Application of DWIBS in malignant lymphoma: correlation between ADC values and Ki-67 index.

objectivesWe investigated the correlation between the apparent diffusion coefficient (ADC) and Ki-67 index using diffusion-weighted whole-body imaging with background body signal suppression (DWIBS), and their utility in evaluating malignant lymphoma cell proliferation. MATERIALS AND

methodsSeventy-four patients with malignant lymphoma underwent DWIBS within 1 week before pathological confirmation. The ADC value was measured at the site of the pathological examination, and specimens were also stained with Ki-67. The ADC values and Ki-67 indices in aggressive non-Hodgkin's lymphoma (NHL), indolent NHL, and Hodgkin's lymphoma (HL) were compared using Spearman's rank correlation coefficient and the Kruskal-Wallis test.

resultsThe Ki-67 indices and ADC values were inversely correlated (r = -0.289, p = 0.0125); the differences in the Ki-67 index between aggressive NHL, indolent NHL, and HL were significant (p < 0.001); this was confirmed by the Nemenyi test except for indolent NHL vs. HL. The ADC values were significantly different between the types of lymphoma (p = 0.013); the Nemenyi test showed a significant difference only between aggressive NHL and HL.

conclusionsThe Ki-67 indices and ADC values are inversely correlated in patients with lymphoma, combining DWIBS and ADC values can evaluate the proliferation level of malignant lymphoma cells noninvasively. KEY POINTS: • By using DWIBS, malignant lymphoma cell proliferation can be assessed noninvasively. • The ADC value and Ki-67 index are significantly and inversely correlated. • The ADC values were lower in aggressive NHL than in HL. • The ADC values of aggressive and indolent NHL were not significantly different.