Division of Cardiology, Vancouver General Hospital, 2775 Laurel Street, Vancouver, BC, V5Z 1M9, Canada.
Division of Cardiology, Vancouver General Hospital, 2775 Laurel Street, Vancouver, BC, V5Z 1M9, Canada.
J Cardiovasc Comput Tomogr. 2019 Mar-Apr;13(2):86-91. doi: 10.1016/j.jcct.2019.01.020. Epub 2019 Jan 30.
Myocardial CT perfusion imaging with dual energy (DE-CTP) can produce myocardial iodine perfusion maps. This study evaluated the accuracy of first pass myocardial iodine concentration in DE-CTP compared to CT derived dynamic myocardial blood flow (MBF) to determine regional myocardial ischemia in an animal model of coronary stenosis using invasive Fractional Flow Reserve (FFR).
Seven anaesthetised pigs (mean weight 51 ± 4 kg) had a graded coronary artery stenosis produced in six vessels (plus one control animal) using a methacrylate plug with FFR recorded in the target artery (ischemia = FFR<0.80). During adenosine vasodilation, dynamic myocardial CTP and DE-CTP imaging was performed. Using vendor supplied applications, matching regions of interest (ROIs) were drawn in myocardial segments supplied by the target coronary artery to compare the two techniques.
FFR correlated strongly to MBF (r = 0.81) and modestly to myocardial iodine concentration (r = 0.65) and myocardial CT attenuation (r = 0.62) (p < 0.0001 each). The correlation to FFR was stronger using relative ratios (absolute value/reference value of normal segments) than absolute values for MBF (r = 0.86), myocardial iodine concentration (r = 0.80) and CT number (r = 0.79) (p < 0.0001 each). Comparing normal and ischaemic territories there were significant differences in MBF (96 ± 14 vs. 27 ± 18 ml/100 ml of tissue/min, p < 0.0001), myocardial iodine concentration (3.5 ± 1 vs. 1.0 ± 0.7 mg/ml, p < 0.0001) and myocardial CT number (89 ± 9 vs. 73 ± 14 HU, p = 0.002). Myocardial iodine concentration had 91% sensitivity and 98% specificity for detecting FFR <0.8.
Quantified myocardial iodine content from first pass DE-CTP correlates with CT derived myocardial blood flow and FFR and accurately discriminates ischemic territories in a porcine model. The accuracy and utility of myocardial iodine content in DE-CTP warrants further investigation in a clinical population with FFR as a reference standard.
双能 CT 灌注成像（DE-CTP）可生成心肌碘灌注图。本研究通过使用有创性血流储备分数（FFR）评估冠状动脉狭窄动物模型中首次通过心肌碘浓度在 DE-CTP 中的准确性，以确定 CT 衍生的动态心肌血流（MBF）来确定局部心肌缺血。
在 7 只麻醉猪（平均体重 51±4kg）中，使用甲基丙烯酸酯塞在 6 个血管中（加一个对照动物）逐渐形成冠状动脉狭窄，并在目标血管中记录 FFR（缺血=FFR<0.80）。在腺苷扩张期间，进行动态心肌 CTP 和 DE-CTP 成像。使用供应商提供的应用程序，在由目标冠状动脉供应的心肌节段中绘制匹配的感兴趣区域（ROI），以比较两种技术。
FFR 与 MBF 密切相关（r=0.81），与心肌碘浓度（r=0.65）和心肌 CT 衰减（r=0.62）中度相关（均<0.0001）。使用相对比率（正常节段的绝对值/参考值）与 MBF（r=0.86）、心肌碘浓度（r=0.80）和 CT 数（r=0.79）的绝对值相比，与 FFR 的相关性更强（均<0.0001）。比较正常和缺血区域，MBF（96±14 与 27±18 ml/100 ml 组织/分钟，p<0.0001）、心肌碘浓度（3.5±1 与 1.0±0.7 mg/ml，p<0.0001）和心肌 CT 数（89±9 与 73±14 HU，p=0.002）有显著差异。心肌碘浓度检测 FFR<0.8 时，其敏感性为 91%，特异性为 98%。
首次通过 DE-CTP 的定量心肌碘含量与 CT 衍生的 MBF 和 FFR 相关，并且可以准确地区分猪模型中的缺血区域。DE-CTP 中心肌碘含量的准确性和实用性需要进一步研究，以 FFR 为参考标准，在临床人群中进行研究。
