Application value of diffusion weighted whole body imaging with background body signal suppression in monitoring the response to treatment of bone marrow involvement in lymphoma

Purpose To investigate the application value of diffusion weighted whole body imaging with background body signal suppression (DWIBS) in monitoring the response to treatment of bone marrow involvement in lymphoma. Materials and Methods Twenty-one lymphoma patients with bone marrow involvement underwent 1.5 Tesla DWIBS before chemotherapy and after the second chemotherapy session (median interval, 8 weeks; range 7–11 weeks). Apparent diffusion coefficient (ADC) values of bone marrow lesions were measured before and after treatment. The difference in ADC values before and after treatment in responders and nonresponders was analyzed. Results Seventy-three cases of bone marrow lesions were diagnosed in 21 lymphoma patients before the treatment. After the second chemotherapy session, 18 patients (57 lesions) and 3 patients (9 lesions) were categorized into the responder and nonresponder group, respectively. The mean pretreatment ADC value of all lesions was 0.90 ± 0.39 × 10−3mm2/s, of which the mean ADC values of the responder group and nonresponder group were 0.92 ± 0.40 × 10−3mm2/s and 0.79 ± 0.29 × 10−3mm2/s, respectively (between-group difference: t = -0.94; P = 0.351). The posttreatment ADC value of the responder group significantly increased (66.39% ± 83.11%; P < 0.001) while the posttreatment ADC value of the nonresponder group slightly increased (5.32% ± 17.31%). The difference in the rate of change of ADC values in the responder and nonresponder groups before and after the treatment was significant (P < 0.05). Conclusion DWIBS in combination with the measurement of ADC values enabled a good short-term response evaluation for bone marrow involvement in lymphoma. However, the pretreatment ADC value indicated no significant predictive value for responses to the treatment. J. Magn. Reson. Imaging 2016;44:1522–1529.