Magnetic resonance imaging in choroidal osteoma.

Abstract

High resolution magnetic resonance imaging (MRI) with surface coil and contrast material was used to demonstrate the presence of bone in choroidal osteoma. Contrary to initial impressions, choroidal osteoma does not show typical negative image of the bone in MRI scans. The ossifying tumor of the choroid appears as a bright (hyperintense) signal on T1-weighted images and as an area of relative low intensity on T2-weighted images. On contrast T1-weighted scans, the tumor showed gadolinium-DPTA (Gd-DPTA) enhancement. These MRI findings are discussed in relation with histopathologic features of choroidal osteoma and the presence of fat marrow in the intertrabecular spaces of the bone at the level of the choroid.