Acousto-optical RF field sensors for safer diagnostic and interventional MRI

用于更安全的诊断和介入 MRI 的声光射频场传感器

• 批准号: 10093044
• 负责人: F. Levent Degertekin
• 金额: $ 41.57万
• 依托单位: GEORGIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10093044
• 关键词: Adverse event; Animal Model; Biopsy; Blood Flow Velocity; Cardiovascular system; Catheters; Chemicals; Clinic; Clinical; Complex; Coupled; Coupling; Deposition; Development; Devices; Diagnostic; Diffusion; Electromagnetics; Electronics; Elements; Engineering; Evaluation; Fiber; Film; Frequencies; Geometry; Goals; Heating; Image; Imaging Device; Imaging Techniques; Implant; Intervention; Investigation; Magnetic Resonance Imaging; Measurement; Measures; Mechanics; Microfabrication; Modeling; Optics; Outcome; Patient imaging; Patients; Performance; Perfusion; Pharmaceutical Preparations; Population; Positioning Attribute; Procedures; Radiation; Regulation; Research; Safety; Scanning; Signal Transduction; System; Systems Integration; Techniques; Temperature; Temperature Sense; Testing; Thinness; Time; Tissues; Transducers; Ultrasonic Transducer; United States National Institutes of Health; Universities; absorption; base; clinical practice; design; dosimetry; flexibility; heat injury; imaging biomarker; imaging modality; imaging system; improved; in vivo; individual patient; magnetic field; medical implant; novel; novel strategies; optical fiber; optical sensor; patient population; prevent; prototype; radio frequency; sensor; simulation; soft tissue; success; transmission process

Although adverse events related to MRI are rare, safety concerns due to RF induced heating have a significant impact in clinical use especially for a growing number of patients with medical implants. Current regulations based on estimated whole body absorption rate (SAR) impose unnecessary restrictions on RF power levels, sometimes reducing the diagnostic efficacy, while even these low levels can create safety issues for specific patients. Miniature sensors with local E-field and temperature measurement capability on individual patients during the scans can alleviate these limitations while improving safety. These sensors can also have an impact on interventional MRI applications where active markers, essentially miniature coils that locally measure the RF signal, provide the best device visibility. These markers, however suffer from RF induced heating over conductive transmission lines, an issue that gets exacerbated in higher field MR systems and does not currently have a solution that satisfies all mechanical and electrical constraints. We recently developed a miniature acousto- optical (AO) RF field sensor which detects and transmits the RF signal over an optical fiber instead of conductive transmission lines, and therefore is totally free of RF induced heating and electromagnetic interference. The same device has the potential to measure temperature as well as the local E/H field for SAR evaluation when coupled with a properly designed antenna. In this application, we aim to optimize the design of the AO sensor using unique mechanical resonances of optical fibers at Larmor frequencies of 0.55T, 1.5T and 3T systems and use microfabrication techniques to make device with thin film piezoelectric transducers. We also propose a novel packaging strategy to embed these AO RF field sensors in sleeves that can conform to any commercially available MRI compatible catheter, to significantly increase the device options for interventional MRI. These active markers and multi-parameter E/H field sensors will be rigorously tested according to the latest MRI safety standards and evaluated in vivo for several challenging cardiovascular interventional MRI procedures. Successful demonstration of the AO sensor as an active MRI marker with a non-conducting transmission line will be a significant development for more effective, more efficient, safer, novel, and radiation-free interventional procedures. The combined quantitative RF field and temperature sensing capability for local RF dosimetry has the potential to impact clinical practice by broadening the MRI safety envelope as well as contributing to the fundamental understanding of coupling effects such as B-field coupling, standing waves and gradient coil effects on local SAR.

尽管与 MRI 相关的不良事件很少见，但射频感应加热引起的安全问题具有重大意义。 对临床使用的影响，特别是对于越来越多的使用医疗植入物的患者。现行法规 基于估计的全身吸收率（SAR）对射频功率水平施加不必要的限制， 有时会降低诊断功效，而即使是这些低水平也会对特定的药物产生安全问题 患者。具有局部电场和个体患者温度测量功能的微型传感器 扫描期间可以减轻这些限制，同时提高安全性。这些传感器也会产生影响 在介入 MRI 应用中，有源标记，本质上是局部测量 RF 的微型线圈 信号，提供最佳的设备可见性。然而，这些标记会受到射频感应加热的影响 传输线，这个问题在高场 MR 系统中会加剧，目前还没有解决方案 满足所有机械和电气约束的解决方案。我们最近开发了一种微型声学 光学 (AO) RF 场传感器，通过光纤（而不是传导）检测和传输 RF 信号 传输线，因此完全不受射频感应加热和电磁干扰。这 同一设备可以测量温度以及局部 E/H 场，以进行 SAR 评估 加上正确设计的天线。在此应用中，我们的目标是优化 AO 传感器的设计 利用 0.55T、1.5T 和 3T 系统拉莫尔频率下光纤的独特机械共振 使用微加工技术制造具有薄膜压电换能器的装置。我们还推荐一本小说 将这些 AO 射频场传感器嵌入到可符合任何商业标准的套管中的封装策略 可用MRI兼容导管，显着增加介入MRI的设备选择。这些 有源标记物和多参数E/H场传感器将根据最新的MRI安全性进行严格测试 标准并针对几种具有挑战性的心血管介入 MRI 程序进行了体内评估。 成功演示 AO 传感器作为具有非导电传输线的主动 MRI 标记物 将是更有效、更高效、更安全、新颖和无辐射介入治疗的重大发展 程序。用于局部射频剂量测定的定量射频场和温度传感能力相结合 通过扩大 MRI 安全范围以及促进临床实践的潜力 对 B 场耦合、驻波和梯度线圈效应等耦合效应的基本了解 在当地特别行政区。