Imaging therapeutic response in human bone marrow using rapid whole-body MRI
Whole-body imaging of therapeutic response in human bone marrow was achieved without introduced contrast agents using diffusion-weighted echo-planar magnetic resonance imaging of physiologic water. Bone marrow disease was identified relative to the strong overlying signals from water and lipids in other anatomy through selective excitation of the water resonance and generation of image contrast that was dependent upon differential nuclear relaxation times and self-diffusion coefficients. Three-dimensional displays were generated to aid image interpretation. The geometric distortion inherent in echo-planar imaging techniques was minimized through the acquisition of multiple axial slices at up to 12 anatomic stations over the entire body. Examples presented include the evaluation of therapeutic response in bone marrow during cytotoxic therapy for leukemia and metastatic prostate cancer and during cytokine administration for marrow mobilization prior to stem cell harvest.