Real-Time MRI Motion Correction System

描述(由申请人提供)：动机-在MR研究中，运动仍然是图像伪影最常见的贡献者之一。核磁共振的运动敏感性是众所周知的，并催生了许多优雅的导航技术。然而，这些方法是为特定的MR采集量身定做的，需要修改k空间轨迹或获取额外的MR数据，并且大多数方法不能校正某些类型的运动，例如通过平面的运动。某些患者群体，如儿科或老年病患者，比其他患者更有可能流动。在儿科成像中，麻醉被用来控制运动，这大大增加了检查成本和患者风险。一个独立于序列的、自主的和前瞻性的运动校正系统可以极大地提高广泛范围的MR检查的图像质量。特别是对于儿科成像，我们预计减少对麻醉控制患者运动的依赖。AIMS-该项目旨在探索使用另一种MRI运动补偿方法的可能性，使用患者位置的连续光学监控和准实时更新MR扫描仪的3D坐标系。因此，采集跟随患者头部的运动，提供几乎没有运动伪影和旋转历史伪影的MR扫描。这种方法将需要开发和校准与MR兼容的光学位置捕获系统(AIM 1)，该系统可用于持续更新扫描仪的参考坐标系(AIM 2)。最后，有必要在志愿者身上测试新系统，以评估与传统扫描或基于导航的方法相比在图像质量方面的改进(目标3)。方法：将开发一种与MR兼容的光学位置跟踪装置，并将其安装到普通磁头线圈上。该设备将MR系统的参照系锁定到由患者头部位置定义的参照系。因此，当患者发生运动时，MR系统将更新其射频激励、梯度和数据接收，以跟上此运动的步伐。在两年多的时间里，健康儿童(n=38)和成年人(n=22)将被招募来比较传统MR和运动补偿MR，同时受试者在四个预先定义的严重程度下进行运动。意义-该项目的成功将显著改善在有运动的情况下进行的MR检查，因此将使大多数患者受益。然而，我们预计，在儿科和老年患者中，使用运动补偿MR的优势将是最大的。这项研究的积极成果还将通过减少总体扫描时间或提高图像的诊断能力来间接影响患者。我们有信心在未来的研究中表明，通过使用我们的方法，在儿科扫描中对麻醉的依赖可以显著减少。磁共振成像继续开发新的方法来最小化或消除降低图像质量和增加患者检查时间的运动误差。该项目开发了一种基于光学运动检测系统的独特方法，该系统将安装在MRI磁头线圈上。光学系统将跟踪头部位置；在图像采集过程中纠正运动；提高诊断图像质量；减少甚至消除因患者头部运动而重复检查的需要。

DESCRIPTION (provided by applicant): MOTIVATION - Motion remains one of the most frequent contributors to image artifacts in MR studies. The motion susceptibility of MRI is well-known and has spawned a number of elegant navigation techniques. These methods, however, are tailored to specific MR acquisitions that require modified k-space trajectories or the acquisition of additional MR data, and most are unable to correct certain types of motion, for example, through-plane motion. Certain patient populations, such as pediatric or geriatric patients, are more likely to move than others. In pediatric imaging, anesthesia is used to control motion, adding substantially to exam costs and patient risks. A sequence-independent, autonomous and prospective motion correction system could greatly improve image quality for a wide spectrum of MR examinations. For pediatric imaging, in particular, we anticipate reduced reliance on anesthesia to control patient motion. AIMS - This project aims to explore the potential to use an alternative MRI motion compensation approach, using continuous optical monitoring of patient position and updating of the MR scanner's 3D coordinate system in quasi real-time. Acquisition thus follows the movement of the patients head, providing MR scans virtually free from motion artifacts and without spin history artifacts. This approach will require the development and calibration of an MR compatible optical position capture system (Aim 1), which can be used to continually update the scanner's reference coordinate system (Aim 2). Finally, testing the new system on volunteers is necessary to assess the improvements in image quality over conventional scanning or navigator- based methods (Aim 3). METHODS - An MR-compatible optical position tracking device will be developed and mounted to common head coils. This device will lock the MR system's frame of reference to that defined by the position of the patient's head. Therefore, when patient motion occurs, the MR system will update its RF excitation, gradients, and data reception to keep pace with this motion. Over 2 years, healthy children (n=38) and adults (n=22) will be enrolled to compare conventional MR and motion-compensated MR while subjects perform movements at four predefined levels of severity. SIGNIFICANCE - The success of this project will significantly improve MR exams conducted in the presence of motion and will therefore benefit most patient populations. However, we expect that in pediatric and geriatric patients the advantages from using motion-compensated MR will be greatest. A positive outcome of this research effort will also affect patients indirectly by reducing the overall scan time or improving diagnostic capacity of the images. We are confident to show in future studies that, by using our approach, the dependence upon anesthesia in pediatric scanning can be significantly reduced. MR imaging continues to develop new approaches to minimize or eliminate motion errors that decrease image quality and increase patient exam time. This project develops a unique approach based on an optical motion detecting system that will be mounted on an MRI head coil. The optical system will track head position; correct for motion throughout image acquisition time; result in improved diagnostic image quality; and reduce, or even eliminate, the need for repeat studies due to patient head motion.