Advanced MRI Technology in Safety & Intervention

描述（由申请人提供）：该续期拨款响应BRG PAR-13-1371，用于开发用于体内监测的非侵入性和非破坏性成像方法；新型诊断和医疗器械；新的生物工程方法治疗心血管疾病。该基金的目标是动脉粥样硬化，在晚期疾病中，以脂质、钙化和纤维帽病变为特征，其破裂是中风、心脏病发作和死亡的主要原因。虽然通常通过x线导管诊断，但x线不能评估斑块的内容、破裂的易感性或早期壁厚。我们的目标是开发一种新颖、安全、微创、快速、高分辨率的心血管成像方式，采用高场血管内磁共振成像（MRI）来评估和监测疾病，并提供靶向治疗。在拨款到期期间，我们创造了新的剂量学工具，用于在MRI期间测试内部设备的安全性。我们从理论和实验上证明，内部探测器的信噪比随着MRI场强的平方而增加，至少可达7特斯拉(T)。这使得在3T时80μm的IVMRI和在7T时40- 50μm的IVMRI能够显示斑块的形态。我们开发了一种新的μ成像方法，“MRI内窥镜”，它提供了一种本质上锁定在探针视点上的图像流，速度高达2 fr/s。由于40-50μm的IVMRI分辨率现在在可以识别易破裂斑块的范围内，并且由于在更高的MRI场下也可以对移动脂质进行化学选择性成像，因此通过IVMRI表征易损斑块的关键属性-薄纤维帽和移动脂质含量的可能性现在存在。但技术问题依然存在：我们需要更快的IVMRI，降低对运动的敏感度。我们需要一种化学选择性IVMRI方法。我们不知道IVMRI与其他IV方式-IV超声（IVUS）或光学相干断层扫描（OCT）相比如何。如果我们发现疾病，我们能干预吗？这次更新解决了所有这些关键问题。Aim 1使用新颖的稀疏采样和帧移方法创建了高速实时、运动不敏感的IVMRI功能。目的2开发高场40-50μm IV MRI和化学选择性脂质成像来表征斑块帽和内容物。目的3进行体外和体内IVMRI、OCT和IVUS的比较研究。Aim 4创建了一个高分辨率ivmri靶向的介入平台，用于血管成形术、细胞和超声消融治疗。该项目在第一笔拨款和新的前期工作的支持下，可以为促进心血管疾病的认识和治疗提供重要的新的静脉成像和介入工具。

DESCRIPTION (provided by applicant): This renewal grant responds to BRG PAR-13-1371 for the development of noninvasive and nondestructive imaging methods for in vivo monitoring; novel diagnostic and medical devices; and new bioengineering ap- proaches to cardiovascular treatment. The grant targets atherosclerosis, which in advanced disease, is characterized by lesions with lipids, calcification, and fibrous caps whose rupture are a leading cause of stroke, heart attack and death. While typically diagnosed by X-ray catheterization, X-ray can't assess plaque contents, vulnerability to rupture, or early stage wall-thickening. Our goal is to develop a novel, safe, mini- mally-invasive, fast, high-resolution, cardiovascular imaging modality employing high-field intravascular (IV) magnetic resonance imaging (MRI), to assess and monitor disease, and provide targeted therapy delivery. In the expiring grant period we created novel dosimetry tools for testing the safety of internal devices dur- ing MRI. We showed theoretically and experimentally that the signal-to-noise ratio of internal detectors in- creased with MRI field strength-squared, at least up to 7 Tesla (T). This enabled 80μm IVMRI at 3T and 40- 50μm at 7T to visualize plaque morphology. We developed a new μ-imaging method, 'MRI endoscopy' that provides a stream of images intrinsically locked to the probe's viewpoint at up to 2 fr/s. Because IVMRI resolution at 40-50μm is now within a range that could identify plaques vulnerable to rupture, and because chemically-selective imaging of mobile lipids is also possible at higher MRI fields, the possibility of character- izing key attributes of vulnerable plaque-thin fibrous caps and mobile lipid contents by IVMRI, now exists. But technical issues remain: we need still faster IVMRI, and reduced sensitivity to motion. We need a method of chemically selective IVMRI. We don't know how IVMRI compares with other IV modalities-IV ul- trasound (IVUS) or optical coherence tomography (OCT). And if we see disease, can we intervene? This re- newal addresses all these key questions. Aim 1 creates a high-speed real-time, motion-insensitive IVMRI capability using novel sparse sampling and frame-shifting methods. Aim 2 develops high-field 40-50μm IV MRI and chemically-selective lipid imaging to characterize plaque caps and contents. Aim 3 performs com- parative studies in vitro and in vivo of IVMRI, OCT, and IVUS. Aim 4 creates an interventional platform for high-resolution IVMRI-targeting, demonstrated for angioplasty, and cellular and ultrasound ablation thera- pies. This project, supported by progress in the 1st grant and new preliminary work, can provide important new IV imaging and interventional tools to advance understanding and treatment of cardiovascular disease.