Quantitative assessment of bone marrow hematopoiesis using parametric magnetic resonance imaging

Spatial maps of the percentage cellularity in pelvic bone marrow were calculated at a resolution of 15.6 mm(3) from six volunteers and 10 patients treated for documented hematologic disease using a three-point Dixon MRI pulse sequence. The percentage cellularity calculation was aided by analyzing a two-dimensional feature space consisting of the apparent water fraction (W-a), and the T-2 relaxation time of water (T-2w), An extracellular water fraction was assigned to each voxel on the basis of a two-component T-2w algorithm. In six cases, the method was compared to results obtained from core biopsies or aspirates of the posterior iliac crest. The results indicate that segmentation schemes that combine high-quality phase-contrast imaging with nuclear relaxation time measurements can potentially identify the true fractional marrow volume occupied by hematopoietic elements in a variety of clinical situations.