Abstract:Objective To analyze the reliability and validity of improved oblique-axial plane magnetic resonance imaging (MRI) for the detection of anterior talofibular ligament (ATFL) injuries in chronic lateral ankle instability. Methods Patients who underwent conventional and improved oblique-axial plane MRI followed by subsequent arthroscopy for their various ankle disorders between January 2013 to November 2015 were enrolled in this diagnostic study. The ATFL on MRI were assessed by two radiologists independently, and the results of MRI assessments were compared with the arthroscopic findings, which were used as the standard of reference. We compared The display effect of ligament length by the methods was compared, and the consistency between the observers with ICC index was evaluated. The sensitivity, specific, negative predictive value, positive predictive value, and accuracy were compared between two kinds of MRI. Results All 91 cases were recruited in our research, including 49 males and 42 females. The average age was (34.6 ± 13.2). The display effect of conventional MRI and improved oblique axis MRI had statistically significant differences (observer A: Z = -4.987, P = 0.000; observer B: Z = -4.084, P = 0.000). The ICC of conventional MRI was 0.915 (0.867, 0.946) while the ICC of improved oblique axis MRI was 0.943 (0.902, 0.987). The sensitivity and negative predictive value, positive predictive value and accuracy of improved oblique-axial plane MRI were 92%, 97%, 86%, 98%, 95% in observer A and 95%, 94%, 91%, 97% and 95% in the observer B. Conclusions For the diagnosis of anterior talofibular ligament lesion, the improved oblique axis MRI has better consistency between the observer and the higher diagnostic value of outstanding, which can display well ligament length.