Objective: The purpose of this study was to assess the diagnostic correlation between indirect MR arthrography, conventional MRI, and arthroscopy in acetabular labral and cartilage lesions of the hip.
Materials and methods: Fourteen patients who underwent conventional and indirect MR arthrography with arthroscopic correlation were studied over the course of 18 months. MR studies were performed on a 1.5-T magnet. Sequences consisted of unilateral sagittal turbo spin-echo proton density fat-suppressed, axial turbo spin-echo T2 fat-saturated, and coronal turbo spin-echo proton density fat-saturated images. Whole-pelvis coronal T1 and STIR sequences were also performed. Patients received IV gadolinium contrast material and exercised for 15 minutes. Gadolinium-enhanced fat-saturated T1 sequences were obtained in three planes. Arthroscopy was performed by two orthopedic surgeons who specialize in treating hip disorders. Cases were then retrospectively reviewed by two experienced musculoskeletal radiologists who were blinded to the arthroscopic findings. Cases were examined for acetabular labral tears and chondral lesions. Extraarticular findings of femoral acetabular impingement were recorded. Unenhanced and gadolinium-enhanced images of the labrum were compared for differences and changes in diagnosis. Comparison was made between the arthroscopic and MR findings for analysis of the results.
Results: Of the 13 labral tears found at arthroscopy, 85% were detected by conventional MRI, whereas 100% were identified via indirect MR arthrography. Seventy percent of the labral tears identified on conventional MRI were better delineated by indirect MR arthrography. Identification of chondral abnormalities was not improved via indirect MR arthrography over conventional MRI.
Conclusion: IV contrast-enhanced indirect MR arthrography appears to be an effective means of hip evaluation for labral tears. It does not appear to improve detection of cartilage abnormalities when compared with conventional MRI.