A New Contrast-Enhanced Ultrasound (CEUS) Reporting and Data System for Breast Lesions.

OBJECTIVE: To develop and validate a breast imaging reporting and data system (BI-RADS) based on conventional ultrasonography (US) and contrast-enhanced US (CEUS) to stratify the malignancy risk of breast lesions and reduce unnecessary punctures. MATERIALS AND METHODS: This retrospective multicenter study evaluated 1465 patients with 1624 breast lesions who underwent conventional US, CEUS and received a final diagnosis from three centers. Patients from Center 1 were randomized into a training set (70%) and internal validation set (30%). Patients from Center 2 and Center 3 formed external validation sets. Qualitative US features of the breast lesions were analyzed with univariable and multivariable logistic regression. By rounding the regression coefficients of the multivariable logistic analysis to obtain scores, we developed the CEUS BI-RADS. The performance of CEUS BI-RADS in terms of discrimination, calibration and clinical utility was evaluated by receiver operating characteristic curves, calibration curves and decision curve analysis, respectively. RESULTS: In the internal validation set, the area under the receiver operating characteristic curve value of CEUS BI-RADS was significantly higher than that of conventional US BI-RADS (0.95 [95% confidence interval (CI): 0.92, 0.97] vs. 0.80 [95% CI: 0.76, 0.85], p < 0.001). Moreover, CEUS BI-RADS yielded a considerably better sensitivity (90% [122/135] vs. 76% [103/135]), specificity (80% [205/255] vs. 73% [187/255]), positive predictive value (71% [122/172] vs. 60% [103/171]) and negative predictive value (94% [205/218] vs. 85% [187/219]) than that of conventional US BI-RADS (p < 0.05 for all). Significantly also, the unnecessary biopsy rate declined from 40% (68/171) to 29% (50/172) (p = 0.037). CONCLUSION: A new, practical BI-RADS based on the features of conventional US and CEUS was developed, which had better diagnostic value than existing BI-RADS. CLINICAL RELEVANCE STATEMENT: The CEUS BI-RADS, which combined the features of conventional US and CEUS, significantly reduced the rate of unnecessary biopsy of breast lesions while maintaining relatively high sensitivity and specificity, showing its potential in alleviating patients' anxiety, reducing the burden on medical resources and improving diagnostic efficiency.