Online MRI Positioning and Real-Time Motion Correction

在线 MRI 定位和实时运动校正

• 批准号: 6734280
• 负责人: Andre Jan Willem van der Kouwe
• 金额: $ 25.51万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-15 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6734280
• 关键词: bioimaging /biomedical imaging; brain; clinical research; human subject; magnetic resonance imaging; method development; neuroimaging

DESCRIPTION (provided by applicant): Automatic on-line slice positioning, on-line slice position correction and prospective real-time motion correction for magnetic resonance imaging of the human brain will be implemented. These technologies will improve the work-flow efficiency of routine clinical evaluations of the brain, and ensure accurate reproducibility of slice positioning over several scanning sessions for the evaluation of progressive illnesses such as tumors and multiple sclerosis. Motion correction will extend the usefulness of MR imaging to traditionally troublesome populations such as children, older subjects and subjects with movement disorders such as Parkinson's disease, where head movements in the scanner frequently preclude successful scanning and confound an accurate diagnosis. Automatic slice positioning obviates the need for the technologist to manually prescribe slices, thereby saving time and improving the reproducibility of scans between scanners, technologists and between sessions in longitudinal studies. The technology is based on a segmented averaged probabilistic atlas and uses a rapid gradient echo (GRE) localizer sequence with two acquisitions with differing contrasts to provide a rapid method for reliably discriminating between the various tissues in the human head and brain. The localizer is collected in approximately forty seconds at the beginning of the scanning session, and to correct for subsequent motion of the subject, two second echo-planar or segmented GRE correction localizers are interleaved between scans. These are referenced to an initial rapid correction localizer to ensure consistent positioning of every scan in the session. Test-retest reliability will be evaluated in a group of healthy volunteers. To correct for within-scan motion, a prospective real-time motion correction scheme is proposed. The scheme requires embedded "octant" navigators of less than 3 ms interleaved between the lines of a conventional 3D sequence such as GRE or 3D EPI. By comparing the navigators with an initial rapidly acquired map of k-space in the vicinity of the navigators, a full rigid body assessment can be made of the position of the object in the scanner at a rate of 50 Hz or more. Corrections to the images can be done off-line, or are made on the scanner in real-time using the rapid feedback mechanism that the Siemens platform provides. The technology will be evaluated in a group of healthy volunteers.

描述（由申请人提供）： 将实施自动在线切片定位，在线切片位置校正和前瞻性实时运动校正，以实现人脑的磁共振成像。这些技术将提高大脑常规临床评估的工作流效率，并确保在几个扫描过程中切片定位的准确可重复性，以评估肿瘤和多发性硬化症等进行性疾病。运动校正将把MR成像的有用性扩展到传统上麻烦的人群，例如儿童，老年受试者和运动障碍的受试者，例如帕金森氏病，扫描仪中的头部运动经常排除成功的扫描并混淆了准确的诊断。自动切片定位避免了技术专家手动开处方切片的需求，从而节省了时间，并提高了扫描仪，技术人员和纵向研究中的会议之间的扫描的可重复性。该技术基于一个分段的平均概率地图集，并使用具有两种不同对比度的两次采集，使用了快速的梯度回声（GRE）定位序列，以提供可靠地区分人头和大脑中各种组织的快速方法。在扫描会议开始时，在大约40秒内收集了定位器，为了纠正受试者的后续运动，在扫描之间交织了两个第二个回声平面或分段的GRE校正局部化器。这些引用了初始快速校正本地化机构，以确保会话中每次扫描的一致定位。重测可靠性将在一组健康的志愿者中进行评估。为了纠正扫描内运动，提出了前瞻性的实时运动校正方案。该方案需要在常规3D序列（例如GRE或3D EPI）线之间交错的嵌入少于3 ms的“八合一导航器”。通过将导航器与导航器附近的最初迅速获得的K空间图进行比较，可以以50 Hz或以上的速率对物体的位置进行完整的刚体评估。可以使用Siemens平台提供的快速反馈机制在扫描仪上进行校正，也可以在扫描仪上实时进行。该技术将在一组健康的志愿者中进行评估。