Safe Ultrasonic Transmission Lines for MRI Catheters

用于 MRI 导管的安全超声波传输线

• 批准号: 8879142
• 负责人: F. Levent Degertekin
• 金额: $ 18.34万
• 依托单位: GEORGIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8879142
• 关键词: Address; Air; Aneurysm; Animal Model; Animals; Arteries; Atherosclerosis; Blood Vessels; Blood flow; Cardiovascular system; Catheterization; Catheters; Choking; Clinical; Clinical Trials; Collaborations; Complex; Coronary Arteriosclerosis; Coupled; Coupling; Detection; Device Designs; Device Safety; Devices; Diagnostic radiologic examination; Distal; Engineering; Environment; Fiber; Fluoroscopy; Frequencies; Goals; Health; Heating; Hospitalization; Image; Imagery; Imaging Device; In Vitro; Interferometry; Intervention; Ionizing radiation; Lasers; Length; Location; Magnetic Resonance Imaging; Measurement; Measures; Mechanics; Medical Imaging; Metals; Methods; Modeling; Morphologic artifacts; Motion; National Heart, Lung, and Blood Institute; Operative Surgical Procedures; Optics; Patients; Pattern; Performance; Perfusion; Peripheral; Physiological; Procedures; Radiation; Relative (related person); Research; Research Personnel; Resources; Risk; Roentgen Rays; Running; Scheme; Signal Transduction; Slice; Structure; Techniques; Temperature; Testing; Therapeutic; Time; Translating; Ultrasonic Transducer; Ultrasonic wave; Ultrasonics; Ultrasonography; United States National Institutes of Health; Universities; base; clinical application; congenital heart disorder; cost effective; design; detector; image guided; image guided intervention; in vivo; ionization; magnetic field; minimally invasive; novel; operation; optical fiber; optical sensor; preclinical evaluation; prototype; radio frequency; research clinical testing; safety testing; soft tissue; transmission process

DESCRIPTION (provided by applicant): Catheter based minimally invasive interventions are becoming a preferred method as compared to surgical procedures due to the reduction of operation time, patient discomfort, hospitalization time, and procedure related risks. While X-ray fluoroscopy is widely used as a imaging guidance for the minimally invasive procedures such as treatment of obstructive coronary artery disease, peripheral artery atherosclerosis and aneurysm, and structural or congenital heart disease, magnetic resonance imaging (MRI) can provide superior soft tissue contrast while eliminating the ionization radiation exposure on both patient and operator in these procedures. MRI also provides multi slice imaging and allows physiological measurements such as blood flow, temperature, perfusion and motion. A significant issue with MRI guided interventions is that most traditional interventional devices (catheters, guidewires etc.) either invisible or not suitable for use under MRI. Active receive-onl devices using small coils or dipole antennae on the catheter shaft to detect the RF signals for device location and/or orientation under MRI use long conductive transmission lines. These approaches are problematic as RF induced heating over long conductor components of the devices needs to be addressed before moving on clinical trials. Although promising improvements in terms of RF induced heating problem have been achieved by detuning, RF chokes or transformers, none of these techniques can offer active device design that can have clinically acceptable mechanical performance. In this application, we aim to develop a clinical-grade active catheter device that does not need long conductor transmission lines for active device visualization under MRI. The active catheter design incorporates a distal loop coil that is electrically connected to an ultrasonic transducer having a comparable profile. This ultrasonic transducer induces ultrasonic waves at the Larmor frequency at the distal end of a dielectric optical fiber that runs along the active catheter shaft. This optical fiber serves as the transmission line instead of a conductor, eliminating the RF induced heating. The strain generated by the ultrasound transducer will be measured using optical interferometry by coupling a laser at the proximal end of the optical fiber using the acousto-optical effect. A fiber embedded Bragg reflector grating will be used for this purpose. The active devices will be designed, fabricated and incorporated into clinical grade catheter prototypes. The prototypes will be tested under MRI: in-vitro using specially prepared phantoms and in-vivo in large animals at NHLBI facilities.

描述（由申请人提供）：与外科手术相比，由于减少了手术时间、患者不适、住院时间和手术相关风险，基于导管的微创干预正在成为首选方法。虽然 X 射线透视广泛用作微创手术的成像指导，例如治疗阻塞性冠状动脉疾病、外周动脉粥样硬化和动脉瘤以及结构性或先天性心脏病，但磁共振成像 (MRI) 可以提供卓越的软组织成像对比，同时消除这些手术中患者和操作员受到的电离辐射暴露。 MRI 还提供多切片成像，并允许进行生理测量，例如血流、温度、灌注和运动。 MRI 引导干预的一个重要问题是大多数传统介入设备（导管、导丝等）要么不可见，要么不适合在 MRI 下使用。有源接收设备使用导管轴上的小线圈或偶极天线来检测 RF 信号，以便在 MRI 下定位和/或定向设备，并使用长传导传输线。这些方法存在问题，因为在进行临床试验之前需要解决设备长导体组件上的射频感应加热问题。尽管通过失谐、射频扼流圈或变压器已经在射频感应加热问题方面取得了有希望的改善，但这些技术都无法提供具有临床可接受的机械性能的有源器件设计。在此应用中，我们的目标是开发一种临床级有源导管装置，不需要长导体传输线即可在 MRI 下实现有源装置可视化。有源导管设计包含远端环形线圈，该线圈电连接到具有类似轮廓的超声换能器。该超声换能器在沿着有源导管轴延伸的介电光纤的远端处产生拉莫尔频率的超声波。该光纤充当传输线而不是导体，从而消除了射频感应加热。超声换能器产生的应变将通过利用声光效应在光纤近端耦合激光来使用光学干涉测量来测量。一种纤维 嵌入式布拉格反射光栅将用于此目的。有源装置将被设计、制造并整合到临床级导管原型中。这些原型将在 MRI 下进行测试：使用专门准备的模型进行体外测试，并在 NHLBI 设施中对大型动物进行体内测试。