Geoffrey A. Sonn, M.D., from the University of California Los Angeles, and colleagues used MR-US fusion prostate biopsy in 171 men (median age, 65 years) undergoing biopsy as part of active surveillance (106 men) or due to increased prostate-specific antigen levels with a prior negative conventional biopsy (65 men). MR-US fusion prostate biopsy locates lesions by magnetic resonance imaging (MRI) and fuses it with real-time ultrasound to generate a three-dimensional prostate model to allow targeted sampling. The men also had conventional systematic biopsies taken.The researchers identified prostate cancer in 53 percent of men, of whom 38 percent had cancer with Gleason grade 7 or greater. Of these highly-aggressive cancers, 38 percent were detected only by targeted biopsy. Of the 16 men with the highest level of suspicion by MRI (image grade 5 target), 94 percent had prostate cancer.