Advanced MRI Technology in Safety & Intervention

先进的 MRI 安全技术

• 批准号: 8101079
• 负责人: PAUL A BOTTOMLEY
• 金额: $ 52.83万
• 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 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8101079
• 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; Health; Heating; Human; Image; Imaging Techniques; Imaging technology; In Vitro; Injury; Institutes; Institutional Review Boards; Intervention; Investigation; Laboratories; Location; Magnetic Resonance Imaging; Measurement; Measures; Medical; Methods; Modality; Modeling; Monitor; National Center for Research Resources; National Institute of Biomedical Imaging and Bioengineering; Noise; Performance; Phase; Physiologic pulse; Published Comment; RF coil; Radiometry; Relative (related person); Reporting; Research; Research Personnel; Research Project Grants; Resolution; Role; Route; Safety; Sampling; Signal Transduction; Speed; 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 modality; imaging probe; implantable device; improved; in vivo; in vivo Model; magnetic field; new technology; novel; operation; patient safety; programs; prototype; safety testing; 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)：这项核磁共振“技术开发”资助(R01 RR15396)是由NCRR作为生物工程研究资助，这一角色现在转移到NIBIB。最初的拨款推动了当时多通道高速磁共振成像新技术的发展，包括第一个临床32通道并行磁共振成像；强度和速度提高约10倍的局部梯度；优化的信噪比(SNR)检测器；条状检测器的发明；以及测温，在1.5特斯拉(1.5T)下实现了数量级的速度和性能提升。与此同时，临床3T磁共振扫描仪已经问世，这一更有针对性的更新请求扩展了测温和探测器优化，以解决射频加热和剂量测量的核心安全问题，以及3T时内部探测器的安全和潜在性能提升。它们是为动脉粥样硬化的高分辨率成像应用而开发的。特别是，我们提供了新的体内和体外初步实验和理论数据，表明信噪比(SNR)几乎翻了两番，在3T时视野(FOV)面积增加了~10倍，血管壁的分辨率达到80-1505M。虽然3T提供了更高的SNR，但在MRI过程中沉积的射频功率、比吸收率(SAR，W/kg)从1.5T增加到3T，翻了两番，其他一切都是一样的，这引发了真正的安全担忧，从根本上限制了3T扫描仪的操作。然而，目前还没有在MRI过程中测量SAR的独立手段，以确保在评估新的MRI技术时遵守FDA和/或IRB指南，调查MRI引起的射频烧伤，建立可靠的SAR水平来评估设备安全性，或供医学物理学家进行常规MRI质量评估。主要的安全问题在Aim 1中得到了解决，该公司开发了第一台用于临床头部和身体MRI的SAR剂量计，并将其应用于烧伤报告后的扫描仪SAR评估和设备测试。目的2开发新的高信噪比内部探测器，解决3T加热和去耦合的问题，并将该技术应用于动脉粥样硬化的动物模型。AIM 3将这一点扩展到一种新的MRI方法，该方法固有地锁定在内部探测器上，创造了一个真正的MRI内窥镜。内窥镜在其前进时直接从探头的角度提供显微成像，避免了用扫描仪询问探头位置的低效。它还在动脉粥样硬化模型上进行了测试。AIM 4返回到剂量学，将我们的测温工作扩展到3T下内部金属探测器的射频加热潜力要高得多的领域，使用探测器本身作为独立的射频辐射计。这些生物工程的进展将使使用核磁共振的多个NIH研究所广泛受益，并对这一关键方法的安全性做出重要贡献。公共卫生相关性：这项赠款提供了新的技术，用于独立评估MRI中的射频能量沉积，以监测其安全操作，并评估植入设备的安全性。它将提供新的内部MRI探头，有望为局部高分辨率成像和MRI内窥镜提供更高的灵敏度和分辨率，在评估和治疗血管疾病和易损斑块方面具有潜在的应用。