Computed tomography in orbital pseudothumor (idiopathic orbital inflammation).

CT scans of 9 patients with orbital pseudotumor (bilateral in 6 and unilateral in 3) showed findings distinct from those observed in Graves' ophthalmopathy. In bilateral involvement, they ranged from localized mass lesions to complete obiliteration of normal orbital CT anatomical landmarks; diffuse or multifocal lesions involving the posterior globe and muscle insertions were most typical of the diagnosis. However, findings in unilateral psedotumor may be indistinguishable from orbital mass lesions other than Graves' ophthalmopathy.

Computed tomography of granulomatous basal arachnoiditis.

Clinical findings are often insufficient to diagnose basal arachnoiditis and conventional neuroradiological techniques often fail to demonstrate the inflammatory process. Computed tomographic (CT) scans, however, usually can demonstrate the circle of Willis, and the basilar, sylvian quadrigeminal, and vermian cisterns. Cisternal anatomy can also be delineated on the CT scans by metrizamide cisternography.

Computed tomography in Graves' ophthalmopathy.

The CT scan with the 160 x 160 matrix demonstrated both the normal orbital anatomy and the abnormal orbital anatomy of Graves' ophthalmopathy in great detail. In Graves' ophthalmopathy, the cardinal pathologic feature of extraocular muscle enlargement was accurately reflected on the CT scan and was a distinctive, diagnostically reliable finding. Enlargement of the medial and lateral rectus muscles and of the apex of the muscle cone were the most consistent findings.

"Watershed" infarction in sickle cell disease.

A classical "watershed" infarction pattern on brain scintigraphy was demonstrated in a seven-year-old black girl with sickle cell disease. Computed tomography (CT) showed minimal abnormalities compared to the characteristic findings on the radionuclide image.