Indirect MR arthrography: Optimization and clinical applications

PURPOSE: To evaluate and optimize a method for producing magnetic resonance (MR) images similar to MR arthrograms of multiple synovial joints with intravenous gadopentetate dimeglumine injection. MATERIALS AND METHODS: The authors examined the effects of joint motion, dose of gadopentetate dimeglumine (0.1, 0.2, and 0.4 mmol/kg), and fat saturation on the enhancement rate of the joint cavity and the degree of image contrast generated among articular structures on MR images in 14 healthy volunteers. Shoulder, elbow, wrist, hip, knee, and ankle joints of 10 volunteers were imaged with optimized parameters. Indirect MR arthrographic findings in 17 patients with joint disorders (eg, rotator-cuff tears, meniscal tears, and osteoarthritis) were compared with arthroscopic findings. RESULTS: Fat-saturated images obtained after 10 minutes of exercise and administration of 0.1 mmol/kg gadopentetate dimeglumine were similar to those obtained after intraarticular injection of contrast medium. Exercising the joint yielded the strongest joint-cavity enhancement. Increasing the dose of Contrast medium in the unexercised joint did not statistically significantly improve the contrast-to-noise ratio. Rotator cuff tears, meniscal tears, and cartilage defects were better delineated with this method than with unenhanced MR imaging and showed good correlation with arthroscopic results. CONCLUSION: Indirect MR arthrography of an exercised joint provides homogeneous enhancement and improved delineation of soft-tissue structures.