They will probably use the MRI imaging to target 3 or 4 biopsy samples from the Pirads lesion, and then they will almost certainly take about 12 additional samples in a standard pattern that covers the entire gland. The goal is to make sure they determine what is going on with the lesion, and also look for anything that did not show up on the MRI. In my case and ExoDx test indicated an elevated risk of prostate cancer but an MRI did not show anything suspicious. I went ahead with a saturation biopsy (24 samples) just to be sure and that did reveal a small amount of prostate cancer which needed to be treated.