Biopsy is Better. After an abnormal mammogram, a biopsy is the most effective way to identify breast cancer, better than four non-invasive tests—an MRI, ultrasound, PET scan and scintimammogram, says a report based on a review of 81 studies, done by the federal Agency for Healthcare Research and quality. The researchers found that for every 1,000 women who had MRIs following abnormal mammograms and did not have breast cancer, 38 would have undetected cancers. (To find out more about...