The usefulness of the oblique coronal plane in knee MRI on the evaluation of the posterior cruciate ligament

Abstract

Background Imaging findings of posterior cruciate ligament (PCL) injury may be equivocal, particularly when the patient has suffered a partial ligament tear. Some PCLs are positioned more horizontally, making it difficult to diagnose injury based on routine imaging planes alone due to partial volume artifact. Purpose To evaluate the diagnostic accuracy of combining oblique coronal imaging (PCL view) with traditional orthogonal views for PCL evaluation. Material and Methods This retrospective study included 20 patients with PCL injury and 43 patients with intact PCL who underwent PCL view imaging. Anatomic identification of PCL pathology on the orthogonal magnetic resonance imaging (MRI) sequences and PCL views was evaluated. Subjective scoring of the PCL was performed by two radiologists who assessed the possibility of a PCL tear based on an entire length view, an entire width view, and margin sharpness according to a 4-point scale. Diagnostic accuracy using these two views was evaluated by calculating the sensitivity, specificity, and accuracy. Arthroscopic and clinical findings were used as the reference standard. Results Total scores for the PCL view were higher than those of orthogonal views ( P < 0.001). Both readers found that anatomic identification using the full width view and sharp margin to be superior using the PCL view compared with the orthogonal views ( P < 0.001). The specificities and accuracies were higher in cases where an additional PCL view was provided, but did not show statistical significance. Conclusion PCL view provides better anatomic evaluation of the PCL and mild improvement in the specificity and accuracy.