Advanced MRI Technology in Safety & Intervention

描述（由申请人提供）：该更新资助响应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;以及心血管治疗的新生物工程方法。这项拨款的目标是动脉粥样硬化，在晚期疾病中，其特征是脂质、钙化和纤维帽的病变，纤维帽的破裂是中风、心脏病发作和死亡的主要原因。虽然通常通过X射线导管插入术进行诊断，但X射线不能评估斑块内容物、破裂的脆弱性或早期壁增厚。我们的目标是开发一种采用高场血管内（IV）磁共振成像（MRI）的新型、安全、微创、快速、高分辨率心血管成像模式，以评估和监测疾病，并提供靶向治疗。 在即将到期的资助期内，我们创建了新的剂量测定工具，用于测试MRI期间内部器械的安全性。我们从理论上和实验上表明，内部探测器的信噪比随着MRI场强平方的增加而增加，至少高达7特斯拉（T）。这使得3 T下的80μm IVMRI和7 T下的40- 50μm IVMRI能够可视化斑块形态。我们开发了一种新的μ成像方法，“MRI内窥镜”，它提供了一个图像流，本质上锁定到探头的观点，高达2 fr/s。由于40-50μm的IVMRI分辨率现在处于可以识别易破裂斑块的范围内，并且由于移动的脂质的化学选择性成像在更高的MRI场也是可能的，因此现在存在通过IVMRI表征易损斑块的关键属性-薄纤维帽和移动的脂质含量的可能性。 但技术问题仍然存在：我们需要更快的IVMRI，并降低对运动的敏感性。我们需要一种化学选择性的IVMRI方法。我们不知道IVMRI与其他IV模式（IV超声（IVUS）或光学相干断层扫描（OCT））相比如何。如果我们看到疾病，我们能干预吗？这次更新解决了所有这些关键问题。目标1使用新颖的稀疏采样和帧移位方法创建高速实时、运动不敏感的IVMRI能力。目的2发展高场40-50μm IV MRI和化学选择性脂质成像以表征斑块帽和内容物。目的3对IVMRI、OCT和IVUS进行体内外对比研究。目标4创建了一个用于高分辨率IVMRI靶向的介入平台，用于血管成形术以及细胞和超声消融治疗。该项目得到了第一笔赠款和新的初步工作的支持，可以提供重要的新的IV成像和介入工具，以促进对心血管疾病的理解和治疗。

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.