NCCN and ACS guidelines support breast MRI >20% lifetime risk. So a woman has to beat the 20% threshold for lifetime risk as adjusted by her current age, correct?

Yes.  The intent of the guidelines was to look for younger women with a high long term risk, which is why they used lifetime risk.  This means that older women with a high short term risk but a low lifetime risk are not eligible. MRI eligibility by age.  Percent of...

In a patient with a prior history of breast cancer does that automatically mean she has had one biopsy, but without LCIS or atypia, or will that risk factor come out in her personal history of prior breast cancer.

The ‘number of biopsies’ question is only used by Gail and TC, both of which are not applicable for breast cancer patients, so the answer would not change calculations anyway.   I would tend to say zero, as that was the count before the cancer was known. Once the...