ESTIMATION OF BONE-MARROW CELLULARITY BY MEANS OF VERTEBRAL MAGNETIC-RESONANCE

Background and Objective. A magnetic resonance (MR) signal shows an in verse correlation with bone marrow cellularity. In this study, we inve stigated the possibility of estimating the degree of bone marrow cellu larity by means of this non-invasive technique. Methods. In 25 patient s with different hematological disorders and homogeneous bone marrow d istribution, the percentage of bone marrow cellularity was compared to the MR signal of four middorsal vertebrae in T-1 sequence. As interna l control, the MR signal of the mid-dorsal spinal cord region was used . The results were expressed as the MR signal ratio (great mean MR sig nal of four vertebrae/MR signal of the spinal cord). Results. The corr elation coefficient (r) between both parameters was -0.93 (p<0.0001). All observed values fell within the 90% limits of predicted values. Th e mean difference between observed and predicted bone marrow cellulari ty was 5.6 (SD 4.0)%. Interpretation and Conclusions. The measurement of the MR signal is not easy to standardize since it depends to a larg e degree on the control employed. The spinal cord proved to be a satis factory internal control of the MR signal. Within defined conditions, MR can be useful for a rough estimate of bone marrow cellularity in se veral clinical situations, such as analysis of tumor burden for progno sis of some leukemias and the evaluation of response to therapy in bot h proliferative and hypoplastic disorders. (C) 1997, Ferrata Storti Fo undation.