Comparison of accuracy and interreader agreement in side-by-side versus independent evaluations of MR imaging of the medial collateral ligament of the elbow

Rationale and Objectives. The authors compared independent and side-by-side evaluation of magnetic resonance (MR) images of the medial collateral ligament (MCL) of the elbow, with regard to sensitivity, specificity, and interreader agreement. Materials and Methods. Six MR imaging sequences were used to image the MCLs in 28 cadaveric specimens, eight with surgically created lesions. Two reading methods were used. For independent evaluation, the images were first evaluated independently and rated on a five-point scale by two musculoskeletal radiologists experienced in interpreting MR images and blinded to the MCL integrity. The images were then reevaluated on the same scale by both readers after at least 2 weeks, with images from all six sequences shown side by side. For each MR sequence and reading method, the sensitivity and specificity were estimated nonparametrically, and differences were tested with the McNemar test. Interreader agreement was assessed with a κ statistic, and differences were tested with Z and χ² tests after adjustment for the dependence structure between correlated κ statistics. Results. For all sequences, side-by-side evaluation generally yielded higher specificity than independent evaluation, as well as better agreement between readers. Conclusion. Observer performance is superior when multiple MR imaging pulse sequences are reviewed simultaneously rather than independently and separately. Side-by-side review of different MR pulse sequences enabled higher accuracy and lower interreader variability for evaluation of the elbow MCL. These findings have implications for the design of studies to optimize MR imaging protocols by using multiple pulse sequences and multiple readers.