Endovascular Magnetic Catheter for Interventional MRI

用于介入 MRI 的血管内磁力导管

• 批准号: 8184689
• 负责人: Steven William Hetts
• 金额: $ 54.34万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8184689
• 关键词: Achievement; Acute; Address; Anatomy; Aneurysm; Animal Model; Arrhythmia; Atherosclerosis; Blood Vessels; Blood coagulation; Blood flow; Brain Aneurysms; Cardiovascular Diseases; Catheterization; Catheters; Cause of Death; Characteristics; Clinical; Clinical Treatment; Complication; Copper; Decision Making; Deposition; Devices; Diagnosis; Diagnostic; Diffusion weighted imaging; Dimensions; Disease; Dose; Environment; Equation; Family suidae; Fluoroscopy; Friction; Functional Imaging; Goals; Hand; Health Personnel; Heating; Image; Imagery; Imaging Techniques; In Vitro; Infarction; Intervention; Ionizing radiation; Ischemic Stroke; Joystick; Lasers; Lead; Magnetic Resonance Imaging; Magnetism; Malignant Neoplasms; Measures; Mediating; Medical Device; Methods; Modality; Modeling; Monitor; Morbidity - disease rate; Morphologic artifacts; Organ; Outcome; Parents; Particulate; Patients; Performance; Perfusion; Physicians; Physiological; Physiology; Play; Positioning Attribute; Procedures; Process; Public Health; Research; Resolution; Roentgen Rays; Role; Running; Safety; Saline; Simulate; Site; Solid Neoplasm; Speed; Stroke; System; Techniques; Technology; Temperature; Testing; Therapeutic; Therapeutic Embolization; Time; Tissues; Treatment Efficacy; United States; Work; base; clinical practice; cost; design; diagnosis evaluation; disability; experience; improved; in vivo; intravenous drip; lithography; magnetic field; miniaturize; minimally invasive; mortality; optical imaging; pre-clinical; prototype; soft tissue; success; thrombolysis; treatment strategy; tumor

DESCRIPTION (provided by applicant): The overall goal of this project is to develop a new minimally invasive medical device: a working prototype catheter that is remotely magnetically controlled for use in the endovascular interventional magnetic resonance imaging (MRI) environment. Several major public health threats, including ischemic stroke, brain aneurysm, solid tumors, atherosclerosis, and cardiac arrhythmias are currently diagnosed and treated endovascularly under x-ray fluoroscopic guidance. Although x-ray fluoroscopy has high spatial and temporal resolution, it only visualizes blood vessels as opposed to the soft tissues and organs ultimately supplied by those blood vessels. Whereas x-ray fluoroscopy uses ionizing radiation, which in large doses can have deleterious effects both on patients and health care providers; MRI does not use ionizing radiation. Performing endovascular procedures under MRI guidance is a key application of the growing field of interventional MRI. Fast yet high resolution MR imaging techniques have been developed in recent years, allowing frame rates comparable to those achieved with x-ray fluoroscopy. Performing procedures under MRI allows use of the wide array of MR anatomic and physiologic imaging techniques during an intervention: diffusion weighted imaging to evaluate for tissue infarction, perfusion imaging to assess for organ blood flow, high resolution anatomic imaging to visualize tissues surrounding and downstream from a catheterized blood vessel. Having such MRI information can help guide the interventional physician's decisions as to when a desired therapeutic result has been achieved or when an undesired procedural complication has occurred, whereas under x-ray guidance, parameters such as perfusion and infarction can only be inferred. If vascular interventions can be performed under MRI guidance, then real time physiologic MR imaging can be used to augment intraprocedural decision making, potentially allowing new patients to receive endovascular therapy and improving clinical outcomes. In addition to the imaging advantages of MRI, the strong homogeneous magnetic (B0) field inside the MRI scanner provides a unique opportunity for catheter tip navigation by remote control. If a tiny magnetic moment is created on the tip of the catheter by application of a small electrical current to copper coils on the catheter tip, then the tip of the catheter will move to align with the bore of the MRI scanner (the direction of the B0field). If one such coil is placed at the catheter tip, it can be deflected in one plane by remote control or turned by the practitioner's hand to deflect in another plane. If three such coils are placed on the catheter tip, then remote controlled deflection can be achieved in three dimensions even without the hand of the interventionalist. This technology potentially will allow better navigation of small, tortuous blood vessels that are currently difficult to catheterize due to build-up of friction at the many vascular bends between the femoral access site and the target blood vessel. Low levels of current supplied to the catheter coils also permits active visualization of the catheter tip, which otherwise can be difficult to see in the MR environment. We previously developed a laser lathe lithography technique to synthesize catheters tipped with copper coils in up to three orthogonal axes. We used real-time MRI techniques to visualize the catheter tip and navigate simple vascular phantoms in a clinical MRI scanner. We measured heating within the catheter and its surroundings both in vitro and in vivo. We also derived and validated equations to characterize the relationship between catheter coil geometry, applied current, catheter stiffness, magnetic field strength, and resulting catheter tip deflections. In this new proposal, we will build upon earlier research with the following specific aims: 1. Specific Aim 1: Refine catheter shaft and tip design to improve functionality; 2. Specific Aim 2: Evaluate MR imaging strategies to optimize catheter visualization and minimize artifacts; 3. Specific Aim 3: Test catheter navigation and imaging in vitro in the 1.5 T and 3.0 T MRI environments; 4. Specific Aim 4: Evaluate in vivo catheter navigation and imaging in animal models at 1.5 T; 5. Specific Aim 5: Assess catheter safety at 1.5 T; 6. Specific Aim 6: Assess the performance of the catheter system in animal models of key MR-guided interventions: thrombolysis (as for acute ischemic stroke treatment) and particulate embolization for controlled tissue infarction (as for tumor treatment). At the end of the proposed project period, the magnetic catheter system will be a viable device for improving the speed and efficacy of interventions performed in the MR environment. It thus will stand to revolutionize the clinical treatment of diseases that would benefit from real time physiologic tissue monitoring during endovascular therapy. PUBLIC HEALTH RELEVANCE: Stroke, cancer, and cardiovascular disease are the major causes of death and disability in the United States and MRI plays an important role in the diagnosis and evaluation of these disorders. The technology to be developed in this project exploits the magnetic environment of the MRI scanner to manipulate catheters and therapeutic devices, thereby transforming MRI into a therapeutic modality as well as a diagnostic one. This could ultimately lead to safer and more efficacious treatment strategies for several major causes of morbidity and mortality.

描述（由申请人提供）：该项目的总体目标是开发一种新的微创医疗设备：一种工作原型导管，可远程磁性控制，可用于内血管内介入的介入磁共振成像（MRI）环境。 在X射线荧光镜指导下，目前已诊断并治疗了几种主要的公共卫生威胁，包括缺血性中风，脑动脉瘤，实体瘤，动脉粥样硬化和心律不齐。尽管X射线透视镜具有很高的空间和时间分辨率，但它仅可视化血管，而不是这些血管最终提供的软组织和器官。 X射线透视镜使用电离辐射，而大剂量的辐射可能对患者和医疗保健提供者产生有害影响。 MRI不使用电离辐射。 在MRI指南下进行血管内手术是介入MRI的不断增长领域的关键应用。 近年来已经开发了快速但高分辨率的MR成像技术，允许与X射线荧光镜检查相当的帧速率。 MRI下的执行程序允许在干预过程中使用广泛的MR解剖学和生理成像技术：扩散加权成像以评估组织梗塞，灌注成像以评估器官血流，高分辨率解剖学成像，以可视化周围和下游的导管血管的组织。拥有此类MRI信息可以帮助指导介入的医生关于何时获得所需治疗结果或发生不希望的程序并发症的决定，而在X射线指导下，只能推断出灌注和梗塞等参数。如果可以在MRI指导下进行血管干预措施，则可以使用实时生理MR成像来增强手术室内决策，从而有可能允许新患者接受血管内治疗并改善临床结果。 除了MRI的成像优势外，MRI扫描仪内部强均匀磁（B0）场为通过遥控器进行导管尖端导航提供了独特的机会。如果通过将小电流应用于导管尖端上的铜线圈，在导管的尖端上产生微小的磁矩，则导管的尖端将移动以与MRI扫描仪的孔（B0场的方向）保持一致。如果将一个这样的线圈放在导管尖端，则可以通过遥控器将其偏转在一个平面中，也可以由从业人员的手转动以在另一个平面上偏转。如果将三个这样的线圈放在导管尖端上，那么即使没有介入主义者的手，也可以在三个维度上实现遥控偏转。这项技术可能会允许更好地导航小型，曲折的血管，这些血管目前由于在股骨通道部位和靶血管之间的许多血管弯曲处的摩擦而难以导管。提供给导管线圈的电流的低水平也允许对导管尖端进行主动可视化，否则在MR环境中可能很难看到。 我们以前开发了一种激光车床光刻技术，以合成在多达三个正交轴上用铜线圈倾斜的导管。我们使用实时MRI技术可视化导管尖端并在临床MRI扫描仪中导航简单的血管幻像。我们在体外和体内测量了导管及其周围环境中的加热。我们还得出并验证了方程式，以表征导管线圈几何形状，施加电流，导管刚度，磁场强度和产生的导管尖端偏转之间的关系。在这项新提案中，我们将以以下特定目的进行早期研究，以：1。特定目的1：完善导管轴和尖端设计以提高功能； 2。具体目标2：评估MR成像策略以优化导管可视化并最小化伪影； 3。特定目标3：在1.5 T和3.0 T MRI环境中在体外测试导管导航和成像； 4。特定目标4：评估1.5 T动物模型中的体内导管导航和成像； 5。具体目标5：评估1.5 t的导管安全； 6。特定目标6：评估关键MR引导干预措施动物模型中导管系统的性能：溶栓（如急性缺血性卒中治疗）和受控组织梗死的颗粒栓塞（如肿瘤治疗）。 在拟议的项目期结束时，磁导管系统将是提高MR环境中执行干预措施的速度和功效的可行装置。因此，它将彻底改变疾病的临床治疗，这些疾病将受益于血管内治疗期间的实时生理组织监测。 公共卫生相关性：中风，癌症和心血管疾病是美国死亡和残疾的主要原因，MRI在诊断和评估这些疾病中起着重要作用。该项目中要开发的技术利用了MRI扫描仪的磁性环境来操纵导管和治疗设备，从而将MRI转化为治疗方式和诊断方法。这最终可能会导致几种主要原因和死亡率的主要原因更安全，更有效的治疗策略。