abnormal u/s

Earlier this year I had an abnormal mammogram (BI-RADS 4) with findings of microcalcifications-biopsy was negative. Last week I had a screening ultrasound with abnormal findings in the same breast. I wasn't given much information other than there were "two areas of concern" and I was told to come back for a diagnostic ultrasound and a diagnostic mammogram. I had questioned if the abnormalities could just be tissue changes from the biopsy-the person I was speaking with couldn't answer this. In my "research" (i.e. reading everything I can online), I can't find anything about this. I also don't see a protocol anywhere for a mammogram after an abnormal ultrasound. Has anyone heard of a mammogram following the ultrasound? Thx!