C. Manelfe

Pure motor hemiplegia: CT study of 30 cases.

Pure motor hemiplegia (PMH) is a well defined syndrome usually caused by ischemic lesions of lacunar type located either in the internal capsule or in the pons. Angiography and isotope scanning are usually normal. CT scan reveals small deep infarcts and appears to be the most reliable investigative method. The CT scan findings are described of thirty patients with PMH of rapid onset (less than 36 hours). In 29 of the 30 cases a lesion was found which could explain the PMH. Small hemorrhages (2 cm in diameter) in the posterior limb of the internal capsule were noted in two cases. Ischemic lesions were found in 27 patients, 22 patients had a single lesion (20 capsular and 2 pontine), while 5 patients had 2 lesions (2 bi-capsular, 3 capsular and pontine). Three varieties of ischemic capsular lesions were observed. We found in 15 cases a capsulo-putamine-caudate infarct (type I); in 8 cases a capsulo-pallidal infarct (type II); and in 2 cases an anterior capsulo-caudate infarct (type III). Type I corresponded to the area of the lateral lenticulostriate branches of the middle cerebral artery. Type II involved the territory of the perforating branches of the anterior choroidal artery. We suggest that type III involves the territory of the internal lenticulostriate branches of the anterior cerebral artery. Lacunes are generally linked to arterial systemic hypertension. However, only 16 of 30 patients in this series were chronically hypertensive.

Computed tomography in olfactory neuroblastoma: one case of esthesioneuroepithelioma and four cases of esthesioneuroblastoma.

Five cases of histologically confirmed olfactory neuroblastoma (esthesioneuroblastomas) have been studied by computed tomography (CT). Both the clinical symptoms (in particular, unilateral nasal obstruction and recurring epistaxis) and radiological findings (opacity of the paranasal sinuses) are nonspecific. Computed tomography shows a contrast enhancing mass-lesion and is more useful than conventional tomography in estimating its extension and the associated bone destruction, secondary reaction of sinusitis, and tumoral calcification. In the two cases in which the tumor was associated with exophthalmos, CT demonstrated that the muscular cone acts as a barrier preventing tumoral invasion. In cases wtih intracranial involvement, it appears that the attenuation values can be useful for differentiating between invasion by contiguity (two cases) versus metastasis (one case). Computed tomography is valuable in the follow-up and during and after radiotherapy of the tumor.

Cavernous Hemangioma of the Intracranial Optic Pathways: Ct and Mri

PURPOSE The purpose of this work was to describe the CT and MR findings in three patients with cavernous hemangioma (CH) of the intracranial optic pathways. METHOD CT and MR studies of three patients with CH of the optic chiasm were reviewed. All patients underwent MRI of the chiasmal area, with coronal T2- and T1-weighted studies as well as gadolinium-enhanced coronal and sagittal T1-weighted studies. RESULTS The patients (mean age, 40 years) presented with chiasmal apoplexy (two cases) and progressive decrease of visual acuity (one case). In all cases, MRI showed regular enlargement of the optic chiasm, with extension to the optic nerve in one case and to the left optic tract in one case. The chiasmatic dimension was 2.5-3 cm in two cases and 1-1.5 cm in the other case. In all cases, MRI revealed an acute (isointense signal on T1-weighted and hypointense signal on T2-weighted sequences) or subacute (hyperintense signal on T1 - and T2-weighted sequences) hemorrhage with, adjacent to it, an area with signals of blood of different ages, highly suggestive of CH. CT showed, in chiasmatic CHs, a suprasellar mass spontaneously denser than adjacent brain parenchyma. In two cases, microcalcifications were associated. In two cases, CT and MRI revealed slight heterogeneous enhancement after contrast agent administration. In one case, no enhancement was observed. Two patients underwent surgery by frontopterional craniotomy. The optic chiasms were swollen with an intrinsic bluish mass. The cerebrospinal fluid was not xanthochromic. Microscope examination confirmed the diagnosis of CH. After 12 months, the operated patients had improved visual acuity and visual field but did not completely recover. The nonoperated patient (because of spontaneous rapid recovery of visual acuity) was followed clinically and on MRI over 18 months. CONCLUSION CH in the optic chiasm must be suspected in the presence of an acute chiasmatic syndrome. MRI is the best imaging modality, showing either an acute or a subacute chiasmatic hemorrhage or the typical pattern of CH with heterogeneous alternation of foci of blood of different ages, with a central focus of methemoglobin, a peripheral rim of hemosiderin, adjacent foci of acute or subacute hemorrhage, and slight or no enhancement after gadolinium administration.

Histiocytosis X of the petrous bone in the adult: MRI

Two cases of histiocytosis X in young adults with involvement of only the petrous bone are reported. In the first symptoms and signs consisted of a seventh nerve palsy of gradual onset over 3 years, and in the second, of pulsatile tinnitus associated with otorrhoea of clear fluid and impaired vestibular function. CT revealed large lytic lesions of the petrous bone. T1-weighted MRI before and after gadolinium confirmed the presence of a mixed tumour of the petrous bone with marked uptake of contrast medium. Spin echo images demonstrated the absence of extradural extension, and the patency of the arterial and venous network, therefore enabling differential diagnosis from extensive glomus jugulare tumours.

Evaluation of Syringomyelia with Metrizamide Computed Tomographic Myelography

Nineteen cases of cervical syringomyelia, five surgically confirmed, were examined with metrizamide computed tomographic myelography. While a collapsed cord appeared to be a very reliable finding in this series, those cases with distended cords can be studied with sequential scans (at 3 and 24 hr), allowing the distinction between syrinx and cystic intramedullary tumor by the presence or absence of delayed cyst opacification.

Transsphenoidal encephalocele associated with agenesis of corpus callosum: value of metrizamide computed cisternography.

Transsphenoidal encephaloceles are rare congenital malformations that are classified among the medial dysraphias and that are therefore associated with an agenesis of the corpus callosum. Clinically, the diagnosis is difficult, but hypertelorism and weakening eyesight should be of suggestive value. Diagnosis is basically radiological. In the past, it was founded on roentgenography, tomography of the base of the skull, pneumoencephalography, and angiography when necessary. Today, metrizamide computed cisternography using axial transverse and coronal sections, supplemented by sagittal reconstructions, allows for a complete examination of bony, meningeal, and cerebral abnormalities.

Computed Tomography in Diabetes insipidus

Thirteen patients aged 1 to 59 years hospitalized for diabetes insipidus (DI) were investigated by computed tomography (CT). Apart from one craniopharyngioma, CT revealed in 8 out of 12 cases several modifications in the hypothalamic – pituitary region. In this group, CT demonstrated a small, round, isodense mass in the chiasmatic cistern that enhanced after contrast medium injection. Coronal and sagittal reconstructions helped pinpoint the lesion in the infundibulum and pituitary stalk, and, in one case, in the supraoptic nuclei. These findings, and the noninvasiveness of CT, make this technique one of the most accurate means of radiological investigation of DI and also of determining the efficacy of therapy.

Metrizamide demonstration of the subarachnoid space surrounding the optic nerves.

Intrathecal instillation of metrizamide has provided a useful tool for the in vivo evaluation of smaller structures adjacent to or within the subarachnoid cisterns. The authors report a case in which metrizamide filled the thin subarachnoid space surrounding the optic nerve in its course through the orbit. The finding appears to be infrequent, however, since it was not observed in any instance in a review of 80 metrizamide computed tomographic cisternograms in patients with normal intracranial pressure.

MRI of intramedullary sarcoidosis: follow-up of a case.

Abstract Intramedullary lesions are infrequently the first manifestation of sarcoidosis. We present clinical and radiological follow-up of spinal cord sarcoidosis in a 68-year-old woman, mimicking an intramedullary tumour. MRI revealed an unusual area of low signal intensity on T2-weighted spin-echo images at the core of the lesion, consistent with calcification. Clinical and MRI follow-up showed progressive resolution of the intraspinal lesion, except for the calcification, with oral steroid therapy.

Imaging in neurenteric cysts of the posterior cranial fossa

Abstract Neurenteric cysts are cystic masses lined by a columnar epithelium of endodermal origin. They are rare in the central nervous system. We report two neurenteric cysts in the posterior cranial fossa and describe their neuroradiological features. The lesions were of low density on CT and more accurately delineated on MRI. They gave the same signal as cerebrospinal fluid on all sequences. There was no contrast enhancement.