CT-scan and intraocular tumours: detection and assessment of size and extrascleral growth of uveal melanomas.

Twenty-two patients, who were suspected of an intraocular tumour, were examined with the high resolution thin slice CT-scan (1.5 or 3 mm slices). The final diagnosis in 14 cases was an uveal melanoma, and in 3 cases in which an uveal melanoma was suspected a chorioretinal haemorrhage, an exudative macular degeneration type Junius Kuhnt and an intrascleral foreign body were respectively found. In 2 cases intraocular metastases were demonstrated, and in 2 other cases malignant lymphomata. One patient had a haemangioma. In 10 of the 14 patients with uveal melanomata enucleation was performed and 4 were treated by ruthenium application. The CT-scan was compared with ultrasonographic, operative and histological findings. From the study it appears that the CT-scan is useful for screening uveal melanomas. It is however difficult to distinguish the uveal melanoma from a secondary retinal detachment; differentiation from an exudative macular degeneration was not possible. The size of the tumour was only represented correctly on the CT-scan in half the cases. CT examination fails to demonstrate or exclude epi- and extrascleral growth. The multiple metastases and the haemangioma could only be seen with difficulty on the CT-scan; the latter was however clearly visible after the injection of contrast. The foreign body could be clearly seen without contrast.