MRI of sacral ala insufficiency fracture

Plain radiographs and a computed tomography (CT) of the pelvis failed to reveal any fracture in the elder patient for whom the studies were obtained. When her groin and low back pain persisted, this and the accompanying magnetic resonance image (MRI) were obtained. Bone marrow edema consistent with an insufficiency fracture of the sacral ala (arrow) is seen on this T2 image.