Safe Ultrasonic Transmission Lines for MRI Catheters

用于 MRI 导管的安全超声波传输线

• 批准号: 8772802
• 负责人: F. Levent Degertekin
• 金额: $ 23.63万
• 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 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8772802
• 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; 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; Radio; 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 intervention; in vivo; ionization; magnetic field; minimally invasive; novel; operation; optical fiber; optical sensor; preclinical evaluation; prototype; public health relevance; 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）：由于减少了手术时间，患者不适，住院时间和相关风险，因此与手术程序相比，基于导管的微创干预措施与手术程序相比已成为首选方法。 X射线透视镜被广泛用作最小侵入性程序的成像指南，例如治疗阻塞性冠状动脉疾病，周围动脉粥样硬化和动脉瘤以及结构或先天性心脏病，但磁共振成像（MRI）可以提供出色的软组织。在这些程序中消除患者和操作员对患者和操作员的电离辐射暴露时的对比。 MRI还提供多切片成像，并允许生理测量，例如血流，温度，灌注和运动。 MRI指导干预措施的一个重要问题是，大多数传统的介入设备（导管，指导线等）是无形的或不适合在MRI下使用的。使用导管轴上的小线圈或偶极天线接收接收器件，以检测RF信号的设备位置和/或MRI下的方向使用较长的导电传输线。这些方法是有问题的，因为在进行临床试验之前，需要解决RF诱导的在设备的长导体组件上加热。尽管通过失谐，RF窒息或变压器可以实现RF诱导的加热问题的有希望的改善，但这些技术都无法提供可以具有临床上可接受的机械性能的主动设备设计。在此应用中，我们旨在开发一种临床级活动导管设备，该导管设备不需要长时间的导体传输线即可在MRI下进行主动设备可视化。活性导管设计结合了一个远端环线圈，该线圈是电的远端环线圈，该线圈是电与具有可比曲线的超声传感器连接在一起的。这种超声传感器在沿介电光纤纤维的远端诱导Larmor频率下诱导超声波，该介电光纤沿着活性导管轴延伸。该光纤用作传输线代替导体，消除了RF诱导的加热。超声换能器产生的应变将通过光学干涉仪使用光纤维近端的激光耦合，以使用声学效果来测量。纤维 嵌入式bragg反射器光栅将用于此目的。活动设备将被设计，制造和合并到临床级导管原型中。原型将在MRI下进行测试：使用专门准备的幻象和体内的VITRO在NHLBI设施的大型动物中进行测试。