Computed tomography in choroidal detachment.

Computed tomography proved valuable in localizing and differentiating serous or hemorrhagic choroidal detachment and scleral infolding. The mean attenuation values (CT numbers) in the region of fresh hemorrhagic choroidal detachment were 74 Hounsfield units (HU). The 90% confirmation limit of the mean was 55 to 84 HU. For serosanguineous choroidal detachment, the mean was 50 HU, with a 90% confirmation limit of 46 to 54 HU. For serous choroidal detachment the mean was 46 HU, with a 90% confirmation limit of 39 to 53 HU. Inflammatory choroidal detachment showed uveoscleral enhancement, which in cross section appeared as a ring (ring sign), and subchoroidal or intrauveal accumulation of fluid. Ocular hypotony produced the characteristic CT "umbrella sign."