Abstract：
T1-weighted (T1W) pulse sequences are an indispensable component of clinical protocols in abdominal MRI but usually require multiple breath holds (BHs) during the examination, which not all patients can sustain. Patient motion can affect the quality of T1W imaging so that key diagnostic information, such as intrinsic signal intensity and contrast enhancement image patterns, cannot be determined. Patient motion also has a negative impact on examination efficiency, as multiple acquisition attempts prolong the duration of the examination and often remain noncontributory. Techniques for mitigation of motion-related artifacts at T1W imaging include multiple arterial acquisitions within one BH; free breathing with respiratory gating or respiratory triggering; and radial imaging acquisition techniques, such as golden-angle radial k-space acquisition (stack-of-stars). While each of these techniques has inherent strengths and limitations, the selection of a specific motion-mitigation technique is based on several factors, including the clinical task under investigation, downstream technical ramifications, patient condition, and user preference. The authors review the technical principles of free-breathing motion mitigation techniques in abdominal MRI with T1W sequences, offer an overview of the established clinical applications, and outline the existing limitations of these techniques. In addition, practical guidance for abdominal MRI protocol strategies commonly encountered in clinical scenarios involving patients with limited BH abilities is rendered. Future prospects of free-breathing T1W imaging in abdominal MRI are also discussed. ©RSNA, 2024 See the invited commentary by Fraum and An in this issue.
摘要：
T1加权（T1W）脉冲序列是腹部MRI临床方案中不可或缺的组成部分，但通常在检查过程中需要多次屏气（BHs）。并非所有患者都能维持。患者运动会影响T1W成像的质量，从而使关键诊断信息，如本征信号强度和对比度增强图像模式，无法确定。患者的运动对检查效率也有负面影响，由于多次获取尝试会延长检查的持续时间，并且通常保持无贡献。用于减轻T1W成像时的运动相关伪影的技术包括在一个BH内的多个动脉采集;具有呼吸门控或呼吸触发的自由呼吸;和径向成像采集技术，例如金角径向k空间采集(星堆)。虽然这些技术都有固有的优势和局限性，特定运动缓解技术的选择基于几个因素，包括正在调查的临床任务，下游技术后果，患者状况,和用户偏好。作者回顾了T1W序列腹部MRI中自由呼吸运动缓解技术的技术原理，提供已建立的临床应用的概述，并概述了这些技术的现有局限性。此外,针对BH能力有限的患者在临床情况下常见的腹部MRI方案策略提供了实践指导.还讨论了自由呼吸T1W成像在腹部MRI中的未来前景。©RSNA,2024请参见本期Fraum和An的特邀评论。
