Objective: To compare the efficacy of contrast-enhanced ultrasound enabled reclassification of Breast Imaging Reporting and Data System (CEUS-BI-RADS) with MRI in the diagnosis of breast lesions with calcification. Methods: A total of 52 breast lesions with calcification from 51 patients were detected by ultrasound as hyperechoic foci and categorized as BI-RADS 3–5. The 51 patients further underwent CEUS scan and MRI. The ultrasound-BI-RADS combined with CEUS 5-point score system redefined the classification of BI-RADS which was called CEUS-BI-RADS. The diagnostic efficacy of three methods was assessed by receiver operating characteristic (ROC) curve analysis. Histopathological assessment used as the gold-standard. Results: The sensitivities of Ultrasound-BI-RADS, MRI classification of BI-RADS (MRI-BI-RADS) and CEUS-BI-RADS were 85%, 90% and 95% without significant difference among the three modalities (p > 0.05). The diagnostic specificities of ultrasound-BI-RADS, MRI-BI-RADS and CEUS-BI-RADS were 78.1%, 78.1% and 96.8%, respectively (p < 0.05); and the accuracy were 80.7%, 82.6% and 96.1% for ultrasound-BI-RADS, MRI-BI-RADS and CEUS-BI-RADS, respectively (p < 0.05). The area under ROC (AUROC) in differentiation of breast lesions with calcification was 0.945 for CEUS-BI-RADS, 0.907 for MRI-BI-RADS and 0.853 for ultrasound-BI-RADS, with no significant difference among the three modalities (p > 0.05). Conclusion: The CEUS-BI-RADS has a better diagnostic efficiency than MRI-BI-RADS in the differentiation of the breast lesions with calcification. Advances in knowledge: •CEUS is a better method in differentiation of breast lesions with calcification. •CEUS-BI-RADS increases the efficiency of diagnosis compared to MRI.

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.