Twelve patients with osteoarthritis of the knee will undergo Geniculate Artery Embolization for treatment of knee pain. Prior to the procedure, patients will undergo MRI imaging of the affected knee which will include contrast enhanced images and dynamic contrast enhanced images. The MRI will measure the degree of abnormal blood flow in the synovial lining of the knee joint as well as change in the knee joint structure found in osteoarthritis. Patients will be followed at 1, 6, and 12 months after the procedure, and knee pain as well as medication usage will be assessed at each interval. At the 6-month visit, patients will undergo a second MRI with contrast that will be used to compare the changes in blood flow and knee joint structure.