Impact of sequence selection on postoperative MRI interpretability and artifact reduction in simulated mandibular trauma.

INTRODUCTION: This ex vivo study evaluated the diagnostic performance of different MRI sequences for postoperative imaging of simulated mandibular fractures stabilized with titanium and bioresorbable osteosynthesis materials. METHODS: Six porcine mandibles with standardized fractures of the mandibular angle, body, and parasymphysis were stabilized using titanium microplates, titanium reconstruction plates, or bioresorbable systems. All specimens underwent photon-counting computed tomography (CT) as a reference and 3 Tesla MRI, including five sequences: T1-weighted turbo spin echo (T1-TSE), DIXON-based imaging (DIXON), T1-TSE with vendor-specific artifact reduction techniques (WARP), ultrashort echo time (UTE), and slice encoding for metal artifact correction (SEMAC). Three blinded observers rated general image interpretability, fracture visibility, artifact extent, and soft- as well as hard-tissue interpretability using five-point Likert scales. Quantitative analysis included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and two-dimensional artifact measurements. RESULTS: Advanced artifact-reduction sequences outperformed conventional T1-TSE and DIXON (p < 0.001). UTE and WARP achieved the highest general image interpretability (median 5) and excellent fracture line visibility, alongside SEMAC. WARP provided the best soft-tissue interpretability (median 5), highest muscle SNR (median 207.9 vs. 74.4 for SEMAC and 51.9 for UTE; p ≤ 0.013), and highest CNR (median 184.8 vs. 59.6 for SEMAC and 23.5 for UTE; p ≤ 0.043), while UTE demonstrated superior hard-tissue SNR (median 30.0 vs. 13.2 for SEMAC; p < 0.001). SEMAC showed the greatest reduction in artifact extent (135% relative to CT vs. 209% for WARP and 220% for UTE; p ≤ 0.004). There was good inter-reader agreement (α = 0.76). CONCLUSION: Advanced MRI sequences, such as SEMAC, UTE and WARP, substantially improved postoperative image interpretability and reduced implant-related artifacts. A tailored MRI protocol may complement CT in selected postoperative scenarios.