Whole-body diffusion-weighted MRI for evaluation of response in multiple myeloma patients following bortezomib-based therapy: A large single-center cohort study

Abstract

PurposeTo determine the feasibility of whole-body diffusion-weighted imaging (WB-DWI) MRI for evaluation of response in patients with multiple myeloma (MM) following bortezomib-based therapy and to explore the direction of apparent diffusion coefficient (ADC) changes upon treatment. MethodSeventy-two MM patients who underwent WB-DWI MRI before and after bortezomib-based chemotherapy (21 weeks) were evaluated retrospectively. The estimated tumor volume (eTV) and ADCmean values before and after chemotherapy were calculated and compared between deep and non-deep responders. Predictive value of baseline ADCmean was calculated to predict the trend of ADCmean change following treatment. ResultsFifty-five patients were classified as deep responders, and 17 cases were assigned as non-deep responders. For 327 focal lesions (FLs), the ADCmean value was significantly increased from baseline to post-treatment. However, the ADCmean value was significantly decreased following treatment in 846 representative diffuse lesions. Diffuse lesions showed a significantly decreased ADCmean value in deep responders, whereas no significant variation in ADCmean value in FLs was found between deep and non-deep responders. Baseline ADCmean at a specific value (0.808 × 10−3 mm2/s) yielded a maximum specificity (68.05%) and sensitivity (54.09%) in predicting increase of post-treatment ADCmean. ConclusionsThe ADCmean value was significantly decreased in MM patients with diffuse pattern, while it was significantly increased in those with focal pattern following bortezomib-based treatment. WB-DWI MRI could be used to discriminate deep response to induction treatment in MM patients with diffuse infiltration pattern. Baseline ADCmean value might have a potential to predict the trend of ADCmean change following treatment.