Accurate diagnosis of axillary lymph node metastasis using contrast-enhanced ultrasonography with Sonazoid.

Axillary lymph node enlargement following sentinel lymph node biopsy (SLNB) is often difficult to accurately diagnose. In keeping with the characteristically tortuous and aberrant pattern of tumor neovasculature, metastatic lymph nodes exhibit peripheral and mixed vascularity, resulting in a microvasculature that is often difficult to visualize. Contrast-enhanced ultrasonography (CEUS) with Sonazoid, a new generation contrast agent for ultrasonography, allows for the visualization of lymph node microvessels and may enable a more accurate evaluation of lymph node metastasis. This is a case report of axillary lymph node enlargement following SLNB, in which CEUS with Sonazoid resulted in an accurate diagnosis. On the basis of our experience with this case, we have initiated a clinical trial to evaluate the detection of lymph node metastasis through the use of CEUS in breast cancer patients.