Effectiveness of diffusion-weighted imaging in predicting cervical lymph node metastasis in head and neck malignancies.

OBJECTIVE

The aim of this study was to evaluate the effectiveness of diffusion-weighted imaging (DWI) in predicting cervical lymph node metastasis in head and neck malignancies.

STUDY DESIGN

Of the 67 patients with head and neck malignancies included in the study, 36 patients (the DWI group) underwent DWI examination with magnetic resonance imaging (MRI) of the cervical lymph nodes, and 31 patients (the conventional MRI group) underwent MRI only. Radiologists classified the lymph nodes as "metastatic" or "benign" in the DWI group by using MRI features and the apparent diffusion coefficients (ADCs) calculated from DWI, and in the conventional MRI group with MRI only. Histopathologic diagnosis of the nodes was the gold standard.

RESULTS

The average ADC value of metastatic lymph nodes was significantly lower than that of benign lymph nodes (P = .020). An optimal threshold ADC value effectively distinguished the ADCs of metastatic versus benign lymph nodes (P = .003). Diagnostic performance was significantly better in the DWI group (P = .044), with significantly higher values for sensitivity, positive predictive value, and area under the receiver operating characteristic curve (P ≤ .039).

CONCLUSIONS

ADC is effective in distinguishing metastatic lymph nodes from benign lymph nodes. The addition of ADC values to the morphologic evaluation of MRI results in significantly better diagnostic outcomes compared with evaluation of MRI alone.