Quantitative assessment of myocardial perfusion and viability with contrast enhanced MRI

在本研究中，我们继续对首次通过对比增强心肌灌注成像定量评价心肌梗死患者心肌梗死程度的研究。临床对心肌灌注MRI的研究表明，需要改善MR脉冲序列，以减少心脏收缩和次优空间分辨率引起的心内膜下伪影。因此，优化了心脏周期内心肌灌注MRI的心电门控采集延迟时间，以获得心脏收缩和舒张期静息期间的MR图像数据集。此外，采用并行成像方法，将心肌灌注MRI的空间分辨率提高到2 mm以下。在心肌血流灌注定量分析方面，我们改进了血饱和度校正、血液和心肌时间-强度曲线基线检测、…拟合范围的自动确定等方法更多r Patlak Lot分析。有了这些改进，可以准确地确定分布的心肌血流量，提高了重复性，减少了统计差异。对于延迟增强MRI的评价，我们采用并行成像的方法优化了3D延迟增强MR图像采集，并改进了显示心肌梗死的三维分布和跨壁范围的算法。在初步的临床研究中，我们进行了(1)使用Patlak Lot方法定量评估整个左室心肌的心肌血流参数K1，(2)通过用Gd-DTPA的提取分数修正K1值来量化心肌血流量，(3)通过分析静息和ATP负荷心肌灌注MRI来评估心肌灌注储备，以及(4)评估心外膜和心内膜心肌层的心肌血流和心肌灌注储备。这些方法被用来确定缺血性心脏病和肥厚性心肌病的病理生理学。较少

In the current study, we continued our research on quantitative assessment of first-pass contrast enhanced myocardial perfusion MRI and evaluation of extent of infracted myocardium in patient with myocardial infarction. Clinical studies on myocardial perfusion MRI indicated that improvement of the MR pulse sequence is required to reduce subendocardial artifacts caused by cardiac contraction and suboptimal spatial resolution. Consequently, the ECG gated acquisition delay time of myocardial perfusion MRI in the cardiac cycle was optimized so that MR image datasets can be obtained during the systolic and diastolic rest periods of the heart. In addition, spatial resolution of myocardial perfusion MRI was improved to less than 2mm by using a parallel imaging method. As for the quantitative analysis of myocardial perfusion, we have improved the methods of blood saturation correction, baseline detection of blood and myocardial time-intensity curves, automated determination of fitting range fo … More r Patlak lot analysis. With these improvements, distribution myocardial blood flow can be accurately determined with improved reproducibility and reduced statistical variation. As for the assessment of delayed enhanced MRI, we optimized 3D delayed enhanced MR image acquisition by using a parallel imaging method and improved an algorithm to demonstrate three dimensional distribution and transmural extent of myocardial infarction. In the preliminary clinical studies, we performed (1) quantitative assessment of myocardial flow parameter, K1, for the entire left ventricular myocardium by using a Patlak lot method, (2) Quantification of myocardial blood flow by correcting K1 value with extraction fraction of Gd-DTPA, (3) assessment of myocardial perfusion reserve by analyzing rest and ATP-stress myocardial perfusion MRI, and (4) evaluation of myocardial blood flow and myocardial perfusion reserve in epicardial and endocardial myocardial layers. These approaches were used for determining the pathophysiology of ischemic heart disease and hypertrophic cardiomyopathies. Less