Bone marrow segmentation in leukemia using diffusion and T-2 weighted echoplanar magnetic resonance imaging

Magnetic resonance images of leukemic bone marrow were acquired over large regions of the pelvis and lower abdomen with minimal interference from over lying tissues using diffusion and T-2 weighted echo planar imaging. Data ac quisition times were on the order of 1 min for scanning volumes of up to 25 1 at a spatial resolution of 31 mu l. A survey of 21 patients with leukemi a and eight healthy adult volunteers was undertaken to determine the magnit ude of the observed effect and its dependence upon specific pathologies. Th e acquisition methods yielded high quality segmentation of leukemic bone ma rrow prior to therapy in seven of seven patients with acute lymphocytic leu kemia, chronic lymphocytic leukemia or chronic myelogenous leukemia, and wh o had hypercellular (>95%) bone marrow at the time of the study. The qualit y of the segmentation was sufficient to allow the use of maximum intensity projection images which afforded a convenient evaluation of both intra- and extramedullary disease. The measured signal-to-noise ratios agreed with a theoretical estimate that accounted for the percentage cellularity, T-2 rel axation time of water, and self-diffusion coefficient of water in iliac bon e marrow. In addition, the mean signal-to-noise ratios from iliac marrow we re strongly dependent upon the time after the initiation of chemotherapeuti c regimens, implying that the methods may be useful for therapeutic monitor ing. Copyright (C) 2000 John Wiley & Sons, Ltd.