Patients with Breast Cancer: Differences in Color Doppler Flow and Gray-Scale US Features of Benign and Malignant Axillary Lymph Nodes

PURPOSE To document differences in color Doppler flow and gray-scale ultrasonographic (US) features between benign and malignant axillary lymph nodes in women with primary breast cancer. MATERIALS AND METHODS The longitudinal-transverse axis ratio and hilar status on color Doppler flow and gray-scale US images were prospectively studied for each of 145 axillary nodes in 135 women (74 palpable nodes in 69 women, 71 nonpalpable nodes in 66 women) with primary breast cancer. Intranodal flow distribution was described as peripheral, central, or central perhilar. Resistive and pulsatility indexes and peak systolic velocity were documented. For comparison of benign and malignant features, nodes were divided into three groups: palpable and nonpalpable, palpable, and nonpalpable. RESULTS Color flow was demonstrated equally well in benign and malignant axillary lymph nodes for all three groups. For all nodes, peripheral flow was significantly higher in malignant (118 of 153 nodes [77%]) than benign (45 of 160 nodes [28%]) nodes (P <.001); central flow and central perhilar flow were significantly greater (P <.002 and <.001, respectively) in benign than malignant nodes. Similar differences were not observed in nonpalpable nodes. The mean longitudinal-transverse axis ratio (+/- SD) was significantly lower in malignant (1.8 +/- 0.6) than benign (2.6 +/- 0.8) nodes. Logistic regression analysis showed peripheral, central, and central perhilar flow and the mean longitudinal-transverse axis ratio to be significant independent predictors of malignancy. CONCLUSION Color Doppler flow and gray-scale US features applicable to the identification of disease in palpable axillary nodes in patients with breast cancer are not applicable to nonpalpable nodes.