MR arthrography of the hip joint

MR arthrography of the hip joint is usually performed after a conventional MRI has been obtained to rule out other pathologies of the hip joint as for instance bone marrow edema or osteonecrosis of the hip. MR arthrography is mainly performed as a very special investigation, and it is executed in most cases if the clinician asks for the diagnosis of a labral lesion. In very rare cases, MR arthrography of the hip is performed to image cartilage disease or osteochondrosis dissecans or free intraarticular bodies. In this paper, the indications, the technique, and the most important pathology of the hip joint--labral lesions--will be described as well as variants of the normal acetabular labrum. After a conventional MRI of the hip joint has been performed, a MR arthrography of the hip will be obtained to search for labral pathology or cartilage disease. MR arthrography is obtained after the intraarticular injection of 10-20 ml of a 0.1 mmol solution of gadopentate-dimeglumine has been performed. The intraarticular injection can either be fluoroscopic-guided or CT-guided or directly MR-guided. After the intraarticular injection, MR arthrography will be performed by the use of paracoronal and parasagittal T1-weighted spin echo or gradient echo sequences. In cases of labral lesions (degeneration, labral tear, labral detachment) or cartilage disease MR arthrography proved to be more sensitive as conventional MRI as shown in the literature. The sensitivity of MRI to detect labral pathology was reported to be about 65%, and that of MR arthrography was reported to be about 92-95% compared to surgical results. According to the current literature, MR arthrography is the most sensitive method to delineate these kind of pathologies. Therefore, the invasive technique of MR arthrography may be justified for the correct diagnosis of these kind of pathologies after other pathologic entities have been ruled out by conventional MRI.