Ultrasound strain elastography to improve diagnostic performance of breast lesions by reclassifying BI-RADS 3 and 4a lesions: a multicentre diagnostic study

Objectives: To investigate the added value of strain elastography (SE) by recategorizing ultrasound (US) breast imaging reporting and data system (BI-RADS) 3 and 4a lesions. Methods: A total of 4371 patients underwent US and SE with BI-RADS 2-5 categories solid breast lesions were included from 32 hospitals. We evaluated the elastographic images according to elasticity scores (ES) and strain ratios (SR). Three combined methods (BI-RADS þ ES, BI-RADS þ SR, BI-RADS þ ES þ SR) and two reclassified methods were used (method one: upgrading BI-RADS 3 and downgrading BI-RADS 4a, method two: downgrading BI-RADS 4a alone). The diagnostic performance and the potential reduction of unnecessary biopsies were evaluated. Results: Combining BI-RADS with SE had a higher area under the curve (AUC) than BI-RADS alone (0.822-0.898 vs 0.794, P .01). For reclassified method one, the sensitivity, specificity, and accuracy were 99.36%, 66.70%, 78.36% for BI-RADS þ ES and 98.01%, 66.45%, 77.72% for BI-RADS þ SR, and 99.42%, 66.70%, 78.38% for BI-RADS þ ES þ SR, respectively. For reclassified method two, the sensitivity, specificity, and accuracy were 99.17%, 70.72%, 80.87% for BI-RADS þ ES and 97.76%, 81.75%, 87.46% for BI-RADS þ SR, and 99.23%, 69.83%, 80.32% for BI-RADS þ ES þ SR, respectively. Downgrading BI-RADS 4a alone had higher AUC, specificity, and accuracy (P .01) and similar sensitivity (P .05) to upgrading BI-RADS 3 and downgrading BI-RADS 4a. Combining SE with BI-RADS could help reduce unnecessary biopsies by 17.64%-55.20%. Conclusions: Combining BI-RADS with SE improved the diagnostic performance in distinguishing benign from malignant lesions and could decrease false-positive breast biopsy rates. Downgrading BI-RADS 4a lesions alone might be sufficient for achieving good diagnostic performance.