diagnostic efficacy of diffusion-weighted magnetic resonance imaging (dwi) in the differentiation of benign and malignant cervical lymphadenopathies

Background: pre-operative differentiation of benign from malignant cervical adenopathies remains a challenge. several studies indicate parameters to discriminate between benign and malignant lymph nodes, which has not yet been enough. objectives: the aim of the current study was to assess the diagnostic efficacy of diffusion-weighted mr imaging (dwi) to differentiate benign from malignant cervical lymph nodes. patients and methods: in all patients, we assessed axial and coronal fast spin echo t2 and t1-weighted images and t1-weighted after contrast injection. dwi sequences were implemented before contrast injection, in axial and coronal planes (b factor of 50, 500 and 1000 s/mm^2) and the apparent diffusion coefficient (adc) maps were reconstructed. data were assessed in mixed model analysis and results were compared with postoperative histopathologic findings. results: thirty seven subjects were enrolled, 10 with benign lymphadenopathy and 27 patients with malignant lymphadenopathies before treatment. the mean adc of the benign neck lymph nodes was (1.00 ± 0.34) * 10^-3 mm^2/s, while it was (0.76 ± 0.16) * 10^-3 mm^2/s in malignant ones (p = 0.058). the mean adc of the metastatic nodes was (0.81 ± 0.14) * 10^-3 mm^2/s, while it was (0.56 ± 0.04)* 10^-3 mm^2/s in lymphoma (p < 0.001). the mean adc of poorly differentiated metastatic nodes was significantly lower than that of good and moderately differentiated ones [(0.86±0.13)*10^-3 mm^2/s vs. (0.66±0.02)* 10^-3 mm^2/s respectively; p = 0.001]. the area under the roc curve of adc was 0.69 [95%ci = 0.52 - 0.83]. considering cut off points of 0.6 * 10^-3, 0.95 * 10^-3, and 1.2 * 10^-3 yielded sensitivities were 15%, 92.5%, and 100%, respectively; while, in these cutoff points, specificities were 80%, 50%, and 40%, respectively. conclusion: dwi could be considered as an important diagnostic tool to differentiate enlarged cervical lymphadenopathies.