Washington University School of Medicine, Department of Psychiatry, United States; Washington University School of Medicine, Mallinckrodt Institute of Radiology, United States.
Washington University School of Medicine, Department of Psychiatry, United States.
Neuroimage. 2018 May 1;171:234-245. doi: 10.1016/j.neuroimage.2018.01.023. Epub 2018 Jan 12.
A major limitation to structural and functional MRI (fMRI) scans is their susceptibility to head motion artifacts. Even submillimeter movements can systematically distort functional connectivity, morphometric, and diffusion imaging results. In patient care, sedation is often used to minimize head motion, but it incurs increased costs and risks. In research settings, sedation is typically not an ethical option. Therefore, safe methods that reduce head motion are critical for improving MRI quality, especially in high movement individuals such as children and neuropsychiatric patients. We investigated the effects of (1) viewing movies and (2) receiving real-time visual feedback about head movement in 24 children (5-15 years old). Children completed fMRI scans during which they viewed a fixation cross (i.e., rest) or a cartoon movie clip, and during some of the scans they also received real-time visual feedback about head motion. Head motion was significantly reduced during movie watching compared to rest and when receiving feedback compared to receiving no feedback. However, these results depended on age, such that the effects were largely driven by the younger children. Children older than 10 years showed no significant benefit. We also found that viewing movies significantly altered the functional connectivity of fMRI data, suggesting that fMRI scans during movies cannot be equated to standard resting-state fMRI scans. The implications of these results are twofold: (1) given the reduction in head motion with behavioral interventions, these methods should be tried first for all clinical and structural MRIs in lieu of sedation; and (2) for fMRI research scans, these methods can reduce head motion in certain groups, but investigators must keep in mind the effects on functional MRI data.
结构和功能磁共振成像（fMRI）扫描的一个主要限制是它们容易受到头部运动伪影的影响。即使是亚毫米级的运动也可以系统地扭曲功能连接、形态测量和扩散成像结果。在患者护理中，通常使用镇静来最小化头部运动，但这会增加成本和风险。在研究环境中，镇静通常不是一个伦理选择。因此，减少头部运动的安全方法对于提高 MRI 质量至关重要，特别是在高运动人群中，如儿童和神经精神患者。我们研究了以下两种方法对 24 名儿童（5-15 岁）的影响：（1）观看电影；（2）实时反馈头部运动情况。在 fMRI 扫描期间，孩子们观看固定十字（即休息）或卡通电影片段，并且在一些扫描中，他们还实时反馈头部运动情况。与休息相比，观看电影时头部运动明显减少，与不反馈相比，收到反馈时头部运动也明显减少。然而，这些结果取决于年龄，因此主要是由年龄较小的儿童驱动的。10 岁以上的儿童没有明显的获益。我们还发现，观看电影会显著改变 fMRI 数据的功能连接，这表明电影期间的 fMRI 扫描不能等同于标准的静息态 fMRI 扫描。这些结果的意义有两点：（1）鉴于行为干预可以减少头部运动，在所有临床和结构 MRI 中，这些方法都应该首先尝试，而不是使用镇静剂；（2）对于 fMRI 研究扫描，这些方法可以减少某些群体的头部运动，但研究人员必须记住这些方法对功能 MRI 数据的影响。
