The technology's positive predictive value doubled between year 3 and 4, noted Dr. Jean Weigert, from the Hospital of Central Connecticut, and colleagues.
Weigert's group investigated how breast ultrasound has continued to perform as a follow-up screening modality for women with dense tissue in the years since the law was passed. The researchers used data from two Connecticut radiology practices with five sites.
A total of 32,230 screening mammograms and 4,128 dense-breast ultrasounds were performed in the third year after the legislation, and 27,937 screening mammograms and 3,330 dense-breast ultrasounds were performed in year 4. A third of the women eligible for screening ultrasound requested it, according to Weigert and colleagues.
The cancer detection rate in both the third and fourth years was three per 1,000 women -- the same rate as in the first two years after the law was enacted. But screening breast ultrasound's positive predictive value doubled from year 3 to year 4, from 8.1% to 16.1%, the team found.