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Advanced Intravascular MRI for Assessing Atherosclerosis

用于评估动脉粥样硬化的先进血管内 MRI

基本信息

批准号：
8076898
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
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-01 至 2013-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8076898
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 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

项目摘要

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和死亡的主要原因。疾病的存在和严重程度通常通过 X 射线导管插入术中的管腔狭窄来诊断。由于 X 射线成像无法显示血管壁，因此无法评估晚期斑块形成之前的过程或斑块破裂的脆弱性。目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 将此类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) 无需电离辐射即可对狭窄和血管壁病理进行精确、高对比度的评估。此前，我们实验室开发了直径约 1 毫米的生物相容性血管内导丝作为临床 1.5 Tesla (T) 扫描仪的主动 MRI 探测器，但尚未得到广泛使用。最大限度地提高速度、灵敏度和空间分辨率是临床使用的关键。虽然全身 3T MRI 已成为一种新的临床研究标准，可提供比现有 1.5T 扫描仪更高的信噪比 (SNR)，但 IVMRI 探测器仅限于 1.5T，因此无法从任何 3T SNR 增益中受益。一个问题是，在其他条件不变的情况下，引入的金属器件在 3T 时的潜在发热比 1.5T 时增加了 4 倍。我们提供了新的初步实验和理论数据，证明 3T 与 1.5T 下等效血管内天线的 SNR 增益超过 3 倍，灵敏度或视场区域（表现出相同 SNR 的区域）增加超过 10 倍。我们证明，3T MRI 期间加热可以保持在安全水平内。这种性能提升为高对比度、高分辨率 IVMRI 用于动脉粥样硬化的体内评估提供了巨大的潜力。 Aim 1 开发并测试用于 3T MRI 的主动、生物相容性高 SNR、高 FOV 血管内导丝。图像引导设备跟踪需要高速 MRI。然而，传统 MRI 被锁定在扫描仪的参考系 (FoR) 上，需要耗时的“读出”设备位置来为新位置指定 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励，本质上将图像 FoR 锁定到探头的活动端。天线变成了“MR眼”，当它像内窥镜一样穿过动脉时，会生成它“看到”的图像。由于 MRI 激发的体积大大减少到探头附近，因此加热潜力大大降低。 Aim 3 在体内兔子动脉粥样硬化模型中测试了这些新技术，其中主动脉的直径与人类冠状动脉相当。这些发展将为未来人类使用奠定基础。