Enhanced sagittal T1-weighted (500/10, TR/TE) MR images of the thoracic spine in a 56-year-old woman with multiple myeloma before (A) and after (B) partial response to treatment with chemotherapy. In (A), there is diffuse enhancement of the abnormal bone marrow. In (B), only a few foci of enhancing marrow indicating persistent tumor are seen (arrows). The remainder of the bone marrow does not enhance in keeping with the presence of hematopoietic marrow, fibrosis, or both. Without enhanced images, the dark appearance of the marrow in (B) could be attributed to persistent tumor.