Magnetic resonance imaging of ankle syndesmotic ligament injuries: Comparison of three-dimensional isotropic intermediate-weighted fast spin echo with conventional two-dimensional imaging

Abstract

Purpose: We sought to compare the diagnostic performance of three-dimensional (3D) isotropic intermediate-weighted fast spin echo (FSE) magnetic resonance imaging (MRI) sequences with that of conventional two-dimensional (2D) FSE sequences for the assessment of syndesmotic ligament injuries associated with ankle fractures. Methods: Between January 2014 and December 2015, 37 patients who underwent both conventional 2D MRI and 3D MRI of an ankle fracture were evaluated. All patients underwent subsequent ankle arthroscopy. Two radiologists retrospectively reviewed the imaging findings of syndesmotic ligament injury, with an interval of at least 2 weeks between sessions of interpretation. Sensitivity, specificity, and accuracy were calculated for each ligament, and McNemar's paired proportion test was performed to compare the diagnostic performance. Results: Injuries of the anterior inferior tibiofibular ligament were the most common finding in the patients (31/37, 83.8%). The 3D sequences showed a sensitivity of 96.8% to 100% and a specificity of 50% to 66.7% in these injuries, whereas the 2D sequences showed a sensitivity of 96.8% to 100% and a specificity of 33.3% to 66.7% (p = 0.114-0.588). Injuries of the posterior inferior tibiofibular ligament and transverse tibiofibular ligament also showed no significant difference in diagnostic accuracy between 2D and 3D sequences. Conclusion: There was no statistically significant difference in the diagnostic performance of 3D FSE sequences compared with that of 2D FSE sequences for syndesmotic ligament injuries associated with ankle fractures. The 3D MRI can be considered for syndesmotic ligament injury instead of 2D MRI, with shortened acquisition time.