Injured lateral ankle ligaments: Technique and assessment of MRI

Purpose: To evaluate the visualisation and extent of injury of lateral ankle ligaments using MRI. Methods: 56 patients with the clinical diagnosis of sprained ankles were investigated. Evaluation of the anterior (AFTL) and posterior fibulotalar ligament (PFTL) was performed with the foot in dorsiflexion (20 degrees) and of the fibulo calcanear ligament (FCL) in plantarflexion (45 degrees). Axial T-1 w-SE and T(2)w-TSE images were obtained. Full-length visulaisation of ligaments in one slice and the extent of injury were evaluated. 12 ankle injuries were confirmed by operation. Results: With MRI full-length visualisation of lateral ankle ligaments was possible in 86%. A partial/complete rupture of the AFTL was noticed in 33/64% and of the FCI in 29/39%, and of the PFTL in 27/5%. Sensitivity/specificity of MRI when compared to surgery was 100/100% for injuries of the AFTL, 64/100% for the FCL, and 33/78% for the PFTL. Conclusion: Full-length visualisation of ligaments, achieved by appropriate combination of foot position and imaging plane is essential for evaluation of injured ankle ligaments on MRI. High assessment for ligamentous injuries on MRI in relation to surgery was found.