Dear Mmusic4fun: I have discussed your situation with a number of experts in the field. In general, no examination is done for other functioning nipples unless a problem is identified (lump is felt). There really is no screening done routinely in these situations. Ultrasound could be done if there is a problem.
I looked into it and CT scan can't be adjusted to pick up the microcalcifications
It's a very interesting question, and one I've not heard mention of before. Since it was the calcifications that led to the diagnosis, one would first want to try simply to get mammographic-type images. I'd think at least some could be fit into the machine. Failing that, CT scan could likely be adjusted to try to see calcifications, but the sensitivity is far less than that of mammogram. I think that if I, as a surgeon, were asked to advise a patient in this circumstance, I'd strongly consider removing the supranumery nipples. It would be relatively minor surgery, with mild discomfort, and minimal risk.