Metal artifact reduction MRI of total ankle arthroplasty implants

Objectives: To assess high-bandwidth and compressed sensing-(CS)-SEMAC turbo spin echo (TSE) techniques for metal artifact reduction MRI of total ankle arthroplasty (TAA) implants. Methods: Following institutional approval and consent, 40 subjects with TAA implants underwent 1.5-T MRI prospectively. Evaluations included bone-implant interfaces, anatomical structures, abnormal findings and differential diagnoses before and after MRI. AUCs of P-P plots were used to determine superiority. Statistical differences were evaluated with McNemar and chi-square tests. P-values ≤ 0.05 were considered significant. Results: CS-SEMAC TSE was superior to high-bandwidth TSE in showing the bone-implant interfaces (AUC=0.917), periprosthetic bone, tendons and joint capsule (AUC=0.337–0.766), bone marrow oedema (43 % difference, p=0.041), interface osteolysis (63 %, p=0.015), tendinopathy (62 %, p=0.062), periprosthetic fractures (60 %, p=0.250), synovitis (43 %, p=0.250), as well as reader confidence for bone marrow oedema (p=<0.001), fracture (p=0.001), interface osteolysis (p=0.003), synovitis (p=0.027) and tendinopathy (p=0.034). The number of differential diagnoses in symptomatic subjects after the MRI with CS-SEMAC decreased from 3 (1–4) to 1 (1–2) (p<0.001). Conclusions: MRI of TAA implants with CS-SEMAC improves the diagnosis of interface osteolysis, periprosthetic bone marrow oedema, fractures and tendinopathy when compared to high-BW TSE, and has a positive effect on patient management. Key Points: • High-bandwidth TSE and compressed sensing SEMAC improve MRI of ankle arthroplasty implants.• Compressed sensing SEMAC improves bone-implant interfaces, periprosthetic bone, tendons and joint capsule visibility.• Compressed sensing SEMAC improves the diagnosis of osteolysis, tendinopathy, fractures and synovitis.• MRI decreases the number of clinical differential diagnoses of painful ankle arthroplasty implants.