Magnetic Resonance Whole Body Diffusion-Weighted Imaging in Finding Bone or Lymph Node Metastasis in Participants With High-Risk Prostate Cancer

PRIMARY OBJECTIVES: I. To compare accuracies of whole body magnetic resonance imaging (MRI) versus bone scan plus computed tomography (CT) scan in detecting bone or lymph node metastasis in high risk prostate cancer patients. OUTLINE: Participants undergo standard of care bone scan, CT of the abdomen and pelvis, and pelvic MRI. Participants also undergo magnetic resonance whole body (WB)-diffusion-weighted imaging (DWI) over 20-30 minutes.