Computed tomography of orbital lesions. A radiological study of 144 cases.

During the first two years with the 160 x 160 matrix EMI scanner 144 consecutive patients referred with suspicion of orbital disease were subjected to 190 computed tomography (CT) examinations. The X-ray attenuation and enhancement patterns of the various lesions were analyzed. In general it was difficult to correlate these parameters with the histopathological features. Hemangiomas, however, showed little enhancement and meningiomas a large degree of enhancement, while malignancies, lymphomas and pseudotumors were mainly intermediate. With orbital Graves' disease a low preinjection attenuation and a large enhancement (with normal striated neck muscle as a reference) was found in the external eye muscles. The diagnostic accuracy of CT (n=143) was compared to that of A/scan ultrasonography (US, n=80) and carotid angiography (n=40). CT showed the highest accuracy of the three methods, but CT differed only statistically from carotid angiography.