Among the 154 SLNs, 73 were metastatic and 81 were reactive.The presence of SRUS perfusion defects was significantly higher in metastatic SLN (95.9%) compared to reactive SLN (72.8%) (P <0.001).In the whole SLNs, the maximum sinus distance was significantly greater in metastatic SLNs compared to reactive SLNs (1.91±1.72 mm vs. 1.22±0.81 mm, P = 0.001). Similarly, in the cortex, the maximum sinus distance was also significantly higher in metastatic SLNs (0.85±0.96 mm vs. 0.54±0.31 mm, P = 0.010).Sinus density in the whole lymph node and the lymph node cortex was significantly higher in metastatic SLN compared to reactive SLN (P=0.011 and 0.016, respectively).In terms of velocity, the maximum velocity was significantly higher in reactive SLNs (35.28±11.72 mm/s) compared to metastatic SLNs (32.07±7.66 mm/s) (P=0.048) in the whole lymph node.In predicting metastatic SLNs, the AUC for SRUS (0.824; 95% CI: 0.761-0.888) was significantly higher than that for conventional US (0.661; 95% CI: 0.596-0.726) (P < 0.001). The combination of SRUS and conventional US achieved the highest AUC (0.844; 95% CI: 0.785-0.904), which was significantly higher than conventional US alone (P < 0.001), but not significantly different from SRUS alone (P = 0.2).