Diagnostic value of super microvascular imaging in differentiating axillary lymph nodes: semi-quantitative and qualitative approach in primary breast cancer and suspicious axillary nodes.

BACKGROUND: The evaluation of axillary lymph nodes (ALNs) using ultrasound (US) plays a crucial role in the diagnosis and management of breast cancer. This study aims to assess the diagnostic performance of both quantitative and qualitative features of suspicious ALNs using superb microvascular imaging (SMI). To the best of our knowledge, this is the first prospective study in the literature to evaluate the largest number of suspicious ALNs using SMI and to analyze the combined diagnostic value of these findings. METHODS: Our prospective study involved 102 patients with suspicious lymph nodes in the axilla. SMI method was employed individually to assess distribution, appearance, and number of vascular structures. After histopathological or follow-up confimation, images were re-evaluated. We also examined the diagnostic value of various combinations of these vascular features. Lastly, two radiologists, each with 22 and 4 years of experience, independently reviewed the images, blinded to clinical and pathological data, to assess interobserver agreement. RESULTS: A total of 108 lymph nodes were evaluated in 102 patients, including 67 benign and 41 malignant cases. The diagnostic performance of various combinations in receiver operating characteristic (ROC) analysis revealed that the highest accuracy (78.70%) and area under the curve (AUC) value in ROC analysis were achieved by distribution-appearance combinations (AUC: 0.776, p < 0.001). Interobserver agreement was significant for both the SMI and PDUS methods. In patients diagnosed with breast cancer, the diagnostic accuracy for suspicious axillary lymph nodes reached 92.76%, with an AUC value of 0.855. CONCLUSION: In conclusion, our findings suggest that SMI facilitates more accurate identification of suspicious axillary lymph nodes prior to surgical intervention.