RGR-based motion tracking for real-time adaptive MR imaging and spectroscopy

说明(申请人提供)：本申请是对2005年5月首次提交的1R01 DA21146-01的修订申请。磁共振成像(MRI)和波谱(MRS)是在活体内评估人脑结构和化学或代谢的强大技术。这些技术提供了相对较高的空间和时间分辨率，是非侵入性的和可重复的，可以在儿童身上进行。然而，在许多MR研究中，运动仍然是一个严重的问题，特别是那些在儿童、婴儿或因焦虑、药物使用或疾病而焦虑或困惑的受试者身上进行的研究，导致数据中存在运动伪影，这可能会阻碍准确的诊断或评估。因此，BRP的主要技术目标是开发(1)高精度和健壮的光学头跟踪系统，潜在的时间分辨率在毫秒范围内，以及(2)用于跟踪系统的实时自适应MRS和MRS技术。该跟踪系统将利用最近开发的“回光反射器”，即RGR，允许用一个记号笔和一个相机精确测量完整的姿势。同时，我们将开发MRI和MRS脉冲序列，允许在单个采集内进行运动校正，时间分辨率为10ms。最终的自适应运动校正系统和序列将在三个容易运动的目标人群中得到广泛验证：1)在宫内接触甲基苯丙胺的儿童(3-7岁)，2)因过度运动而需要重复进行核磁共振扫描的住院患者，以及3)头部震颤的患者。我们组建了一支经验丰富的调查小组，他们都是各自领域的专家。该项目的PI是Thomas Ernst(夏威夷大学)，他是一名MR物理学家，将协调整个项目并开发MRI和夫人的实时运动校正技术。其他牵头研究人员是：Brian S.R.Armstrong博士(威斯康星大学密尔沃基分校)将开发一种基于RGR的实时运动跟踪系统。Thomas Prieto博士(威斯康星医学院)将负责跟踪和校准系统的整体工程，特别是在核磁共振扫描仪的范围内。奥利弗·斯派克博士(德国弗莱堡大学)将负责开发具有扫描内运动校正功能的MRI序列。斯派克博士的团队还开发了一个独特的软件包，允许从外部设备实时控制MRI扫描。西门子医疗解决方案公司的Gerhard Laub博士同意担任该项目的技术顾问。最后，人类主体活动，特别是系统的最终验证，将由一个有四名医生成员的医学咨询委员会指导。

DESCRIPTION (provided by applicant): This is a revised application for 1R01 DA21146-01, which was originally submitted in May, 2005. Magnetic resonance imaging (MRI) and spectroscopy (MRS) are powerful techniques for assessing structure and chemistry or metabolism of the human brain in vivo. These techniques afford relatively high spatial and temporal resolution, are non-invasive and repeatable, and may be performed in children. However, motion continues to be a substantial problem in many MR studies, especially those performed in children, infants, or subjects who are agitated or confused due to anxiety, drug use or sickness, resulting in data with motion artifacts that could prevent accurate diagnoses or assessments. Therefore, the overarching technical goals of this BRP are to develop (1) an optical head tracking system that is highly accurate and robust, with a potential time resolution in the millisecond range, and (2) real-time adaptive MRS and MRS techniques for use with the tracking system. The tracking system will utilize recently-developed "retrograte reflectors", or RGRs, that allow accurate measurement of full pose with a single marker and a single camera. In parallel, we will develop MRI and MRS pulse sequences that allow motion correction WITHIN single acquisitions, at a time resolution of 10ms. The final adaptive motion correction system and sequences will be validated extensively in three target populations that are prone to motion: 1) children (3-7 years old) who were exposed to methamphetamine in utero, 2) hospitalized in- patients who require repeat MRI scans due to excessive motion, and 3) patients with head tremors. We have assembled a team of experienced investigators who are experts in their respective areas. The PI of the project is Thomas Ernst (University of Hawaii), an MR physicist who will coordinate the overall project and develop techniques for real-time motion correction in MRI and MRS. Other lead investigators are: Brian S.R. Armstrong, Ph.D., (University of Wisconsin in Milwaukee) will develop a real-time, RGR-based motion tracking system. Thomas Prieto, Ph.D. (Medical College of Wisconsin) will be responsible for the overall engineering of the tracking and calibration system specifically within the confines of an MRI scanner. Oliver Speck, Ph.D. (University of Freiburg, Germany), will be responsible for developing MRI sequences with within-scan motion correction. Dr. Speck's group also developed a unique software package that allows real-time control of MRI scans from external devices Dr. Gerhard Laub from Siemens Medical Solutions agreed to be a Technical Advisor to the project. Finally, human subject activities, especially the final validation of the system, will be guided by a Medical Advisory Board with four physician members.