High-resolution ultrasonographic features of axillary lymph node metastasis in patients with breast cancer.

To determine ultrasound (US) features that most accurately predict the presence of axillary lymph node metastasis, we retrospectively analysed the results of preoperative US breast examinations of axillary lymph nodes in 425 consecutive patients who subsequently underwent surgery for invasive breast cancer. We compared the US findings with pathologic results for axillary lymph node metastasis. US features included length of the longest (L) and shortest (S) axes, L/S ratio, cortical thickness, presence of hilum and shape. The results of multivariate logistic regression analysis revealed that cortical thickness greater than 3mm was the most accurate indicator, with 4.14 times increased risk of the presence of an axillary lymph node metastasis as compared to cortical thickness less than 3mm. The absence of a hilum showed the highest specificity for axillary lymph node metastasis (94.6%), but low sensitivity.