Current knowledge and importance of dGEMRIC techniques in diagnosis of hip joint diseases

Accurate assessment of early hip joint cartilage alterations may help optimize patient selection and follow-up of hip joint preservation surgery. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is sensitive to the glycosaminoglycan content in cartilage that is lost early in the development of osteoarthritis (OA). Hence, the dGEMRIC technique holds promise for the development of new diagnostic and therapeutic procedures. However, because of the location of the hip joint deep within the body and due to the fairly thin cartilage layers that require high spatial resolution, the diagnosis of early hip joint cartilage alterations may be problematic. The purpose of this review is to outline the current status of dGEMRIC in the assessment of hip joint cartilage. A literature search was performed with PubMed, using the terms "cartilage, osteoarthritis, hip joint, MRI, and dGEMRIC", considering all levels of studies. This review revealed that dGEMRIC can be reliably used in the evaluation of early stage cartilage pathology in various hip joint disorders. Modifications in the technique, such as the operation of three-dimensional imaging and dGEMRIC after intra-articular contrast medium administration, have expanded the range of application. Notably, the studies differ considerably in patient selection and technical prerequisites. Furthermore, there is a need for multicenter prospective studies with the required technical conditions in place to establish outcome based dGEMRIC data to obtain, in conjunction with clinical data, reliable threshold values for normal and abnormal cartilage, and for hips that may benefit from conservative or surgical treatment.