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Biomedical subjects

S W Atlas

Publications and source records attributed to S W Atlas.

97 records · Page 6Linked to original sources
PubMedDate not supplied

MR imaging of Tolosa-Hunt syndrome.

The Tolosa-Hunt syndrome consists of painful ophthalmoplegia caused by cavernous sinus inflammation, which is responsive to steroid therapy. The MR features of 11 patients with the clinical diagnosis of Tolosa-Hunt syndrome were studied. Two patients had normal MR studies of the orbit and cavernous sinuses. In nine patients, abnormal signal and/or mass lesions were seen in the cavernous sinuses; in eight cases, the abnormality was hypointense relative to fat and isointense with muscle on short TR/TE images and isointense with fat on long TR/TE scans. Extension into the orbital apex was seen in eight cases. In six of nine cases the affected cavernous sinus was enlarged; in five of nine it had a convex outer margin. One patient had a thrombosed cavernous sinus and superior ophthalmic vein in addition to a cavernous sinus soft-tissue mass. The signal intensity of Tolosa-Hunt syndrome in this limited series was similar to that of orbital pseudotumor and is confined to a limited differential diagnosis, which includes meningioma, lymphoma, and sarcoidosis.

Adolescent↗
PubMedDate not supplied

Internuclear ophthalmoplegia: MR-anatomic correlation.

Internuclear ophthalmoplegia is a gaze disorder characterized by impaired adduction on the side of a lesion involving the medial longitudinal fasciculus with dissociated nystagmus of the abducting eye. Eleven patients with internuclear ophthalmoplegia (nine with clinical multiple sclerosis, two with clinical infarction) underwent MR imaging with spin-echo techniques on a 1.5-T system. Nine patients also had CT. MR showed focal or nodular areas of high signal intensity on T2-weighted images in the region of the medial longitudinal fasciculus in 10 of 11 patients. In one of four patients with internuclear ophthalmoplegia who had MR after intravenous gadolinium-DTPA, an enhancing ring lesion was seen in the region of the medial longitudinal fasciculus on short TR/TE images, indicating active blood-brain-barrier disruption, which correlated with this patient's recent-onset internuclear ophthalmoplegia. CT failed to show the lesions in all nine patients examined. This report demonstrates the superiority of MR in evaluating gaze disorders attributable to brainstem dysfunction, such as internuclear ophthalmoplegia, and correlates MR findings with the relevant neuroanatomy of the medial longitudinal fasciculus.

Adolescent↗
PubMedDate not supplied

Subcortical hemorrhage: marker for radiographically occult cerebral vein thrombosis on CT.

OBJECTIVE: Cerebral vein thrombosis (CVT) is a potentially life-threatening entity with a protean clinical presentation that can lead to delays in diagnosis and treatment. Computed tomography of the brain is often the initial imaging tool in evaluation of these patients, but is frequently nondiagnostic. This study identifies subcortical hemorrhage (SCH) as an indicator of radiographically occult CVT on CT. MATERIALS AND METHODS: A retrospective analysis of all subjects (n = 24) with CVT proven by MRI over a 4 year period was performed. The CT examinations of all subjects were evaluated for the presence of SCH and signs of CVT. An evaluation of the correlation between findings on CT and MRI as well as the delay in diagnosis and treatment secondary to unrecognized CVT on CT was also performed. RESULTS: Subcortical hemorrhage was noted in 9 of 24 (38%) subjects with CVT by MRI. The CT antedated MRI in eight of these subjects as the initial evaluation for presenting neurological symptoms. Subcortical hemorrhage was noted in six of eight of these subjects as the sole CT finding. Subcortical hemorrhage as well as CVT was seen in one subject, and no abnormality was seen in the final subject. Cerebral vein thrombosis was not suggested as a diagnosis in any of the six subjects with SCH as the sole radiographic finding. In all six of these cases, a delay in diagnosis occurred pending MRI obtained subsequently secondary to clinical deterioration. CONCLUSION: Subcortical hemorrhage can be seen in association with acute CVT and can be the sole abnormality on head CT. SCH as an isolated finding on CT suggests the possibility of unrecognized CVT, warranting further investigation by MRI.

Adult↗
PubMedDate not supplied

Magnetization transfer effects in MR imaging of in vivo intracranial hemorrhage.

PURPOSE: Recent papers have hypothesized that diamagnetic effects of clotting and conformational changes in aging red blood cells immobilize the hemoglobin protein and thus are responsible for the marked hypointensity of acute hematomas on T2-weighted spin-echo MR images. To test that hypothesis, the authors evaluated 24 hemorrhagic components of intracranial hemorrhagic lesions using accepted criteria based on spin-echo images as the definitions of the stage of the hemorrhage. METHODS: As a measure of the effects of macromolecular (hemoglobin protein) immobility, magnetization transfer contrast was elicited using a pulsed saturation magnetization transfer experiment. The apparent magnetization transfer contrast (AMTC) was determined by comparing the signal intensities of saturated with unsaturated images and quantified for acute isolated hemorrhages, acute nonisolated hemorrhagic lesions, and subacute-to-chronic hemorrhages. RESULTS: The AMTC of isolated acute hemorrhage was significantly less than that of normal, white matter and gray matter, indicating the lack of significant magnetization transfer and therefore the lack of effects of restriction of hemoglobin mobility on the signal intensity of acute hemorrhage. Acutely hemorrhagic tissue (nonisolated acute hemorrhage) has significantly more AMTC than isolated acute hemorrhage, but still not exceeding that of brain parenchyma. CONCLUSION: This in vivo data concurs with in vitro data and reinforces the concept that the marked hypointensity of acute hematomas is mainly a magnetic susceptibility effect.

Adult↗
PubMedDate not supplied

Herpes zoster ophthalmicus with orbital pseudotumor syndrome complicated by optic nerve infarction and cerebral granulomatous angiitis: MR-pathologic correlation.

The authors describe a 41-year-old woman with herpes zoster ophthalmicus and extensive intracranial and orbital involvement as documented by MR and pathologically. MR showed all of the lesions that led to the ophthalmoplegia and pseudotumor syndrome, the periaxial infarct of the distal optic nerve, pontine infarcts, and granulomatous angiitis of the meningeal vessels. MR is useful in both detection and monitoring of the disease.

Adult↗