VASCULAR FUNCTION BY MAGNETIC RESONANCE ANGIOGRAPHY

磁共振血管造影的血管功能

• 批准号: 6644178
• 负责人: HARRY A. SILBER
• 金额: $ 13.13万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-13 至 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6644178
• 关键词: HMG coA reductases; angiocardioultrasonography; angiography; artery; atherosclerosis; capillary bed; cardiovascular disorder diagnosis; computer data analysis; disease /disorder proneness /risk; enzyme inhibitors; hemodynamics; human subject; magnetic resonance imaging; myocardial infarction; pathologic process; patient oriented research; physiologic stressor; statistics /biometry; stimulus /response; vascular endothelium; vasodilation

It is unclear why individuals at risk for atherosclerosis develop more severe disease in some vascular beds than others, e.g. femoral arteries tend to develop much more severe disease than do brachial arteries. We hypothesize that these different susceptibilities are associated with regional differences in vascular endothelial function within those individuals. Wall shear stress is considered to be the primary hemodynamic stimulus for endothelial activity. Therefore, comparing the relationship between wall shear stress stimulus and endothelial response in different vascular beds may allow the evaluation of regional differences in endothelial function. Using phase-contrast magnetic resonance angiography, we have shown a linear relationship between wall shear stress during peak reactive hyperemia and resulting vessel dilatation in normal brachial arteries. We have also developed another method to assess endothelial stimulus response relationship by evaluating the time-course of endothelial regulation of wall shear stress following post-ischemic hyperemia, and a technique to assess circumferential distribution of wall shear stress in a single arterial cross-section. The aims of this project are 1) to determine whether the endothelial stimulus-response relationships are altered in the presence of cardiovascular risk factors and in the presence of vascular disease, 2) to determine whether the relationships are sensitive to changes in endothelial function after a 6-week course of an HMG-Co A reductase inhibitor in subjects with hyperlipidemia, and 3) to determine whether the relationships or the circumferential stress distribution differ in different vascular beds. The investigators anticipate that this study will improve the ability to distinguish between normal and impaired endothelial function, and will enhance the understanding of atherosclerosis development. The proposal will involve mentorship, training, and resources from cardiovascular clinical research experts and several world-renown divisions of Johns Hopkins: Cardiovascular MRI, Biomedical Engineering, and The School of Public Health. The mentors, collaborators, environment, and research plan are ideal for achieving the applicant's long-term goal of becoming an independent clinical investigator, applying innovative engineering techniques toward patient-oriented cardiovascular problems.

目前还不清楚为什么有动脉粥样硬化风险的个体在某些血管床中会比其他血管床发展出更严重的疾病，例如，动脉粥样硬化。股动脉往往比肱动脉发生更严重的疾病。我们假设这些不同的敏感性与这些个体内血管内皮功能的区域差异有关。壁剪切应力被认为是内皮活动的主要血流动力学刺激。因此，比较不同血管床的壁剪切应力刺激和内皮反应之间的关系可以允许评估内皮功能的区域差异。使用相差磁共振血管造影，我们显示了正常肱动脉峰值反应性充血期间的壁剪切应力与由此产生的血管扩张之间的线性关系。我们还开发了另一种通过评估缺血后充血后壁剪切应力的内皮调节的时间过程来评估内皮刺激反应关系的方法，以及评估单个动脉横截面中壁剪切应力的周向分布的技术。该项目的目的是 1) 确定在存在心血管危险因素和存在血管疾病的情况下内皮刺激-反应关系是否发生改变，2) 确定这些关系是否对心血管疾病后内皮功能的变化敏感。高脂血症受试者接受 HMG-Co A 还原酶抑制剂 6 周疗程，3) 确定不同血管床之间的关系或周向应力分布是否不同。研究人员预计这项研究将提高区分正常内皮功能和受损内皮功能的能力，并将增进对动脉粥样硬化发展的了解。该提案将涉及心血管临床研究专家和约翰·霍普金斯大学几个世界知名部门的指导、培训和资源：心血管核磁共振、生物医学工程和公共卫生学院。导师、合作者、环境和研究计划非常适合实现申请人成为独立临床研究者、应用创新工程技术解决以患者为导向的心血管问题的长期目标。