Advanced MRI Technology in Safety & Intervention

先进的 MRI 安全技术

• 批准号: 7886510
• 负责人: PAUL A BOTTOMLEY
• 金额: $ 53.63万
• 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/7886510
• 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; National Institute of Biomedical Imaging and Bioengineering; Noise; Performance; Phase; Physiologic pulse; Published Comment; RF coil; Radiometry; Relative (related person); Reporting; Research; Research Ethics Committees; 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; public health relevance; 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 MRI“技术开发”补助金 (R01 RR15396) 由 NCRR 作为生物工程研究补助金资助，该角色现已转移到 NIBIB。首期资助推进了当时多通道高速MRI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；条状探测器的发明；和测温，在 1.5 特斯拉 (1.5T) 下实现速度和性能的数量级提升。与此同时，临床 3T MRI 扫描仪已经到来，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定的核心安全问题，以及 3T 内部探测器的安全性和潜在性能增益。这些是为动脉粥样硬化高分辨率成像的应用而开发的。特别是，我们提供了新的初步体内和体外实验和理论数据，表明信噪比 (SNR) 几乎翻了两番，3T 下视场 (FOV) 面积增加了约 10 倍，血管壁分辨率为 80-1505m。虽然 3T 提供更高的 SNR，但 MRI 期间沉积的射频功率、比吸收率（SAR，W/kg）从 1.5T 到​​ 3T 增加了四倍，而其他条件相同，这引发了真正的安全问题，从根本上限制了 3T 扫描仪的操作。然而，目前还没有独立的方法来测量 MRI 期间的 SAR，以确保在评估新的 MRI 技术、调查 MRI 引起的射频烧伤、建立可靠的 SAR 水平以评估设备安全性或由医学物理学家进行常规 MRI 质量评估时遵守 FDA 和/或 IRB 指南。目标 1 解决了核心安全问题，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 以及设备测试。 Aim 2 开发了新型高信噪比内部探测器，解决了 3T 时加热增加和去耦问题，并将该技术应用于动脉粥样硬化动物模型。 Aim 3 将其扩展到一种新的 MRI 方法，该方法本质上锁定到内部探测器，从而创建真正的 MRI 内窥镜。随着探头的前进，内窥镜直接从探头的角度提供显微成像，避免了使用扫描仪询问探头位置的低效率。它还在动脉粥样硬化模型上进行了测试。目标 4 回到剂量测定，将我们的测温工作扩展到 3T 下内部金属探测器射频加热的更高潜力，使用探测器本身作为独立的射频辐射计。这些生物工程的进步将广泛惠及使用 MRI 的多个 NIH 机构，并为这一关键模式的安全做出重要贡献。公共健康相关性：这项拨款提供了新技术，用于独立评估 MRI 中的射频功率沉积，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 内窥镜检查带来巨大的灵敏度和分辨率增益，并有望应用于血管疾病和易损斑块的评估和治疗。