The value of the improved percutaneous and intravenous contrast-enhanced ultrasound diagnostic classification in sentinel lymph nodes of breast cancer.

Background:Metastatic burden of sentinel lymph node (SLN) in breast cancer patient is the basis for the decision to choose SLN biopsy or axillary lymph node dissection (ALND). However, the diagnostic performance of the previous percutaneous contrast-enhanced ultrasound (P-CEUS) and intravenous contrast-enhanced ultrasound (IV-CEUS) pattern were not satisfied. This study aimed to establish new classification based on structural characteristics for P-CEUS and IV-CEUS of SLN in breast cancer and evaluate the diagnostic efficacy. Methods:This retrospective study included consecutive breast cancer patients who had not received neoadjuvant therapy in the First Affiliated Hospital of Sun Yat-sen University between June 2019 and December 2021. Conventional ultrasound, P-CEUS and IV-CEUS were performed. The new classification methods for P-CEUS and IV-CEUS of SLN were established based on structural characteristics of SLN. Pathology was considered as the gold standard, the diagnostic efficacy of P-CEUS, IV-CEUS and combined contrast-enhanced ultrasound in SLNs was analyzed. Results:The detection rate of SLN by P-CEUS in 368 patients was 95.42%. The P-CEUS pattern of SLNs was divided into six types. The IV-CEUS sequence was divided into three types. The IV-CEUS mode was divided into four types. Among the 438 SLNs detected by P-CEUS, 105 (23.97%) were malignant and 333 (76.03%) were benign. Among the previously classified P-CEUS, P-CEUS, IV-CEUS and combined contrast-enhanced ultrasound, the latter had the highest diagnostic efficacy (P<0.05), with sensitivity, specificity, positive predictive value, negative predictive value, accuracy and area under curve (AUC) of 81.90% (86/105), 97.30% (324/333), 90.53% (86/95), 94.46% (324/343), 93.61% (410/438) and 0.896 (0.864-0.923), respectively. Conclusions:The new classification of the P-CEUS and IV-CEUS features of SLNs was performed based on structural characteristics of lymph nodes. Compared with the previously classified P-CEUS, the new classification method has higher diagnostic performance. The combination of new classified P-CEUS and IV-CEUS is helpful to further improve the diagnostic performance of SLNs.