Dynamic contrast-enhanced MRI for assessing the disease activity of multiple myeloma: A comparative study with histology, proangiogenic cytokines and clinical markers

Abstract

6719 Background: Dynamic contrast-enhanced MRI (dMRI) of the bone marrow has been used for assessing treatment response in multiple myeloma (MM). Aim of this study was to examine whether parameters of dMRI reflect the degree of infiltration and vessel density in corresponding bone marrow biopsy specimens. Furthermore levels of proangiogenic cytokines in peripheral blood and bone marrow were compared with findings of dMRI. Methods: The pelvis of 24 patients with MM was examined using Gd-DTPA-enhanced dMRI. Biopsy was obtained from the spina iliaca posterior superior. Using a two-compartment model, the parameters amplitude A and exchange rate constant k21 in the biopsied region were calculated and compared with the histological and clinical data. The proangiogenic cytokines Hepatocyte Growth Factor (HGF), Vascular Endothelial Growth Factor (VEGF) and Basic Fibroblast Growth Factor (bFGF) were measured in peripheral blood and bone marrow of 36 patients. The results were correlated with dMRI parameters. Results: DMRI parameters were significantly higher in lesions with marked infiltration than with mild or no infiltration (p<0.05). Amplitude A, but not exchange rate constant k21 was higher in lesions with high vessel-density at histology (p=0.01). Higher levels of the exchange rate consant k21 were found in presence of increased serum immunoglobulins. We detected a significant positive correlation of HGF concentration in peripheral blood with amplitude A of the lumbar spine (p = 0,05). Conclusions: Increased contrast uptake in the bone marrow of MM patients indicates at least moderate tumor involvement. The contrast enhancement correlates with the degree of plasma cell infiltration and vessel-density. The correlation between HGF and bone marrow microcirculation as detected by dMRI supports the role of HGF in regulation of bone marrow microcirculation and angiogenesis in MM. No significant financial relationships to disclose.