Assessment of proximal tibial fractures with 3D FRACTURE (fast field echo resembling a CT using restricted echo-spacing) MRI-intra-individual comparison with CT.

Objectives: To evaluate the feasibility and diagnostic performance of a 3D FRACTURE (fast field echo resembling a CT using restricted echo-spacing) MRI sequence for the detection and classification of proximal tibial fractures compared with CT.

Methods: We retrospectively included 126 patients (85 male; 39.6 ± 14.5 years) from two centers following acute knee injury. Patients underwent knee MRI at 3 T including FRACTURE-MRI. Additional CT was performed in patients with tibial fractures (32.5%; n = 41) as the reference standard for fracture classification. Two radiologists independently evaluated FRACTURE-MRI for the presence of fractures and classified them according to AO/OTA, Schatzker, and the 10-segment classification. Diagnostic performance of FRACTURE-MRI was assessed using crosstabulations. Inter-reader agreement was estimated using Krippendorff's alpha. Image quality was graded on a five-point scale (5 = excellent; 1 = inadequate definition of fracture lines and fracture displacement) and assessed using estimated marginal means.

Results: Fractures were detected by FRACTURE-MRI with a sensitivity of 91.5% (83.2-96.5%) and a specificity of 97.1% (93.3-99.0%). Regarding fracture classification, diagnostic performances were slightly lower, with the 10-segment classification yielding the best sensitivity of 85.7% (81.4-89.3%) and specificity of 97.4% (96.6-98.0%), and the Schatzker classification yielding the lowest sensitivity of 78.2% (67.4-86.8%) and specificity of 97.7% (94.1-99.4%). Inter-reader agreement across the whole cohort was excellent (Krippendorff's alpha 0.89-0.96) and when considering only patients with fractures, good to acceptable (0.48-0.91). Image quality was rated good (estimated marginal mean 4.3 (4.1-4.4)).

Conclusion: FRACTURE-MRI is feasible at 3 T enabling accurate delineation of fracture lines for precise diagnosis and classification of proximal tibial fractures.

Key points: Question CT-like MRI is increasingly being evaluated for its advantages in bone imaging but is not yet established in routine practice. Findings The 3D FRACTURE (fast field echo resembling a CT using restricted echo-spacing) MRI sequence is feasible at 3 T, allowing for diagnosis and classification of proximal tibial fractures. Clinical relevance FRACTURE-MRI might be a helpful alternative to computed tomography in an acute trauma setting by reducing costs and radiation exposure in patients requiring a preoperative MRI anyway.