Vertebral hemangiomas: MR imaging.

Vertebral hemangiomas, unlike most bone lesions, show increased signal on T1- and T2-weighted magnetic resonance (MR) images. To define the basis for these signal characteristics, a retrospective review was done of the MR imaging findings in ten vertebral hemangiomas (eight patients), and these were correlated with the findings from plain radiographic, computed tomographic (CT), and histopathologic studies. MR images showed mottled increased signal in T1- and T2-weighted images from the osseous portions of the tumors. In three patients, the extraosseous components failed to show increased signal on T1-weighted images. Chemical shift images and histologic studies demonstrated that adipose tissue caused the increased signal on T1-weighted images. The extraosseous components of the tumor contained little, if any, adipose tissue, which explained the lack of high-intensity signal on T1-weighted images. These signal changes appear to make a specific constellation of findings for the diagnosis of vertebral hemangioma with MR imaging.