Accuracy of classification of breast ultrasound findings on criteria used for description in BI-RADS for breast ultrasound

Objective: The aim of this study was to assess the accuracy of categorization based on scoring breast ultrasound findings for malignancy on analogue criteria used for BI-RADS breast ultrasound.

Materials and methods: Breast ultrasound was performed in 2462 patients at our unit. Sonographic findings were scored using analogue criteria as in BI-RADS for breast ultrasound (mass shape, margin, orientation, posterior acoustic, lesion boundary, echo pattern). Each lesion was described using these features and categorized in the categories 1 to 5 according to BI-RADS for breast ultrasound. Final categorization and biopsy results were correlated.

Results: In twenty-two patients (0.9%) breast ultrasound was not evaluable because of extreme density of tissue. Normal breast ultrasound belonging to category 1 was found in 871 (35.4%) patients. Simple cysts classified in category 2 were obtained in 712 (28.9%) women. In 491 (19.9%) patients solid masses with criteria for benignity (category 3) were found. Suspect appearing masses were obtained in 225 (9.1%) and highly suggestive for malignancy were findings in 141 (5.7%) patients, according to category 4 and 5, respectively.

Histologic examinations were obtained in 84 (17.1%) masses form category 3, in 97 (43.1%) form category 4 and 106 (75.2%) from category 5, respectively. Accordingly, the rate of malignant findings was 1% (n=1) in category 3, 17% (n=16) in category 4 and 94% (n=100) in category 5 findings.

Conclusion: Scoring breast ultrasound findings for malignancy on criteria used for BI-RADS breast ultrasound has a high accuracy which is comparable to that obtained by BI-RADS for mammography.