Myocardial Perfusion Imaging and Coronary Angiography Using Low Dose HYPR-CT

描述(申请人提供)：快速旋转、多探测器计算机断层扫描(MDCT)使无创冠状动脉成像发生了革命性的变化。冠状动脉增强CT(CTA)对冠状动脉疾病(CAD)有很高的阴性预测价值，对于CTA中未发现冠状动脉狭窄的有症状患者，无需进行有创冠状动脉造影。然而，当CTA显示狭窄时，对于病变的生理意义可能有很大的不确定性。这项建议的目标是开发一种基于血管造影/心肌灌注MDCT的联合诊断程序，既能检测冠状动脉病变，又能评估它们的生理意义。这将通过两次CT扫描来完成，一次是在休息时获得的，另一次是在药物应激时获得的。使用常规技术的血管造影术/灌注成像术广泛采用的一个主要障碍是需要提供10倍于常规CTA的辐射剂量。这是因为需要进行两次延长扫描，以记录静息和负荷期间的心肌时间-密度曲线。这项建议试图通过使用一种新的重建算法，在不增加常规CTA中目前提供的剂量的情况下，开发一种血管造影/灌注联合检查。高度约束反向投影(HYPR)是一种时间分辨层析成像方法，它利用时空相关性来大大减少每幅图像所需的投影数量。初步研究表明，与传统的心脏CT成像相比，HYPR-CT重建的剂量至少减少了10倍。我们建议开发一种用于血管造影/灌注成像的HYPR-CT算法。该算法将在猪模型中进行开发(目标1)和验证(目标2)。然后，将所得到的算法与心脏患者的放射性核素灌注成像和心导管成像(AIM 3)进行比较。确定冠状动脉狭窄的生理意义对于优化冠心病患者的血运重建决策至关重要。这项研究的成功结论将是一种检测和评估冠状动脉疾病的无创性诊断影像检查。

DESCRIPTION (provided by applicant): Fast-rotation, multi-detector computed tomography (MDCT) has revolutionized noninvasive coronary angiography. Contrast-enhanced CT of the coronary arteries (CTA) has a high negative predictive value for coronary artery disease (CAD), obviating the need for invasive coronary angiography in symptomatic patients in whom coronary stenoses are not detected during CTA. However, when CTA demonstrates a stenosis there can be significant uncertainty regarding the physiological significance of the lesion. The goal of this proposal is the development of a combined angiographic/myocardial-perfusion MDCT-based diagnostic procedure to both detect coronary lesions and also assess their physiological significance. This will be accomplished with two CT scans, one acquired at rest and a second during pharmacological stress. A major obstacle to the widespread adoption of a combined angiographic/perfusion imaging procedure using conventional techniques is the need to deliver a radiation dose on the order of 10 times that of conventional CTA. This is due to the two extended scans necessary to record the myocardial time-density curve at both rest and during stress. This proposal seeks to develop a combined angiographic/perfusion examination without increasing the dose currently delivered during conventional CTA by using a novel reconstruction algorithm. HighlY constrained backPRojection (HYPR) is an approach to time-resolved tomographic imaging that exploits spatio-temporal correlations to greatly reduce the required number of projections per image. Preliminary studies indicate the potential for HYPR-CT reconstruction to provide dose reduction of at least a factor of 10 compared to conventional cardiac CT imaging. We propose to develop a HYPR-CT algorithm for combined angiographic/perfusion imaging. This algorithm will be developed (Aim 1) and validated (Aim 2) in a porcine model. The resulting algorithm will then be compared with radionuclide perfusion imaging and cardiac catheterization imaging in cardiac patients (Aim 3). Determination of the physiological significance of coronary artery stenoses is critical for optimizing revascularization decisions in CAD patients. The successful conclusion of this research will be a noninvasive diagnostic imaging exam for the detection and assessment of coronary artery disease.