Although computed tomography (CT) remains the most frequently used imaging examination in acute cerebral infarction, its sensitivity for early detection of strokes remains limited. In middle cerebral artery (MCA) strokes less than 6 hours old, loss of definition of the gray-white interface in the lateral margins of the insula ("insular ribbon") was observed. The acute and subacute CT findings in 11 retrospective and 16 prospective patients are presented. Loss of the insular ribbon was detected in 12 of the prospective cases and in all 11 retrospective cases. The insular ribbon is supplied by the insular segment of the MCA and its claustral branches. With cessation of MCA flow, the insular ribbon becomes the region most distal from the anterior and posterior cerebral collateral circulations. Consequently, the insular ribbon effectively becomes a watershed arterial zone. Loss of the insular ribbon is thus a reflection of acute edema due to infarction. Loss of the insular ribbon appears to be another frequent and reliable finding in acute MCA stroke.
8 children with cranio-vertebral abnormalities and neurological deficits are reviewed. The specific treatment is dependent on etiology, mechanisms of compression, and whether the bony abnormality can be reduced to its normal position. Irreducible ventral compression of the cervico-medullary junction was relieved by transoral removal of the odontoid-clivus complex in 3 patients. Primary posterior decompression was done in 4 children with dorsal encroachment. A reducible Cl–C2 dislocation in 1 child with juvenile rheumatoid arthritis underwent primary posterior fusion. A detailed surgical physiological approach is described.
CT scans demonstrated a localized collection of gas adjacent to a normal sacroiliac joint in 5 patients. In each case the lesion was sharply demarcated by a thin sclerotic rim. A benign bone cyst was confirmed histologically in 2 cases. The radiologist should be aware of this appearance so as to avoid invasive procedures based on a misdiagnosis of infection or neoplasm.
Four cases of optic disk drusen were accurately diagnosed with orbital computed tomography (CT). The radiologist should be aware of the characteristic CT finding of discrete calcification within an otherwise normal optic disk. This benign process is easily differentiated from lesions such as calcific neoplastic processes of the posterior globe. CT identification of optic disk drusen is essential in the evaluation of visual field defects, migraine-like headaches, and pseudopapilledema.
Cerebellar hemangioblastomas were seen in seven persons, five being members of the same family. All were studied with constrast enhanced CT scans and vertebral angiograms. The CT scans were superior for demonstrating the cystic component of the tumors and associated hydrocephalus, features not usually evident on the angiograms. The angiograms were superior for revealing the vascular nature, supply and drainage of the tumors. In several patients the angiograms revealed more tumors than could be seen by CT. Both CT and angiography contribute important information in the diagnosis of these neoplasms.
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