18th Annual Meeting of the Japanese Neuroradiological Society* Main Theme: Extended Fields of Neuroradiology Yamagata, 17-18 February, 1989 1. High-field MR imaging of Shy-Drager syndrome K.Tsuchiya ~, K. Makita 1, E.Takenaka 1, and S.Nakajima 2. Departments of ~ Radiology and 2 Internal Medicine I, National Defense Medical College, Saitama Shy-Drager Syndrome (SDS) is a form of multiple system atrophy (MSA) with autonomic nervous failure associated with cerebellar, extrapyramidal, and pyramidal involvement. We retrospectively reviewed high-field (1.5T) MR images of seven SDS patients to evaluate the possibility of MR diagnosis of this disorder. For that purpose, MR images of patients with other forms of MSA, which included three patients with striatonigral degeneration (SND), and 13 patients with olivopontocerebellar atrophy (OPCA), were also reviewed. Atrophy of the brain stem and cerebellum was noted constantly in cases of each disorder. Hypointensity on T2-weighted images (T2WI), which is probably due to excessive accumulation of iron or other paramagnetic substance, was demonstrated frequently in the pars compacta of the substantia nigra in each disorder. On the other hand, hypointensity of the putamen on T2WI probably caused by the same mechanism, which was dominant in the posterolateral portion, was noted in most cases with SDS and SND. Less common findings on T2WI included hyperintense lesions along the lateral border of the putamen in SDS and laterality of the hypointensity of the putamen in SDS and SND. We consider these findings are noteworthy in establishing the clinical diagnosis of SDS, SND, and OPCA, and also in differentiating these disorders from others presenting similar clinical pictures. However, as these diseases have common findings, their differential diagnosis based on MR imaging may not be possible. 2. MR imaging of chronic alcoholism K. Hayakawa I, H. Kumagai 2, Y. SuzukP, N. Furusawa 3, T. Haga 2, and Y. Fujiwara 2. ~ Department of Radiology, Kyoto City Hospital, Kyoto, 2 Department of Psychiatry and 3 Department of Radiology, Wakamiya Hospital, Wakamiya Cerebral atrophy and ventricular dilatation have been wellknown cerebral lesions of patients with chronic alcoholism. The purpose of the study is to evaluate the brain lesions of chronic alcoholic (CA) patients with MR imaging in comparison with normal adult controls (NC). Patients consisted of 27 male CA and 27 male and female NC. SE 500/30 and SE 2000/80-100 axial images were made with a 0.5T superconducting MR unit. 18.5% of CA were diagnosed as normal and 81.4% as abnormal; 81.4% of NC were diagnosed as normal and 18.5% as abnormal. The abnormal findings consisted of cerebral atrophy (77.7% in CA vs 14.8% in NC), ventricular dilatation (51.8% in CA), PVH (18.5% * Pres iden t : Dr. Koichi Yamaguchi, Professor, Department of Radiology, Yamagata University School of Medicine, Nishinomac Zao-iida, Yamagata-City 990-23, Japan Special Lectures: I. Sten Cronqvist: "MRI of the spine and spinal cord disease". 2. Yung Peng Huang: "Pathogenesis of cerebral vascular malformations". in CA) and focal hyperintensity (70.3% in CA vs 11.1% in NC). In CA, multiple focal hyperintense lesions were observed in cerebral white matter (66.6%) as well as in basal ganglia (18.5%) and pons (11.1%). Only in NC older than 60 were less than five of these lesions seen, exclusively in cerebral white matter. Focal hyperintense lesions in basal ganglia and pons may represent an early stage of myelinolysis (pontine and extrapontine) or focal demyelination. The only correlation with severity of MRI abnormality observed was with the patients' age. In conclusion, MR imaging of CA revealed significantly higher incidences of cerebral atrophy and ventricular dilatation as well as multiple hyperintense lesions in pons, basal ganglia and cerebral white matter which may suggest focal demyelination. 3. MRI findings on patients complaining of migraine S. Kan ~ , T. lkeda ~, K. Tadokoro 1, T. Matsubara ~, H. Igarashi 2. Departments of ] Radiology and 2 Neurology, Kitazato University Medical School, Kanagawa 4. Superficial siderosis of the brain on high-field MRI its pathology and clinical significance T.Machida ~, S.Aoki t, Y.SasakP, H.Tanioka 2, and A.FurutaL Department of Radiology, University of Tokyo, Tokyo, and 2 Department of Radiology, Kanto-Rohsai Hospital, KantoRohsai Superficial siderosis of the central nervous system is a rare condition. The clinical and MR findings are described in 15 cases of superficial siderosis of the brain. This entity is clinically incidental, but patients can reveal cranial nerve palsies on examination, and cerebellar ataxia. It is manifested as marked low intensity around the brain surfaces on T2-weighted images (long TR, TE spin echo images). It is divided into two categories pathologically. Diffuse marginal siderosis was demonstrated in three cases on MRI, and localized marginal siderosis in 12. Intracranial hemorrhage from tumors that continue to bleed can result in diffuse marginal siderosis, and hemorrhage from AVMs and cerebral aneurysms in localized marginal siderosis. 5. Diagnostic imaging of a suprasellar meningioma Y. Tsukamoto ~, C. Sato ~, H. Nakata ~, T. Fukushima 2, A. Yokota 2, and N. MatsuokaL Departments of ~ Radiology and 2 Neurosurgery, University of Occupational and Environmental Health, Fukuoka 6. MRI findings in skull base tumors with intraand extracranial extension T. Makiuchi 1, M. Niiro t, K.Senoo 1, K.Kadota 1, T.Asakura ~, M. Atsuji 2, and H.Tokimura 2. ~ Department of Neurosurgery, Faculty of Medicine University of Kagoshima, Kagoshima City, and 2 Atsuji Neurosurgical Hospital, Kagoshima MRI findings in nine patients were reviewed. MR images were obtained by using 0.1 Tesla, 0.5 Tesla, 1.0 Tesla magnet systems. The nine tumors included two of intracranial origin and seven

The clinical benefit of iotrolan, a non-ionic dimeric contrast agent, was compared with the commonly used non-ionic contrast agent iopamidol, in a multicenter study in cerebral angiography. Iotrolan provided a diagnostic angiographic effect with a reduced rate of adverse events when compared with iopamidol. Heat sensations at the site of iotrol an injection were apparently milder than with iopamidol, and no effects on hematology, blood biochemistry or urinalysis were observed. The clinical benefit of iotrolan, assessed after consideration of imaging efficacy and overall safety, was good.

A comparative randomised open study was carried out in 120 patients uncle undergoing cerebral angiography, to compare two low-osmolar contrast media (LOCM). All the patients participated voluntarily in the trial. Half the patients (n = 60) received sodium and meglumine ioxaglate (Hexabrix 320) and the other half (n = 60) iohexol (Omnipaque 300). Contrast agent efficacy was evaluated at the different cerebral levels explored. Adverse reactions were recorded immediately and 24 h post-administration. Diagnostic quality was considered excellent in 95% of cases with Omnipaque and in 97% of cases with Hexabrix. Image quality was excellent in 95%, of cases with Omnipaque and in 100 % of cases with Hexabrix. In terms of both efficacy and safety, no significant difference was observed between the agents. Thus, low osmolality would appear to be the essential factor in this indication as far as safety is concerned. No significant difference in safety was noted between the ionic LOCM Hexabrix and the non-ionic LOCM Omnipaque.

From January to December 1990, we performed a prospective survey of adverse reactions to contrast media at two different institutes of Juntendo University. We collected a total of 4555 case sheets during the period. The radiological procedures we investigated were computed tomography, intravenous urography, arteriography, venography and myelography. Low osmolar iodine contrast medium was used almost exclusively (except for five cases). The overall incidence of adverse reactions was 7.0%, and there were no severe or fatal reactions. The incidence of adverse reactions was higher in females (8.5%) than in males (6.1%). The incidence of adverse reactions increased according to the dose of contrast medium, especially when more than 101 ml was injected. Intra-arterial injection caused adverse reactions most often, followed by regular intravenous injections, followed by bolus intravenous injections. Adverse reactions occurred most often during injection. The next occurred in 5 minutes after injection, and then, 5-10 minutes after the injection of contrast medium. The incidence of adverse reactions was higher in patients with a history of allergy or previous reactions. Allergic adverse reactions were observed at a higher frequency. Pretesting was performed in 56.7% of the cases.

The authors illustrate a new method to identify the pre- and postcentral gyri on computed tomographic (CT) and magnetic resonance (MR) images of the brain on the basis of the pattern of the medullary branches of the cerebral white matter. The most commonly used method to identify the gyri depends on recognition of the central sulcus by surface arrangement of the sulci. The two methods were compared by analysis of CT images of 104 subjects who had normal findings (age range, newborn to 60 years; 57 males and 47 females). The usefulness of the new method was also determined in angiographic studies of nine patients with space-occupying lesions. The method is especially helpful for identification of gyri on the lower level of the centrum semiovale and if space-occupying lesions are present that may result in a blurred depiction of sulci. Since MR imaging depicts the medullary branches more clearly than does CT, this new method should facilitate identification of the gyri with either modality.

From January 1989 to December 1989, we performed a prospective survey of adverse reactions to contrast media at three institutes of Juntendo University. We collected a total of 4365 case cards during the period. Low osmolar iodine contrast media were given in all but one case. Procedures using contrast media included computed tomography, intravenous urography, arteriography, venography and myelography. The overall incidence of adverse reactions was 6.6%, and there were no severe or fatal reactions. The incidence of adverse reactions was about the same in both sexes. However, in males, the incidence was higher in the fifth decade, and in females, it was higher in the third and seventh decades. There was no relation between the dose of contrast medium and adverse reactions. Intravenous bolus injections caused adverse reactions more often, followed by intra-arterial injections and then usual intravenous injections. The incidence of adverse reactions in patients with a history of allergy or previous reactions was higher. Pretesting was performed in 48.9% of the cases.

Left-to-right differences in cerebral structures of the posterior temporal and inferior parietal region were investigated in CT examinations from 500 cases, by anatomic analysis based on the medullary branches of cerebral white matter. On the left side, the planum temporale and middle temporal gyrus were positioned more posteriorly, the intraparietal sulcus was deeper and lower, and the folding of the inferior parietal lobule was more extensive. The lateralization of the planum temporale diminished gradually from 19 years of age downwards. An anatomic analysis of the medullary branches succeeded in revealing the cerebral asymmetry and is expected to be useful in magnetic resonance imaging.

Neuroradiological findings in a 44-year-old male with the typical mild type of Hunter's disease are reported. Cranial MRI revealed patchy areas of increased and decreased signals in T1- and T2-weighted images in the thalamus and the basal ganglia giving rise to a honey comb-like appearance as a whole. The deep white matter showed high signals in the T2-weighted image. To our knowledge, the honey comb-like appearance has never been reported in this disorder. Deposition of mucopolysaccharides and/or glycolipids and increase in fluid content seem to be responsible for these changes.

A watershed infarction is a specific type of a cerebral infarction. This occurs at the border zone between major cerebral arteries. Its CT findings are characteristic as a wedge shaped low density appearing either in the superior frontal region (watershed between anterior and middle and posterior cerebral artery), and always involving the deep white matter onto the ventricle wall. Even though the CT feature is small, a patient, without exception, suffers from neurologic deficit. We studied four cases of a watershed infarction on X-ray CT and compared with 123I-IMP SPECT. DSA was also made to demonstrate an obstruction of an artery which was usually found at the more proximal segment then what we expected from the CT feature. The findings on the 123I-IMP SPECT were better predictable of neurologic symptoms and they were larger in extent than the CT findings.

The authors describe 'salt and pepper on the face' pain in a case of medullary arteriovenous malformation (AVM), which was caused by post-operative hemorrhage from a very small residual nidus of AVM left remaining in the left dorsal medulla. The peculiar, sharp, jabbing pain, which has been rarely reported at the onset of intracranial hemorrhage, was followed by acute elevation of blood pressure, arrhythmia, cardiac and respiratory arrests. The patient had been in a comatose state for a month and gradually recovered from the cardiopulmonary and neurological derangements. The pathophysiology of the phenomenon which occurred in this case is discussed.

Intramedullary schwannoma without evidence of von Recklinghausen's disease is extremely rare. Only 23 cases have been reported in the literature. A 42-years-old woman with transverse type myelopathy at the level of Th 6, was referred to our department. Myelography showed diffuse swelling of the thoracic cord. Delayed myelo CT scan revealed the existence of syrinx at C 6 and Th 10 spinal cord level. On NMR spin echo image, high intensity signal with an ovoid shape was visualized in Th 7-8 spinal cord parenchyma and the syrinx was verified below the level of C 5. Based on these findings, she was diagnosed as having Th 7-8 intramedullary spinal cord tumor. Th 6 to Th 9 laminectomy followed by the complete removal of well encapsulated tumor was performed. The rostral and caudal pole of the tumor was found to be located intramedullary. The tumor at the level of Th 7-8, extended not only to the extramedullary space but also to the extradural space. Histopathological examination revealed that the specimen was Antoni A type neurinoma. She showed good recovery. Following hypotheses have been postulated on the cytogenesis of intramedullary schwannoma in the literature: Central displacement of Schwann cells during embryonic development. Schwann cells ensheathing aberrant intramedullary nerve fibers. Schwann cells along the intramedullary perivascular nerve plexus. A critical area where posterior root loose their sheath on entering the pia mater. Transformation of pial cells of neuroectodermal origin into Schwann cells. The cytogenesis of these reported cases may not be identical.(ABSTRACT TRUNCATED AT 250 WORDS)