Advanced MRI Technology in Safety & Intervention

先进的 MRI 安全技术

• 批准号: 7578096
• 负责人: PAUL A BOTTOMLEY
• 金额: $ 53.15万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-30 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7578096
• 关键词: Address; Animal Model; Animals; Area; Arterial Fatty Streak; Atherosclerosis; Back; Behavior; Biomedical Engineering; Blood Vessels; Burn injury; Cephalometry; Clinical; Data; Deposition; Device Safety; Devices; Endoscopes; Endoscopy; Engineering; Ensure; Eye; Feasibility Studies; Feedback; Frequencies; Funding; Grant; Guidelines; Head; Heating; Human; Image; Imaging Techniques; Imaging technology; In Vitro; Injury; Institutes; Intervention; Investigation; Laboratories; Location; Magnetic Resonance Imaging; Measurement; Measures; Medical; Methods; Modality; Modeling; Monitor; National Center for Research Resources; Noise; Operative Surgical Procedures; Performance; Phase; Physiologic pulse; Public Health; Published Comment; Pulse taking; RF coil; Radiometry; Rate; Relative (related person); Reporting; Research; Research Ethics Committees; Research Personnel; Research Project Grants; Resolution; Role; Route; Safety; Sampling; Signal Transduction; Speed; Standards of Weights and Measures; Surface; System; Technology; Temperature; Testing; Thermometry; Time; Tissues; Transducers; Translating; United States Food and Drug Administration; United States National Institutes of Health; Vascular Diseases; Work; absorption; clinical application; design; design and construction; detector; dosimetry; imaging detector; imaging probe; implantable device; improved; in vivo; in vivo Model; magnetic field; new technology; novel; patient safety; programs; prototype; size; technology development; tool; voltage

DESCRIPTION (provided by applicant): This MRI "technology development" grant (R01 RR15396) was funded by the NCRR as a Bioengineering Research grant, a role now shifted to NIBIB. The initial grant advanced the then new technologies of multi- channel high-speed MRI, including the first clinical 32-channel parallel MRI; local gradients with ~10-fold increases in strength and speed; optimized signal-to-noise ratio (SNR) detectors; the invention of strip detectors; and thermometry, achieving order-of-magnitude gains in speed and performance at 1.5 Tesla (1.5T). Meanwhile, clinical 3T MRI scanners have arrived, and this more-focused renewal request, extends thermometry and detector optimization to address core safety issues of RF heating and dosimetry, and the safety and potential performance gains of internal detectors at 3T. These are developed for applications to high-resolution imaging in atherosclerosis. In particular, we provide new preliminary in vivo and in vitro experimental and theoretical data suggesting a nearly quadrupling of signal-to-noise ratio (SNR), a ~10-fold gain in field-of-view (FOV) area at 3T, and 80-1505m resolution of vessel walls. While 3T delivers higher SNR, the RF power deposited during MRI, the specific absorption rate (SAR, W/kg), quadruples from 1.5T to 3T, all else being the same, raising genuine safety concerns that fundamentally limit 3T scanner operation. Yet, there are currently no independent means of measuring SAR during MRI for ensuring compliance with FDA and/or IRB guidelines when evaluating new MRI techniques, investigating RF burns caused by MRI, establishing reliable SAR levels for assessing device safety, or for routine MRI quality assessment by Medical Physicists. The central safety issue is addressed in Aim 1 which develops the first SAR dosimeter for clinical head and body MRI and applies it to assessing scanner SAR following burn reports, and to device testing. Aim 2 develops new high-SNR internal detectors, solving the increased heating and decoupling problems at 3T, and applying the technology to an animal model of atherosclerosis. Aim 3 extends this to a new MRI method that is inherently locked to the internal detector, creating a true MRI endoscope. The endoscope provides micro- imaging directly from the view-point of the probe as it is advanced, avoiding the inefficiencies of interrogating probe location with the scanner. It is also tested on the atherosclerosis model. Aim 4 returns to dosimetry, extending our thermometry work to the much higher potential for RF heating of internal metallic detectors at 3T, using the detector itself as an independent RF radiometer. These bio-engineering advances will broadly benefit the multiple NIH institutes that utilize MRI, and contribute importantly to the safety of this key modality. PUBLIC HEALTH RELEVANCE: This grant provides novel technology for independently assessing RF power deposition in MRI for monitoring its safe operation, and for evaluating the safety of implanted devices. It will provide new internal MRI probes that promise large sensitivity and resolution gains for local high-resolution imaging and MRI endoscopy, with potential applications to the assessment and treatment of vascular disease and vulnerable plaque.

描述（由申请人提供）：该MRI“技术开发”补助金（R 01 RR 15396）由NCRR资助，作为生物工程研究补助金，现在的作用转移到NIBIB。最初的拨款推动了当时多通道高速MRI的新技术，包括第一个临床32通道并行MRI;强度和速度增加约10倍的局部梯度;优化的信噪比（SNR）探测器;条带探测器的发明;以及温度测量，在1.5特斯拉（1.5T）下实现了速度和性能的数量级增益。与此同时，临床3 T MRI扫描仪已经上市，这一更有针对性的更新请求扩展了温度测量和探测器优化，以解决射频加热和剂量测定的核心安全问题，以及内部探测器在3 T下的安全性和潜在性能增益。这些被开发用于动脉粥样硬化的高分辨率成像。特别是，我们提供了新的初步的体内和体外实验和理论数据，表明信号噪声比（SNR）的近四倍，在3 T的视场（FOV）面积约10倍的增益，和80- 1505米的血管壁的分辨率。虽然3 T提供了更高的SNR，但MRI期间沉积的RF功率，比吸收率（SAR，W/kg），从1.5T到3 T增加了四倍，所有其他都是相同的，这引起了真正的安全问题，从根本上限制了3 T扫描仪的操作。然而，在评价新的MRI技术、研究MRI引起的RF灼伤、建立可靠的SAR水平以评估器械安全性或由医学物理学家进行常规MRI质量评估时，目前没有独立的方法在MRI期间测量SAR，以确保符合FDA和/或IRB指南。在目标1中解决了中心安全性问题，该目标开发了第一个用于临床头部和身体MRI的SAR剂量计，并将其应用于评估烧伤报告后的扫描仪SAR和器械测试。目的2开发新的高信噪比内部探测器，解决在3 T下增加的加热和去耦问题，并将该技术应用于动脉粥样硬化的动物模型。目标3将其扩展到一种新的MRI方法，该方法固有地锁定到内部探测器，从而创建真正的MRI内窥镜。内窥镜在探头前进时直接从探头的视点提供显微成像，避免了用扫描仪询问探头位置的低效。还在动脉粥样硬化模型上进行了测试。目标4返回到剂量学，将我们的测温工作扩展到内部金属探测器在3 T下RF加热的更高潜力，使用探测器本身作为独立的RF辐射计。这些生物工程的进步将使使用MRI的多个NIH研究所广泛受益，并对这一关键模式的安全性做出重要贡献。公共卫生关系：该基金提供了新的技术，用于独立评估MRI中的射频功率沉积，以监测其安全运行，并评估植入器械的安全性。它将为局部高分辨率成像和MRI内窥镜检查提供新的内部MRI探头，有望获得较大的灵敏度和分辨率增益，并可能应用于血管疾病和易损斑块的评估和治疗。