Acceleration of slice encoding for metal artifact correction at 0. 55 T using hexagonal sampling

作者：Bahadır Alp Barlas, Kübra Keskin, Bochao Li, Brian A. Hargreaves, Krishna S. Nayak · 发表于：Magnetic Resonance in Medicine · 年份：2025 · DOI：10.1002/mrm.70077 · 被引用次数：3 · 研究领域：Advanced X-ray and CT Imaging、Advanced X-ray Imaging Techniques、Medical Imaging Techniques and Applications

PURPOSE: To evaluate a hexagonal sampling approach for accelerated slice encoding for metal artifact correction (SEMAC) at 0.55 T. Contemporary mid-field systems (0.1 T-1.0 T) show tremendous potential for imaging near metal implants. However, the limited parallel-imaging options necessitate alternative methods for scan time reduction. METHODS: We apply retrospective hexagonal undersampling to current state-of-the-art SEMAC with 2-fold generalized autocalibrating partially parallel acquisitions-based parallel imaging at 0.55 T. The hexagonal sampling approach results in an additional 50% scan time reduction. Feasibility is evaluated with phantom experiments involving spinal fixation and total hip arthroplasty hardware, and in vivo experiments involving patients with spinal fusions with varying compositions and 1 volunteer with a total hip arthroplasty. RESULTS: Hexagonal sampling provides an additional 50% scan time reduction with compatible image quality. The two tradeoffs are (i) a small increase in signal void due to the loss of signal from one SEMAC spectral bin during post-acquisition filtering and (ii) position-dependent signal-to-noise-ratio reduction at locations close to the edge of the field of view in the phase-encoding direction. CONCLUSION: We demonstrate that hexagonal sampling can provide 50% scan time reduction in addition to generalized autocalibrating partially parallel acquisitions/parallel imaging for SEMAC at 0.55 T without introducing substantial artifac...