All lesions detected on PET/MRI will undergo biopsy under ultrasound using fused PET/MRI and ultrasound images for guidance, and compared to histopathology. The primary outcome measure in this study is the proportion of clinically significant prostate cancers that are detected with PET/MRI compared to MRI alone. Improved detection of clinically significant prostate cancer may enable a tailored, personalized therapeutic approach, decreasing morbidity and potentially improving overall patient outcome.