Flow-mediated dilation by ultrasound imaging

描述（由申请人提供）：内皮功能障碍是动脉粥样硬化的早期标志，是许多疾病的重要心血管危险因素，包括高血压和糖尿病。因此，开发内皮功能障碍的无创测试是一项重要的工作。通过超声成像测量肱动脉血流介导的扩张提供了这种可能性，其应用已在各种临床研究中得到证实。尽管结果令人鼓舞，该技术不推荐常规临床应用，主要是因为其低灵敏度和大变异系数。该应用程序旨在克服这些限制。我们建议使用复合成像来提高图像质量；横断成像，以提高灵敏度和变异系数，和自动边界检测连续监测血管舒张超声检查。我们在流动幻影中测试了这些概念，并表明灵敏度可以比传统方法提高150倍。我们还演示了这项技术可以用于对人体进行成像。研究结果发表在最近的一篇文章中。在这个R21申请中，我们正在寻求对人体受试者进行可行性研究的支持。将在少数健康志愿者（N = 60）中测量血流介导的舒张。目的是证明使用复合和自动边界检测的肱动脉横断面超声成像比使用纵向成像的传统方法具有更高的灵敏度和可重复性。所提出的研究将导致一种可靠的方法来测量口蹄疫，适合常规临床应用。考虑到血管内皮功能障碍在心血管疾病中的广泛参与，以及超声成像是非侵入性的，适合重复检查，本研究将在筛查心血管风险、诊断动脉粥样硬化和监测治疗反应方面具有重要意义。

DESCRIPTION (provided by applicant): Endothelial dysfunction, an early marker of atherosclerosis, is a significant cardiovascular risk factor that is implicated for many diseases, including hypertension and diabetes. There is therefore a major effort to develop a noninvasive test for endothelial dysfunction. Flow-mediated dilation of the brachial artery measured by ultrasound imaging offers this possibility, and its use has been demonstrated in various clinical studies. Despite encouraging results, the technique is not recommended for routine clinical use, mainly because of its low sensitivity and large coefficient of variation. This application is designed to overcome these limits . We propose the use of compound imaging to enhance image quality; cross-sectional imaging to improve sensitivity and coefficient of variations, and automated boundary detection for continuous monitoring of vasodilation during ultrasound examination. We tested these concepts is flow phantoms and showed that sensitivity can be improved by as much as 150 times over the conventional method. We also demonstrated the technique could be used to image human subjects. The results were published in a recent article. In this R21 application, we are seeking support for a feasibility study in human subjects. Flow-mediated dilation will be measured in a small number (N = 60) of healthy volunteers . The goal is to demonstrate that ultrasound imaging of brachial artery cross-section using compounding and automated boundary detection have higher sensitivity and reproducibility than the conventional approach using longitudinal imaging. The proposed research will lead to a robust method for measuring FMD, suitable for routine clinical applications. Given the broad involvement of endothelial dysfunction in cardiovascular diseases and that ultrasound imaging is noninvasive and suitable for repeated examinations, the proposed research would have major implication in screening subjects for cardiovascular risks, diagnosing atherosclerosis and monitoring treatment responses.