Computed Tomography in Graves' Ophthalmopathy

TLDR

Computed tomography with a 160 × 160 matrix provides detailed visualization of both normal and abnormal orbital anatomy in Graves’ ophthalmopathy. CT demonstrates extraocular muscle enlargement—particularly of the medial and lateral rectus and the muscle‑cone apex—correlating with clinical severity and suggesting that muscle‑cone compression of the optic nerve contributes to visual loss.

Abstract

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.