In a double-blind, prospective study, the authors analyzed bone scintigrams and magnetic resonance (MR) images of the spine in 71 patients with histologically proved skeletal metastases. Bone scintigrams and MR images were separately reviewed by four independent observers. Bone scintigraphy permitted identification of 499 abnormal vertebrae and MR imaging, 818 abnormal vertebrae. MR imaging depicted additional abnormal vertebrae in 49 patients. The authors conclude that MR imaging is more sensitive than bone scintigraphy in detection of vertebral metastases.