MAGNETIC RESONANCE CORONARY ANGIOGRAPHY

磁共振成像(MRI)作为一种非侵入性研究 冠状动脉成像中心导管检查的替代方法 几个研究小组已经提出了动脉。尽管 磁共振冠状动脉成像可行性的初步论证 血管造影术(MRCA)，临床上不用于常规评估 患有冠状动脉疾病的患者。我们最近已经证明，使用 作为实时呼吸门控装置的导航仪回波图像可以 制作冠状动脉的图像，使其可以用于 临床领域。然而，也存在着对以下问题的担忧和质疑 导航仪回波门控对图像精度的影响 获得。具体地说，导航仪回波上出现的狭窄 选通图像仍然不确定。MRCA可能会有一个领域 对临床领域的直接影响是评估和 经皮冠状动脉腔内术后再狭窄的处理 血管成形术(PTCA)。 本研究的总体目标是开发回声驱动的导航仪 磁共振冠状动脉造影术与冠状动脉低位测量 成为检测经皮腔内成形术后再狭窄的有用工具。具体的 本研究的目的是：1)对现实狭窄进行模型研究 冠脉血流幻影伴随着呼吸运动和搏动性血流至： A)比较2D和3D获取方法，并优化最有希望的 方法，b)确定多个信号的影响平均、高- 分辨率，导航仪回波驱动成像对狭窄的检测， C)调查冠状动脉血流动力学并评估是否存在狭窄 严重程度可以通过狭窄后的信号损失加血流来估计 速度测量，d)评估血管内对比的影响 确定狭窄严重程度的试剂，e)确定精确度和 优化导航仪回波驱动磁共振流量测量的准确性。2) 评价优化的MRCA技术的准确性和临床应用价值 用于检测PTCA术后患者的再狭窄。检查50名患者 在PTCA手术前后：a)优化的多信号平均， 高分辨率导航仪回波驱动磁共振冠状动脉成像序列 并将图像与x射线血管造影术进行比较，以及b)导航仪回波 驱动的MR相速度序列，并将结果与 用血管内超声进行测量。

Studies using magnetic resonance imaging (MRI) as a non-invasive alternative to cardiac catheterization for the imaging of coronary arteries have been presented by several research groups. Despite the preliminary demonstration of feasibility of magnetic resonance coronary angiography (MRCA), it is not used clinically for routine evaluation of patients with coronary artery disease. We have recently shown that using a navigator echo image as a real-time respiratory gating device can produce images of coronary arteries which may allow there use in the clinical arena. However, there are also concerns and questions about the impact of navigator echo gating on the accuracy of the images obtained. Specifically, the appearance of stenoses on navigator echo gating images remains uncertain. One area where MRCA could have an immediate impact in the clinical arena is in the evaluation and management of restenosis after percutaneous transluminal coronary angioplasty (PTCA). The overall goal of this research is to develop navigator echo driven magnetic resonance coronary angiography and coronary low measurement into a useful tool for detecting restenosis after PCTA. The specific aims of the study are: 1) Conduct model studies on realistic stenotic coronary flow phantoms with respiratory motion and pulsatile flow to: a) compare 2D and 3D acquisition methods and optimize the most promising approach, b) determine the impact of multiple signal average, high- resolution, navigator echo-driven imaging on the detection of stenose, c) investigate coronary hemodymanics and assess whether stenosis severity can be estimated from post-stenotic signal loss plus flow velocity measurement, d) evaluate the impact of intravascular contrast agents on determining stenosis severity, e) determine the precision and accuracy of an optimized navigator echo-driven MR flow measurement. 2) Assess the accuracy and clinical utility of the optimized MRCA technique for detection of restenosis in post-PTCA patients. Examine 50 patients pre- and post-PTCA with: a) the optimized, multiple signal average, high-resolution, navigator echo-driven MR coronary angiography sequence and compare the images to x-ray angiography, and b) the navigator echo driven MR phase velocity sequence and compare the results to measurements made with intravascular ultrasound.