In their lifetime, 1 in 6 men will be clinically diagnosed with prostate cancer. If serum prostate specific antigen (PSA) is elevated or digital rectal exam suggests a tumor, transrectal ultrasound-guided biopsy will be performed to detect potential cancer, and assess its extent, volume and aggression. But the specificity of PSA is low, and TRUS biopsy underestimates the extent and grade of prostate cancer. MRI has a role in detecting and staging prostate carcinoma, and in evaluating men with a rising PSA after therapy.