In order to evaluate the usefullness of magnetic resonance imaging (MRI) in estimating bone marrow cellularity, we performed T1-weighted MRI of the lumbar vertebral marrow in two patients with severe aplastic anemia, before and after bone marrow transplantation (BMT). High signal intensity was detected in the bone marrow before BMT, but the bone marrow pattern of MRI became normal after BMT. MRI seems to be effective for evaluating bone marrow cellularity and recovery, and for monitoring therapeutic effects in patients with aplastic anemia before and after treatment with BMT.
