Improved sensitivity and safety for endovascular MR imaging at 3T

提高 3T 血管内 MR 成像的灵敏度和安全性

基本信息

批准号：
9207468
负责人：
Steven William Hetts
金额：
$ 19.81万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-02-01 至 2019-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9207468
关键词：
Alloys Aneurysm Animal Model Area Balloon Angioplasty Behavior Biological Blood Flow Velocity Cardiovascular Diseases Catheterization Catheters Cause of Death Characteristics Chemicals Clinical Coiled Bodies Copper Deposition Detection Development Devices Diagnosis Diffusion Disease Elements Engineering Evaluation Family suidae Fiber Optics Frequencies Future Goals Guidelines Heating Image Imaging Techniques In Vitro Intervention Lead Location Magnetic Resonance Imaging Magnetism Malignant Neoplasms Maps Measures Memory Metals Methods Modeling Morbidity - disease rate Morphologic artifacts Nickel Nonionizing Radiation Operative Surgical Procedures Outcome Pathology Patients Performance Perfusion Play Predisposition Procedures Property RF coil Recovery Resolution Roentgen Rays Role Safety Sampling Shapes Site Stents Stroke Structure Techniques Technology Temperature Testing Thermometers Time Tissues Titanium United States Validation Vascular Diseases absorption base clinical translation clinically relevant design design and construction diagnosis evaluation disability experimental study hazard image guided intervention imaging modality improved in vivo interest magnetic field metabolomics minimally invasive models and simulation mortality neurovascular nitinol operation phantom model public health relevance sensor simulation soft tissue success transmission process

项目摘要

DESCRIPTION (provided by applicant): Minimally invasive image-guided interventions such as balloon angioplasty, stent placement, and coiling of aneurysms, provide reduced mortality, morbidity, and recovery times. Consequently they are increasingly and rapidly replacing invasive surgical procedures in the treatment of patients suffering from vascular disease. In the endovascular image-guided interventions, MRI is advantageous over other commonly-used imaging modalities (e.g., x-ray and CT) due to its non-ionizing radiation characteristic and its ability to provide soft tissue contrast, tissue chemical composition, and functional information, including blood flow velocities, perfusion and diffusion, and tissue metabolomics. In interventional procedures, it is critically important to accurately and rapidly detect the actual location of the endovascular devices or catheters and also the site of the pathology to be treated. In contrast to global detection in which the MR body coil is used for visualizing the catheter, local detection using an RF coil mounted on the tip of the endovascular catheter provides high sensitivity, allowing accelerated imaging and more accurate catheter localization. The increased sensitivity of the catheter coils is also critical in obtaining the required high spaial resolution. In current catheter coil designs, the coil's long and 'hot' leads exposed to surroundin tissues significantly increase the coil losses, leading to degraded detection sensitivity. They als create a safety hazard because of augmented RF energy deposition or specific absorption rate (SAR) along the leads during RF transmit, resulting in locally elevated temperatures in adjacent tissue. With increased operation frequency, these problems are more pronounced at high magnetic fields (e.g., 3T). In addition, the requirement of lumped capacitors in RF coils makes it challenging to incorporate such bulky structures into miniature endovascular devices. In fact, the lack of efficient and practical catheter RF coils has become a major hindrance for further development and clinical translation of endovascular image-guided interventions. In this project, we propose to develop whole new catheter RF coils at the high field of 3T using the recently introduced transmission line resonator (TLR) RF coil technology. The proposed TLR catheter coils are characterized by high detection sensitivity, reduced E-fields/SAR along the immersed catheter, and compact physical size. The major goals of this project are: 1) design and construction of new types of catheter RF coils at 3T using the TLR technology, 2) establishment of numerical models to understand the TLR catheter coils with and without load in resonant frequency, B1-field efficiency, imaging coverage, E-field distribution, and SAR/safety, and 3) validation of proposed catheter coil technology via MR imaging experiments and performance comparison with existing lumped-element catheter coils and safety assessment in vitro and in vivo. Successful outcome of this project would result in significant advances in catheter engineering that are critical to the future success of MRI guided clinical endovascular interventions.

描述（由申请人提供）：微创图像引导干预措施，例如球囊血管成形术、支架置入术和动脉瘤弹簧圈栓塞术，可降低死亡率、发病率和恢复时间，并在治疗中越来越多地迅速取代侵入性外科手术。在血管内图像引导干预中，MRI 优于其他常用成像方式（例如 X 射线和 CT）。由于其非电离辐射特性及其提供软组织对比度、组织化学成分和功能信息（包括血流速度、灌注和扩散以及组织代谢组学）的能力，在介入手术中，准确、快速地检测至关重要。血管内装置或导管的实际位置以及待治疗的病理部位与使用 MR 身体线圈来可视化导管的全局检测相反，使用安装在尖端的射频线圈进行局部检测。血管内导管提供高灵敏度，允许加速成像和更准确的导管定位。在当前的导管线圈设计中，暴露于周围组织的长而“热”的引线显着增加，导管线圈的灵敏度提高也至关重要。线圈损耗，导致检测灵敏度下降，因为射频发射期间沿引线的射频能量沉积或比吸收率 (SAR) 增加，导致邻近组织局部温度升高，从而产生安全隐患。这些问题在此外，射频线圈中集总电容器的要求使得将如此庞大的结构融入微型血管内装置中具有挑战性。事实上，缺乏高效且实用的导管射频线圈已成为主要障碍。为了进一步开发和临床转化血管内图像引导干预措施，在该项目中，我们建议使用最近推出的传输线谐振器 (TLR) 开发 3T 高场的全新导管射频线圈。射频线圈技术。所提出的 TLR 导管线圈具有检测灵敏度高、沿浸入式导管的电场/SAR 减少以及物理尺寸紧凑的特点。该项目的主要目标是：1）新型导管的设计和构造。使用 TLR 技术的 3T 射频线圈，2) 建立数值模型以了解带负载和不带负载的 TLR 导管线圈的谐振频率、B1 场效率、成像覆盖范围、电场分布和SAR/安全性，3) 通过 MR 成像实验验证拟议的导管线圈技术，并与现有集总元件导管线圈进行性能比较，并进行体外和体内安全评估。该项目的成功结果将导致导管工程的重大进步。对于 MRI 引导的临床血管内介入治疗的未来成功至关重要。