MR Imaging of Knee Osteoarthritis and Acute Knee Injuries

The study will examine the pathophysiology of bone marrow changes, relationship between trabecular bone and cartilage changes; and evaluate T1p relaxation methods and its' relating to cartilage loss. The protocol is geared towards sequences utilizing 3 Tesla magnetic resonance imaging (MRI) that will enable the measures of cartilage volume and T2. Measures cartilage volume and T2 are more established MR methods for studying osteoarthritis (OA). All OA and Anterior cruciate ligament (ACL) subjects will undergo MR imaging of the knee joint at 3 Tesla at baseline,, and three annual follow up time points. Regions of interest will include the total tibial and femoral cartilage, and sub-division such as the medial and lateral compartments of the tibial and femoral cartilage to account for localized disease activity and progression. Bone marrow edema size, MR spectroscopy based marrow fat/water content, and trabecular bone microarchitecture underlying the edema will be measured in the OA and ACL groups to determine whether there is any distinction between these measures in OA and in traumatic ACL injury, cross-sectionally and longitudinally, and their relation to cartilage loss and OA progression.