[Pure akinesia with apraxia of lid-opening (author's transl)].
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Aged↗
Biomedical subjects
S Tokiguchi
Publications and source records attributed to S Tokiguchi.
Arachnoid granulations of the posterior fossa: CT and MR findings.
The radiological appearance of typically located arachnoid granulations on craniograms is well known. Arachnoid granulations of unusual size and location should be distinguished from pathological processes. We analyzed six patients with arachnoid granulations in the posterior fossa. Characteristic findings of arachnoid granulations were disclosed by computed tomography (CT) and magnetic resonance (MR) imaging; a punched out-like bone defect from the inner table into the outer table on CT scans and intensity similar to that of the cerebrospinal fluid in all pulse sequences on MR images.
Aged↗
Small cortical infarcts mimicking metastatic tumors.
Small cortical enhancing lesions mimicking metastases were demonstrated on contrast imaging in three patients without specific neurologic deficits corresponding to the lesions. One patient had a long carcinoma. However, all had cardiac arrhythmias known as major sources of cerebral emboli. Two had early cerebral infarcts and ischemic heart diseases. The lesions disappeared spontaneously on follow-up studies. They were subsequently presumed to be small infarcts. Clinical information and follow-up examinations are important to differentiate these small cortical lesions from metastases.
Aged↗
CT and MR findings of neuroacanthocytosis.
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Acanthocytes↗
"Pseudoocclusion" of the internal carotid artery: a pitfall on intracranial MRA.
We report a case showing "pseudoocclusion" of the internal carotid artery as a pitfall on intracranial MRA. Pseudoocclusion was attributed to magnetic susceptibility artifacts with metallic substances located proximal to a slab. The same finding could be reproduced on experimental MRA with a small steel coil applied on the anterior neck of a volunteer at the level of the carotid bifurcation.
Adult↗
Decreased signal intensity of the middle cerebellar peduncle on diffusion-weighted MRI in patients with large supratentorial lesions.
PURPOSE: The purpose of this work was to evaluate signal intensity change of the middle cerebellar peduncles on diffusion-weighted imaging in patients with large supratentorial lesions. METHODS: Signal intensity of the middle cerebellar peduncles was measured using a region of interest in 40 normal control subjects and in 28 patients with moyamoya disease on axial diffusion-weighted imaging with the motion-probing gradient perpendicular to the image. An additional six patients without moyamoya but with large supratentorial sequelae of hemorrhage or infarction were also included. RESULTS: There was no difference in signal intensity between both middle cerebellar peduncles in normal subjects, but lower signal intensity was consistently observed in the contralateral middle cerebellar peduncle in 12 moyamoya patients with large supratentorial lesions in the middle cerebral artery distribution. This finding was observed in the six non-moyamoya patients, too. CONCLUSION: Decreased signal intensity of the contralateral middle cerebellar peduncle might be a remote effect caused by a large supratentorial lesion in a crossed cerebellar fashion.
Adolescent↗
Focal T2 hyperintensity in the dorsal brain stem in patients with vestibular schwannoma.
BACKGROUND AND PURPOSE: The vestibular nucleus cannot be visualized on MR imaging, but some patients with vestibular schwannoma show a tiny area of hyperintensity in the dorsal brain stem on T2-weighted images. The aim of this study was to determine whether this tiny area is characteristic of vestibular schwannoma. METHODS: We retrospectively reviewed the postoperative MR images of 53 patients with cerebellopontine angle tumor. MR images were obtained with a 1.5T scanner. Spin-echo pre- and postcontrast 3-mm-thick T1-weighted axial images, 3-mm-thick fast spin-echo (FSE) T2-weighted axial images, and 0.8-mm-thick constructive interference in steady state (CISS) axial images were acquired. Surgical and histopathologic diagnosis was vestibular schwannoma (41/53 = 77%), meningioma (7/53 = 13%), epidermoid cyst (3/53 = 6%), glioma with exophytic growth (1/53 = 2%), and chordoma (1/53 = 2%). RESULTS: A tiny area of hyperintensity was observed at the lateral angle of the fourth ventricle floor in 6 patients (3 men, 3 women; age range, 24-54 years; mean age, 43 years) with vestibular schwannoma larger than 2 cm in maximal diameter on both FSE T2-weighted and CISS images. Preoperative MR images with the same pulse sequences showed the same area of hyperintensity in all these patients. CONCLUSION: Because the location of the area of hyperintensity is coincident with the vestibular nucleus, the hyperintensity may represent degeneration of the nucleus. This hyperintensity should not be confused with a postoperative lesion or a small infarction. If such hyperintensity is seen in a patient with a large cerebellopontine angle tumor, a diagnosis of vestibular schwannoma is suggested.
Adolescent↗
Primary central nervous system lymphoma presenting as diffuse cerebral infiltration.
We report a case of primary central nervous system lymphoma presenting as diffuse cerebral infiltration. On T2-weighted spin echo MR imaging using a 1.0 Tesla unit, high signal intensity lesions were presented mainly in the bilateral pyramidal tracts and also diffusely extended to white matter with brain swelling. No enhancing lesion was demonstrated after the intravenous injection of Gadolinium-DTPA, during the course of her disease. Radiological diagnosis of gliomatosis cerebri was made because of the characteristic MR appearance. Stereotactic biopsy was performed, and diffusely scattered lymphocytes, probably neoplastic, in the cerebral white matter were demonstrated histopathologically. Oral corticosteroids, radiation therapy, and chemotherapy were applied soon after her admission. The patient's condition improved dramatically. MR imaging using a 1.5 Tesla unit after the treatments showed marked regression and reduction of high intensity lesions on T2-weighted images and improvement of brain swelling. It should be emphasized that brain biopsy is important method for correct diagnosis in case of diffuse non-enhancing brain lesions like our case.
Biopsy↗