腹部および心臓MRI撮像におけるモーションミティゲーション技術

MRI of the heart and abdominal organs provides unparalleled soft tissue contrast and quantitative biomarkers, yet remains highly susceptible to physiological motion. Contractions of the myocardium, respiratory excursions, peristalsis, vascular pulsatility, and unpredictable bulk patient movement generate artifacts that impair image quality, limit reproducibility, and may necessitate repeat scans. This review summarizes motion correction strategies in cardiac and abdominal MRI, emphasizing both clinical applications and methodological principles. Techniques to address motion can be broadly categorized into prospective and retrospective approaches. Prospective methods adjust acquisition in real time, for example through respiratory or cardiac gating, navigator echoes, or external sensors, while retrospective strategies apply corrections during or after reconstruction, using k-space binning, image registration, or model-based reconstructions. Rigid motion, such as translations or rotations of organs, can often be corrected efficiently, whereas non-rigid motion including myocardial contraction or peristalsis requires more sophisticated elastic registration or motion-compensated reconstruction. Application-specific challenges and solutions are highlighted across cardiac cine imaging, flow quantification, tagging, and quantitative mapping, as well as abdominal imaging of the liver, kidneys, and gastrointestinal tract. In each domain, examples are provided of how motion impacts diagnostic performance and how motion correction strategies can mitigate these effects. Strengths and limitations of current approaches are reviewed, from conventional breath-holding to advanced free-breathing motion-resolved imaging. Emerging trends include integration of artificial intelligence with motion-compensated reconstruction, advanced sensor technologies for real-time tracking, and hybrid approaches combining multiple strategies. While many methods remain research-focused, vendor-embedded solutions and open-source tools are increasingly available, narrowing the gap between technical advances and routine practice. Motion correction is poised to become a core feature of clinical MRI, enabling faster, more robust, and patient-friendly examinations that reduce repeat rates, improve diagnostic confidence, and expand access to high-quality imaging in challenging patient populations. EVIDENCE LEVEL: N/A. TECHNICAL EFFICACY: Stage 5.