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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. Serial CT scans were used to show progression of disease and response to treatment.

The number of normal cellular elements present in bone marrow biopsies was compared to the extent of uptake at corresponding sites on 111InCl3 bone marrow scans in 87 patients with malignant lymphoma. Of the biopsies free of tumor, 49/54 interpreted as normocellular and 16/17 hypocellular or aplastic confirmed the scan interpretation. Of the biopsies demonstrating tumor, 10/11 of those interpreted as normocellular and 14/15 hypocellular or aplastic confirmed the scan interpretation. The 111InCl3 bone marrow scan is accurate in depicting the presence or absence of normal marrow elements, but is of value in detecting tumor only when the normal elements are extensively replaced.

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. The severity of the CT scan abnormalities correlated well with clinical severity. Because muscle cone abnormality was observed characteristically in those patients with sight loss, we suggest that pressure by the extraocular muscles on the optic nerve may contribute to visual acuity loss in this disease.