MAGNETIC RESONANCE CORONARY ANGIOGRAPHY

使用磁共振成像（MRI）作为非侵入性 冠状动脉造影的替代方法 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（MRCA），临床上不用于常规评价 冠心病患者。我们最近发现，使用 作为实时呼吸门控设备的导航回波图像可以 产生冠状动脉图像， 临床竞技场。 然而，也有人担心和质疑， 导航回波门控对图像准确性的影响 得到了 具体来说，导航仪上显示的狭窄 门控图像仍然不确定。 MRCA可能有一个领域， 临床竞技场的直接影响是评价， 经皮冠状动脉腔内成形术后再狭窄的处理 血管成形术（PTCA）。 本研究的总体目标是开发导航回波驱动 磁共振冠状动脉造影和冠状动脉低测量 成为检测PCTA后再狭窄的有用工具。 具体 本研究的目的是：1）对实际狭窄进行模型研究， 具有呼吸运动和脉动流的冠状动脉血流模型： a）比较2D和3D采集方法，并优化最有前途的 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检测狭窄， c）研究冠状动脉血流动力学并评估是否狭窄 严重程度可以通过狭窄后信号丢失加上血流 速度测量，d）评估血管内对比度的影响 e）确定精确度，以及 优化导航回波驱动MR血流测量的准确性。 （二） 评估优化MRCA技术的准确性和临床实用性 用于检测PTCA术后患者的再狭窄。 检查50名患者 PTCA前后：a）优化的多信号平均值， 高分辨率、导航回波驱动MR冠状动脉造影序列 并将图像与X射线血管造影进行比较，以及B）导航回波 驱动MR相速度序列，并将结果与 通过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.