Evaluation of Cartilage T2 Using Loading in Situ Mri in Patients with Knee Injuries

Introduction The articular cartilage in the knee joint provides load-bearing function along with adjacent meniscus and anterior/posterior cruciate ligaments, and injury of the meniscus, cruciate ligaments and articular cartilage may result in failure in responding to normal load-bearing. Previous clinical studies showed that 80% or more patients with injury of anterior cruciate ligaments resulted in development of knee osteoarthritis within follow-up of 10 years, presumably due to sustained intraarticular mechanical disorder [1]. Therefore, evaluation of intra-articular biomechanical condition after knee injury is important to estimate risk of subsequent progression of osteoarthritis and decided appropriate treatment methods. Recent studies of MR imaging showed cartilage T2 is closely related with cartilage matrix and water content. Responsiveness of articular cartilage to compressive loading by T2 may indicate pressure distribution on the cartilage, via evaluation of dynamic changes in the collagenous architecture or water influx or efflux through cartilage [2]. We have developed a loading apparatus to apply axial load to the knee joint during MR imaging in order to simulate physiological load-bearing condition while standing. Our objectives were to examine clinical feasibility of cartilage T2 with use of loading in situ MR imaging, for evaluation of abnormal pressure distribution in patients with knee injuries, especially focusing on meniscus tear.