Object: To determine whether apparent diffusion coefficient (ADC) measurements allow discrimination of normal lymph nodes from lymphomatous lymph nodes, and indolent lymphomas from aggressive lymphomas in patients with non-Hodgkin lymphoma (NHL).
Materials and methods: Eighteen healthy volunteers and thirty-two patients with newly diagnosed NHL (indolent: n = 16; aggressive: n = 16) underwent diffusion-weighted imaging. ADCs of normal lymph nodes were compared to those of lymphomatous lymph nodes, and ADCs of indolent lymphomas were compared to those of aggressive lymphomas. Receiver operating characteristic (ROC) analysis was performed when ADCs were significantly different between two of the aforementioned groups.
Results: ADCs (in 10(-3) mm(2)/s) of lymphomatous lymph nodes (0.70 ± 0.22) were significantly lower (P < 0.0001) than those of normal lymph nodes (1.00 ± 0.15). Area under the ROC curve was 0.865. Sensitivity and specificity were 78.1 and 100% when using an optimal cutoff ADC value of 0.80. On the other hand, ADCs of indolent lymphomas (0.67 ± 0.21) were not significantly different (P = 0.2997) from those of aggressive lymphomas (0.74 ± 0.23).
Conclusion: ADC measurements show promise as a highly specific tool for the discrimination of normal lymph nodes from lymphomatous lymph nodes, but appear to be of no utility in differentiating indolent from aggressive lymphomas.