Magnetic resonance imaging of the musculoskeletal system. II. The hip.

Magnetic resonance (MR) imaging of the hip joint and adjacent structures can provide valuable information under many clinical circumstances. After plain radiography, MR imaging is arguably the modality of choice for the detection of osteonecrosis, occult fractures, primary and secondary neoplasms, and in the assessment of some soft tissue abnormalities. The accuracy of MR imaging is dependent on technical factors, such as magnet field strength, surface coils, and sequence selection. Low resolution MR images generally are satisfactory for screening for osteonecrosis and for the evaluation of large bone or soft tissue abnormalities. Tailoring an examination with high resolution images, specialized sequences, or contrast may add useful information, particularly if a detailed evaluation of the joint is desired. Tailoring of the examination by an experienced radiologist requires adequate clinical information, so communication between the referring physician and radiologist is crucial for optimal results. Finally, MR imaging and radiographs are complementary examinations; MR images of the hip should not be interpreted without having recent radiographs available for comparison.