T1-weighted (500/11, TR/TE) sagittal MR images of the lumbosacral spine in a 45-year-old woman before (A) and 40 days after (B) bone marrow transplantation for multiple myeloma. There is a diffuse MR pattern of marrow involvement in (A) (bone marrow plasma cells, 50%; monoclonal protein, 6.0 g/dL). On the posttreatment image, there is definite reinstitution of fatty marrow in the spine and, in particular, around the basivertebral veins, in keeping with partial response to treatment (bone marrow plasma cells, 0.5%; monoclonal protein, 1.6 g/dL).