The ventriculography section is tomographic (gated SPECT) and concise. The cardiac section is completed with shunt evaluation and inflammatory disease. The vascular system in Sect. 11 comprises venous, arterial, and lymphatic diseases. It is a superb demonstration of the possibilities of radionuclide angiography with fast, easily performed, non-invasive flow studies. Section 12 is the most colorful by showing surface rendered images of brain perfusion. In general, the brain tomograms are heavily filtered, and a color scale would have been

Book reviews handy to assess regional perfusion differences. A chapter is devoted to brain death, very important and extremely relevant because of legal issues. The section is completed with CSF imaging. Section 13 on thyroid disease is excellent. The chapters on thyroid cancer are up to date and the issue of stunning by using high diagnostic I-131 doses is addressed. Comparison of iodine with different tracers, such as thallium and sestamibi, is discussed. The endocrine section (Sect. 14) is short and presents parathyroid and adrenal diseases. In Sect. 15 and 16 infection and tumor imaging are described. Section 15 starts with a short listing of the best indications for WBC and Ga imaging, false positives and false negatives. The gamut approach is not followed here, and a very interesting collection of infectious diseases is presented. Studies were performed with the tracers In-111 WBC and gallium. WBCs labeled with Tc-99m or monoclonal antibodies are not discussed. Tumor imaging is remarkable by its comprehensive overview of the currently available tracers. The selected cases are to the point and the text up to date. Perhaps MIBG may be incorporated next time. An illustrative number of cases is devoted to the MEN syndromes. An interesting set of studies is shown in Fig. 72-16 (patient 3) and Fig. 72-17 (patient 2), where the authors state that the octreotide was labeled with Tc-99m. The final section is on breast diseases, has flow charts for the work up of both palpable and non-palpable breast masses, and presents the presently en vogue sestamibi scintigraphy. Positron emission tomography (PET) has also been incorporated in the sections on brain and tumor imaging. Except for two tumor cases, all PET scans were from UCLA School of Medicine. Unfortunately, these sophisticated images deserve a little more respect in the final printing process. The FDG scans of the brain are printed with an unusual look-up table, and the whole-body images suffer from an erroneously set lower window. A chapter written by an expert would have prevented this. Overall, this is a comprehensive atlas comprised of many years of dedicated work. Several chapters are among the best I have seen, such as the treatise on soft tissue uptake in bone scintigraphy, vascular system, thyroid, and tumor imaging. The editors have done a wonderful job in putting together this vast amount of material. Omissions as mentioned above can be readily overcome when the second edition is published. This endeavor must have been a major challenge, since it was essentially undertaken by one practitioner. Therefore, not all chapters can be truly state of the art, as demonstrated by the images produced with older equipment. I would hesitate to recommend this atlas as a visual teaching file, and only want my residents to use it with personal supervision and guidance. A group of expert contributors would circumvent some of the shortcomings. The atlas is ideally suited for the experienced practitioner as a quick reference and as a collection of variations in disease patterns. Dr. Coel should be commended for his effort to share his enormous patient file with us and spending the years to assemble it and get it printed. The atlas is definitely not overpriced. C. Schiepers, Sylmar

1141 Grenier, P. (ed.): Imagerie Thoracique de l’Adulte, 2nd edn. Paris: Me´decine-Sciences Flammarion 1996, 767 pp., (ISBN 2-257-12491X), BEF 6197.00. One of nine textbooks of a French series, the second edition of ‘Adult thoracic imaging’ contains contributions from an impressive number of distinguished French-speaking radiologists and specialists. Thanks to the coordinating guidance of Prof. Grenier, the reader will find a well-structured, homogeneous and balanced text rather than a collection of individual contributions. The first part (10 chapters) is dedicated to imaging techniques and radioanatomy. Conventional and digital radiography as well as computed tomography (CT) are presented in detail with recent modifications and many important normal findings. The principles, advantages and limitations of high-resolution CT (HRCT), volumetric scanning (helical, spiral CT) and electron beam CT are discussed. The reader will also find concise chapters on pulmonary scintigraphy, angiography, bronchography, ultrasound and magnetic resonance imaging. Positron emission tomography (PET) and interventional applications of imaging in the chest for biopsy, drainage and therapeutic embolization are adequately represented, while conventional tomography has been omitted in view of current developments. The second part of the book systematically introduces the radiographic and CT signs of disease in all anatomic compartments with a special chapter on how to detect ventilatory disturbances. Written by Philippe Grenier, the description of the CT signs of pulmonary disease is an outstanding summary of all the diagnostic elements shown by HRCT that have enabled a much more sensitive and specific analysis of air-space disease, interstitial thickening, nodular opacities, cysts, cavities, distortion, vascular and airway disorders. The key sign of a ground glass opacity, its differential diagnosis and meaning are covered separately. The 13 chapters of the third part contain a systematic description of pathologic entities. Infection and neoplasms, according to their prime clinical role, are discussed in detail. Other chapters cover chronic airway disease, vascular problems such as pulmonary embolism, hypertension or edema, adult respiratory distress syndrome, disorders due to inhalation and the important group of diseases of unknown origin. Sarcoidosis, idiopathic pulmonary fibrosis, bronchiolitis obliterans with organizing pneumonia, collagen vascular diseases and several entities with vasculitis and alveolar hemorrhage are presented in clear language understandable to the non-specialist. Congenital, traumatic and iatrogenic lesions are appropriately covered, as well as extrapulmonary disorders of the pleura, the mediastinum, the chest wall and the diaphragm. The reader will enjoy both reading the text and studying the high-quality figures with their clear legends. Many lists of etiologies and differential diagnoses of specific signs are summarized in tables that will help the reader to find the correct diagnosis or at least a short list of possible causes. Looking at these tables offers a fast approach to many problems in daily imaging practice. Although a one-volume textbook ‘Imagerie Thoracique de l’Adulte’ can in many ways be compared with the classic multi-volume textbook by Fraser and Pare´. However, it also includes the development of imaging during the last decade, and above all the new contribution offered by HRCT. I recommend this textbook to any radiologist interested in thoracic imaging, and I would welcome an English translation. P. Vock, Berne