Bone marrow microcirculation analysis in multiple myeloma by contrast-enhanced dynamic magnetic resonance imaging

The aim of our study was to investigate the quantitative microcirculation p arameters amplitude A (hypothetical intravascular volume) and exchange rate constant k(21) (hypothetical vascular permeability) by contrast-enhanced d ynamic magnetic resonance imaging (dMRI) as markers of angiogenesis in mult iple myeloma (MM). Therefore lumbar spine and spina iliaca superior posteri or of 16 normal controls and 41 patients with active MM were assessed using a dMRI protocol with a pump controlled bolus infusion of Gadolinium-DTPA. Pharmacokinetic parameters, amplitude A and exchange rate constant k(21) we re calculated according to a 2-compartment model. Color-coded parameter ima ges were generated from pharmacokinetic data analysis and superimposed onto the conventional MR images. Amplitude A and k(21) parameters were signific antly increased in patients with MM compared with controls (p = 0.001; medi an A(ctr), 0.2 [range, 0.09-0.4]; median A(MM),0.93 [range, 0.2-2.2]; media n k(21ctr), 0.09 min(-1) [range, 0.03-0.9]; median k(21MM), 4.58 (range, 0. 22-23.8]). Within the group of MM patients the pattern of color-coded param eter images were found to be either of "diffuse" (n = 13, 31%) or "focal" ( n = 28, 69%) type of distribution of microcirculation. Comparison of amplit ude A in patients with "focal" vs. "diffuse" pattern of the pharmacokinetic maps revealed a significant increase in the median of amplitude A in the " focal" group. Amplitude A values allowed a classification of patients accor ding to severe osteolytic bone involvement (p = 0.023) with the best cutoff value of 0.7 for amplitude A. Downmodulation of amplitude A was observed i n a MM patient treated with standard VAD chemotherapy. Our data demonstrate that dMRI is a novel imaging technique for the detection and monitoring of MM bone lesions. It provides independent evidence for angiogenesis in MM. (C) 2001 Wiley-Liss, Inc.