Hip Magnetic Resonance Arthrography Using Normal Saline Is Less Accurate Than Using a Gadolinium-Based Contrast Agent

Area of Science:

• Radiology
• Orthopedic Imaging
• Diagnostic Imaging

Background:

• Hip magnetic resonance (MR) arthrography is a key imaging modality for diagnosing intra-articular hip pathologies.
• Evaluating the diagnostic performance of different contrast agents is crucial for optimizing imaging protocols.

Purpose of the Study:

• To compare the diagnostic performance of hip MR arthrography using gadolinium-based contrast agent (GBCA) versus normal saline (NS) for intra-articular pathologies.
• To assess the reliability of these imaging techniques in detecting labral tears, cartilage abnormalities, and ligamentum teres tears.

Main Methods:

• Retrospective analysis of 37 patients (38 hips) who underwent GBCA-hip MR arthrography and 30 patients (30 hips) who underwent NS-hip MR arthrography.
• Independent evaluation of MR images by two blinded radiologists for labral tears, cartilage abnormalities, and ligamentum teres tears.
• Diagnostic performance was compared against arthroscopic findings, with intra- and inter-reader reliability assessed using kappa values.

Main Results:

• Intra-reader reliability ranged from moderate to almost perfect (k = 0.510–0.840), and inter-reader reliability ranged from moderate to substantial (k = 0.441–0.695) for both techniques.
• Diagnostic accuracy for labral tears was 81.6–92.1% for GBCA and 66.7–73.3% for NS.
• Accuracy for cartilage abnormalities was 68.4–86.8% (GBCA) vs. 63.3–70.0% (NS), and for ligamentum teres tears was 68.4–76.3% (GBCA) vs. 50.0–56.7% (NS).

Conclusions:

• Normal saline (NS)-hip MR arthrography may be less accurate than gadolinium-based contrast agent (GBCA)-hip MR arthrography for diagnosing intra-articular hip pathologies.
• GBCA-hip MR arthrography demonstrates superior diagnostic performance, particularly for labral and ligamentum teres tears.
• The findings support the use of GBCA for enhanced diagnostic yield in hip MR arthrography.