Achilles Tendon Tear: AI-Powered MRI Analysis

On sagittal T2-fat-saturated or STIR sequences, partial tears show focal intratendinous hyperintensity with maintained tendon continuity and increased AP diameter, while complete ruptures display a fluid-filled gap between proximal and distal stumps. The tendon gap size, measured in millimetres on sagittal images, guides surgical planning. Axial PD-FS images clarify the cross-sectional involvement percentage, distinguishing central-core versus peripheral partial tears. Peritendinous fluid and reactive edema in Kager's fat pad are consistent secondary findings.

Dynamic ultrasound with real-time Thompson maneuver is highly accurate (>90% sensitivity) for complete ruptures and is lower cost and immediately available. However, MRI surpasses ultrasound in characterising partial tears, quantifying tendon substance involvement, assessing insertional enthesopathy, and evaluating concurrent retrocalcaneal bursitis or paratenon inflammation. MRI is preferred pre-operatively and in cases where ultrasound findings are equivocal, particularly for mid-substance versus insertional tear distinction critical to surgical approach.

AI models trained on follow-up Achilles MRI datasets can quantify tendon cross-sectional area, intratendinous T2 signal ratio, and fibrillar architecture restoration on high-resolution sequences. These metrics correlate with biomechanical tendon properties better than symptom scores alone. Persistent hyperintensity on T2-FS at 6 months despite clinical recovery signals incomplete structural healing, informing extended rehabilitation timelines and reducing re-rupture risk before return to loading sport.