Magnetic resonance imaging of the bone marrow after bone marrow transplantation or immunosuppressive therapy in aplastic anemia.

To compare magnetic resonance (MR) images of the bone marrow (BM) after bone marrow transplantation or immunosuppressive therapy in patients with aplastic anemia (AA), MR imaging of BM was reviewed retrospectively in 16 patients (13 males and 3 females, mean age 26 yr) with AA who completely responded clinically after transplantation or immunosuppressive therapy. The signal intensity (SI) of BM was classified into four patterns according to the increasing amount of cellular marrow, i.e., pattern I to IV. SI of MR imaging of BM exhibited an increase of cellular marrows following both transplantation and immunosuppressive therapy. Of the eight patients on transplantation, the SI of the lumbar spinal BM was pattern III in two patients and IV in six on T1-weighted and short tau inversion recovery (STIR) images. In the eight patients with immunosuppressive therapy, the SI of the lumbar spinal BM was pattern II in one, III in five, and IV in two on T1-weighted images and pattern II in one, III in four, and IV in three on STIR images. SI on MR imaging of the lumbar spinal BM showed a more cellular pattern in patients on transplantation than in those on immunosuppressive therapy.