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。此外，运动校正一直集中在特定的序列家族上，但目前还没有普遍适用的方法。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。目标-我们将专注于三个独立的具体目标(并行执行并在4年内完成)，以及相应的子目标，我们认为这些子目标对于确立技术/科学优势并证明我们的实时自适应运动矫正方法拟议研发工作的可行性是重要的。具体地说，这些目标是：(1)开发和评估常规临床使用的线圈安装的MR兼容跟踪设备；(2)将姿势跟踪集成到实时MRI中；以及(3)在志愿者和患者身上验证我们的实时运动校正系统。方法-在目标1中，我们将改进磁共振扫描仪中基于计算机视觉的位姿估计方法，并建立可用于临床常规检查的与MR兼容的线圈安装位姿跟踪器。在目标2中，我们将专注于减少姿势变化发生和MR扫描仪对这些姿势变化做出反应之间的延迟，并构建用于MR脉冲序列开发的软件库，使人们能够对所有MR脉冲序列实施实时运动校正。在目标3中，我们将对60名志愿者(30名成人和30名儿童)和120名患者(80名成人和40名儿童)进行彻底的系统评估。意义-我们的技术的影响有几个方面。首先，它将通过减少由于运动伪影而导致质量下降的MR图像的数量来改善患者护理。特别是由于越来越依赖磁共振图像作为主要的诊断手段，这将减少误诊的数量。其次，这项技术将通过显著提高核磁共振扫描仪的效率，帮助降低国家在成像方面的高昂支出。最后，它将通过减少重复序列的需要来改善患者的舒适度，以及减少旨在保持患者静止的镇静的必要性。总体而言，这项技术将对MRI在临床实践和基础科学研究方面产生重大影响。 与公共卫生相关：在每年进行的4000万次核磁共振检查中，患者在检查过程中的动作可能会导致图像质量的严重下降和效率的降低。这不仅由于人口老龄化及其相关疾病而日益令人担忧，而且在儿童和患者中也是如此，他们在检查时病得无法保持静止。这项提议旨在建立一种光学跟踪系统和方法，以使MRI脉冲序列实时适应患者姿势的变化。该项目利用了R21项目之前的工作，在该项目中，成功地构建了原型系统。具体地说，目的是(I)对现有原型进行创新改进，使该系统适合于临床常规使用，(Ii)修改光学跟踪系统，使其与多个MR序列兼容，以及(Iii)进行临床评估。我们的实时技术是一种独特的创新解决方案，将改善MRI图像质量，从而改善患者护理，并将解决医疗保健系统不断上升的成像成本负担。

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. Moreover, motion correction has been focused on specific families of sequences, but no generally applicable approach currently exists. 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 - We will be focusing on three independent specific aims (carried out in parallel and completed within 4 years), with corresponding subaims that we believe are important for establishing the technical/scientific merit and to demonstrate the feasibility of the proposed R&D efforts for our real-time adaptive motion correction approach. Specifically, these aims are: (1) to develop and evaluate a coil-mounted MR-compatible tracking device for routine clinical use; (2) to integrate pose tracking into real-time MRI; and (3) to validate our real-time motion correction system in volunteers and patients. METHODS -In Aim 1 we will improve the methods for computer-vision-based pose estimation inside an MR scanner and build an MR-compatible coil-mounted pose tracker that can be used in clinical routine examinations. In Aim 2 we will focus on reducing the latency between pose changes happening and the MR scanner reacting to these pose changes, and on building a software library for the MR pulse sequence development that allows one to implement real-time motion correction into all MR pulse sequences. In Aim 3 we will perform a thorough evaluation of our system on 60 volunteers (30 adults and 30 children) and 120 patients (80 adults and 40 children). SIGNIFICANCE - The impact of our technology has several facets. First, it will improve patient care by reducing the number of MR images with compromised quality because of motion artifacts. Especially because of the increasing reliance on MR Images as a primary means of diagnosis, this will reduce the number of misdiagnoses. Secondly, this technology will help to lower the high national spending on imaging by dramatically improving the efficiency of MRI scanners. Finally, it will improve patient comfort by reducing the need for repeat sequences, as well as reduce the necessity of sedation aimed at keeping the patient still. Overall, this technology will have a significant impact on MRI both in clinical practice and basic science research. PUBLIC HEALTH RELEVANCE: Synopsis Patient motion during an MRI exam can result in major degradation of image quality and decreased efficiency in a large portion of the 40 million MRI procedures performed annually. This is not only of increasing concern due to the aging population and its associated diseases, but also in children and patients who are simply too sick to remain still during an exam. This proposal aims to build an optical tracking system and methods to adapt MRI pulse sequences to changes in patient pose in real time. The project leverages on previous work from an R21 project in which a prototype system was successfully built. Specifically, the aims are to (i) introduce innovative improvements to the existing prototype, making the system suitable for use in clinical routine, (ii) modify the optical tracking system to be compatible with multiple MR sequences, and (iii) perform clinical evaluation. Our real-time technique is a unique and innovative solution that will improve MRI image quality and thus patient care, and will address the escalating burden of imaging costs on the health care system.