Dear Karen D: Dense breast tissue can make mammographic interpretation difficult. A spot compression is often recommended because there is an abnormal appearance - sometimes as simple as tissue rolled over on itself. A spot compression can focus in on the area and help to clarify. It is not routine for women to have spot compression to begin with but since this has happened to you twice, it may be that you can make arrangements on your next mammogram to have them interpreted before you leave so that if you need spot compression it can be done while you are there. It depends, though on how the mammography center is run and whether the radiologist is "on site."