Optoacoustic US May Correctly Downgrade BI-RADS Classification of Benign Breast Masses

Use of optoacoustic (OA) ultrasonography (US) may help correctly downgrade benign masses classified as BI-RADS 4a and 4b to BI-RADS 3 or 2, according to a study published in the journal Radiology.

Researchers from the Netherlands undertook a prospective, multicenter study to assess the ability of OA US in classifying benign breast masses. 

A total of 209 patients with 215 breast masses classified as BI-RADS 4a or 4b at US were reported for this study. The masses were first evaluated with US with knowledge of previous clinical information and imaging results, and from this information a US imaging–based probability of malignancy (POM) and BI-RADS category were assigned to each mass. The same masses were then re-evaluated at OA/US. During the OA/US evaluation, radiologists scored five OA/US features, and then reassigned an OA/US-based POM and BI-RADS category for each mass. BI-RADS downgrade and upgrade percentages at OA/US were assessed by using a weighted sum of the five OA feature scores.

The results showed that at OA/US, 47.9 percent (57 of 119) of benign masses classified as BI-RADS 4a and 11.1 percent (3 of 27) of masses classified as BI-RADS 4b were correctly downgraded to BI-RADS 3 or 2. Two of seven malignant masses classified as BI-RADS 4a at US were incorrectly downgraded, and one of 60 malignant masses classified as BI-RADS 4b at US was incorrectly downgraded for a total of 4.5 percent (3 of 67) false-negative findings.

The researchers concluded that at OA/US, benign masses classified as BI-RADS 4a could be downgraded in BI-RADS category, which would potentially decrease biopsies negative for cancer and short-interval follow-up examinations, with the limitation that a few masses may be inappropriately downgraded.