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: 9917421
• 负责人: F. Levent Degertekin
• 金额: $ 45.33万
• 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/9917421
• 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 临床使用的影响，尤其是对越来越多的医疗植入物患者的影响。当前法规 根据估计的全身吸收率（SAR），对RF功率水平施加了不必要的限制， 有时会降低诊断功效 患者。具有局部电子场和温度测量能力的微型传感器对个别患者 在扫描过程中，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 在介入的MRI应用中，主动标记物基本上是在局部测量RF的微型线圈 信号，提供最佳的设备可见性。但是，这些标记遭受了RF诱导的电导加热 传输线，这是一个在高级领域MR系统中加剧的问题，目前没有 满足所有机械和电限制的解决方案。我们最近开发了一个微型的声音 - 光学（AO）RF场传感器，可检测并通过光纤传输RF信号而不是导电 传输线，因此完全没有RF诱导的加热和电磁干扰。这 同一设备有可能测量温度以及局部E/H场进行SAR评估 再加上正确设计的天线。在此应用程序中，我们旨在优化AO传感器的设计 在0.55t，1.5t和3T系统的Larmor频率下使用光纤的独特机械共振 使用微加工技术与薄膜压电传感器制造设备。我们也提出了一本小说 包装策略将这些AO RF现场传感器嵌入袖子中，可以符合任何商业上的措施 可用的MRI兼容导管，可显着增加介入MRI的设备选项。这些 主动标记和多参数E/H场传感器将根据最新的MRI安全进行严格测试 标准和在体内评估了几种具有挑战性的心血管介入MRI程序。 成功演示了AO传感器作为具有非导向传输线的主动MRI标记 将是更有效，更高效，更安全，新颖和无辐射介入的重大发展 程序。局部RF剂量测定法的组合定量RF场和温度感应能力具有 通过扩大MRI安全包络以及有助于影响临床实践的潜力 对耦合效应的基本了解，例如B场耦合，驻波和梯度线圈效应 在当地的SAR上。