This study will evaluate the feasibility of identifying changes in diffusion MRI characteristics of bone that correlates with response to therapy in men with metastatic prostate cancer.
Inclusion Criteria: * Diagnosis of prostate cancer. * Evidence of metastatic disease by bone scan. * Patients must be initiating systemic therapy for metastatic disease. * New D2 disease beginning therapy with androgen deprivation. * CRPC (Castration Resistant Prostate Cancer) beginning systemic non hormonal therapy. * Patients must be willing to provide the blood samples for the correlative markers. * Patients must be able to lie flat in an MRI (Magnetic Resonance Imaging) magnet for 30-60 minutes. * Life expectancy of 12 weeks or greater. * All patients must be informed of the investigational nature of this study and must sign an informed consent in accordance with institutional and federal guidelines. Exclusion Criteria: * Contraindication to MRI imaging. * Patients who require sedation with general anesthesia to undergo MRI imaging. * Weight greater than 275 pounds.