Diffusion-weighted MRI (DW-MRI) is a radiation free, non-invasive diagnostic imaging technique detecting random movement of water molecules in vivo. Extent of diffusion in fluids and tissues can be assessed quantitatively using apparent diffusion coefficient (ADC). The aim of this study was to determine usefulness of DW-MRI with ADC calculation for early prediction of tumor response in patients with non-Hodgkin lymphoma (NHL).
DW-MRI was performed in 26 patients (13 males and 13 females, mean age 55 years, range 26-76) with NHL at baseline, after 1 cycle and at the end of induction chemotherapy. The largest not necrotic lymph node was chosen as a target lesion for serial size and ADC measurement. End of treatment tumor response was categorized as complete (CR) or non-complete using revised International Working Group criteria.
Target lesion ADC (mean ± SD) increased from 0.81 ± 0.33 × 10−3 mm2/c at baseline to 1.16 ± 0.44 × 10−3 mm2/c after 1 cycle of chemotherapy resulting in average increase of 50.3 ± 48.4%. The earliest ADC increase was noted on day 3 after start of chemotherapy. Product of two perpendicular diameters of target lesion decreased from 3407.7 ± 3583.7 mm2 to 2359.2 ± 2813.2 mm2 from baseline to after 1 cycle respectively giving average decrease of 36.4 ± 22.0%. Pre-treatment ADC was significantly lower in patients with CR than non-CR – 0.65 ± 0,15 × 10−3 mm2/s and 0.94 ± 0,39 × 10−3 mm2/s respectively (p 25% predicted CR with a sensitivity of 83%, specificity of 67% and an accuracy of 75%. When two parameters were combined prediction accuracy increased to 83%.
DW-MRI with ADC calculation can be used for pretreatment and early during treatment tumor response prediction in patients with NHL. Combination of pretreatment ADC and ADC change post 1 cycle of chemotherapy increases prediction accuracy.
Clinical trial identification
Legal entity responsible for the study
N.N. Alexandrov National Cancer Center of Belarus
Ministry of Health
All authors have declared no conflicts of interest.