Advanced Intravascular MRI for Assessing Atherosclerosis

用于评估动脉粥样硬化的先进血管内 MRI

• 批准号: 7862316
• 负责人: PAUL A BOTTOMLEY
• 金额: $ 41万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7862316
• 关键词: Adoption; Adverse effects; Aorta; Area; Arterial Fatty Streak; Arteries; Atherosclerosis; Biocompatible; Blood Vessels; Caliber; Catheterization; Catheters; Clinic; Clinical; Clinical Research; Contrast Media; Coronary artery; Data; Data Analyses; Deposition; Detection; Development; Device Safety; Devices; Diagnosis; Diagnostic radiologic examination; Electromagnetic Fields; Endoscopes; Endoscopy; Exhibits; Eye; Feedback; Fluoroscopy; Frequencies; Future; Hand; Heating; Histology; Human; Image; In Vitro; Injury; Ionizing radiation; Laboratories; Lesion; Location; Magnetic Resonance Imaging; Measures; Methods; Modeling; Morbidity - disease rate; Morphology; National Heart, Lung, and Blood Institute; Noise; Oryctolagus cuniculus; Pathology; Patients; Performance; Phase; Physiologic pulse; Positioning Attribute; Process Assessment; Radio; Radio-Opaque; Reading; Research; Resolution; Roentgen Rays; Rupture; Safety; Sampling; Severities; Severity of illness; Signal Transduction; Site; Slice; Speed; Stenosis; Surface; System; Temperature; Testing; Thermometry; Time; Ultrasonography; Work; arterial lesion; base; calcification; design; design and construction; detector; electrical property; experience; image guided intervention; imaging detector; improved; in vitro testing; in vivo; mortality; new technology; operation; prototype

DESCRIPTION (provided by applicant): Atherosclerosis and its complications are leading causes of morbidity and mortality. The presence and severity of disease is typically diagnosed by luminal narrowing at X-ray catheterization. Because X-ray imaging does not visualize vessel walls, it does not allow assessment of processes that precede advanced plaque formation, or the vulnerability of plaques to rupture. Other current imaging approaches have difficulty distinguishing plaque components and with spatial and temporal resolution. Such issues are identified by NHLBI as central problems for image-guided intervention. Intravascular magnetic resonance imaging (IVMRI) promises precise, high-contrast assessment of stenoses and vessel wall pathology without ionizing radiation. Previously, ~1 mm diameter biocompatible intravascular guidewires were developed as active MRI detectors for clinical 1.5 Tesla (T) scanners in our laboratories, but have not gained wide use. Maximizing speed, sensitivity and spatial resolution are key to clinical use. While whole-body 3T MRI has emerged as a new clinical research standard, delivering higher signal-to-noise ratio (SNR) than existing 1.5T scanners, IVMRI detectors are limited to 1.5T, and thus have not benefited from any 3T SNR gain. One problem is a 4-fold increase in potential heating of introduced metallic devices at 3T vs 1.5T, all else being constant. We present new preliminary experimental and theoretical data demonstrating an over 3-fold gain in SNR and over 10-fold increase in the area of sensitivity or field-of-view (area exhibiting the same SNR) for equivalent intravascular antennae at 3T vs 1.5T. We show that heating can be kept within safe levels during 3T MRI. Such performance gains offer huge potential for high-contrast, high-resolution IVMRI for the in vivo assessment of atherosclerosis. Aim 1 develops and tests active, biocompatible high-SNR, high-FOV intravascular guidewires for 3T MRI. Image-guided device tracking requires high-speed MRI. However, conventional MRI is locked to the scanner's frame-of-reference (FoR), requiring time-consuming "read-out" of device location to prescribe MRI gradients for new locations. Aim 2 develops a new MRI approach that uses the antenna itself for excitation, intrinsically locking the image FoR to the active end of the probe. The antenna becomes an "MR-eye", generating images of what it "sees" as it courses through an artery like an endoscope. Because the MRI-excited volume is vastly reduced to the vicinity of the probe, heating potential is greatly reduced. Aim 3 tests these new technologies in an in vivo rabbit atherosclerosis model, where the aorta is of comparable diameter to human coronary arteries. These developments will form a basis for future human use.

描述（由申请人提供）：动脉粥样硬化及其并发症是发病率和死亡率的主要原因。疾病的存在和严重程度通常通过X射线导管插入术时的腔狭窄来诊断。由于X射线成像不会可视化容器壁，因此它不允许评估先进的斑块形成之前的过程，也不允许斑块破裂的脆弱性。当前的其他成像方法难以区分斑块成分以及空间和时间分辨率。 NHLBI将这些问题确定为图像引导干预的核心问题。血管内磁共振成像（IVMRI）有望对stenose和血管壁病理学的精确，高对比度评估，而无需电离辐射。以前，在我们的实验室中，直径约为1 mm的生物相容性生物相容性导线作为临床1.5 Tesla（T）扫描仪的主动MRI探测器开发，但尚未大量使用。最大化速度，灵敏度和空间分辨率是临床使用的关键。尽管全身3T MRI已成为一种新的临床研究标准，比现有的1.5T扫描仪提供了更高的信噪比（SNR），但IVMRI探测器的限制为1.5T，因此并未从任何3T SNR增益中受益。一个问题是，在3T vs 1.5t的引入金属设备的潜在加热中增加了4倍，所有其他均保持恒定。我们提供了新的初步实验和理论数据，表明SNR的增益超过3倍，敏感性或视野（表现出相同SNR的区域）在3T vs 1.5t时增加了10倍以上。我们表明，在3T MRI期间，加热可以保持在安全水平之内。这种性能增长为高分辨率，高分辨率IVMRI提供了巨大的潜力，用于对动脉粥样硬化的体内评估。 AIM 1开发和测试3T MRI的活性，生物相容性的高SNR，高纤维内血管内导线。图像指导的设备跟踪需要高速MRI。但是，传统的MRI已锁定到扫描仪的参考框架（For），需要设备位置的耗时的“读取”以开出新位置的MRI梯度。 AIM 2开发了一种新的MRI方法，该方法使用天线本身进行激发，将图像本质地锁定到探针的活跃端。天线变成了“ Mr-Eye”，从内窥镜像内窥镜一样通过动脉进行训练时产生了它“看到”的图像。由于MRI激发的体积大大减少到探针附近，因此加热潜力大大降低。 AIM 3在体内兔动脉粥样硬化模型中测试了这些新技术，其中主动脉与人冠状动脉的直径可比。这些发展将构成未来人类使用的基础。