Detection of axillary lymph node metastasis with diffusion-weighted MR imaging

The feasibility of detecting axillary lymph node (LN) metastases with diffusion-weighted MR imaging was retrospectively evaluated. The relative ADC (with b values of 0 and 1000 s/mm2) between LNs in each axillary space was calculated (n=75). The area, the long and short diameter of the metastatic LNs were compared to those of non-metastatic LNs. The relative ADC value of metastatic LNs was significantly lower than that of non-metastatic LNs (P=.00). The long and short diameter LN diagnostic performance was superior to that of mean ADC and relative ADC (AUC: 0.84, 0.80 versus 0.64, 0.03), suggesting usefulness of diameter over ADC.