Department of Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistrasse 15, 81377, Munich, Germany.
Int J Cardiovasc Imaging. 2013 Feb;29(2):435-42. doi: 10.1007/s10554-012-0080-y. Epub 2012 Jun 20.
CT-based myocardial perfusion imaging (CTP) has been shown to accurately detect myocardial perfusion defects when compared to SPECT. When performing single-phase first-pass stress CTP, timing is of major importance. The aim of this study was to provide guidance for optimal timing of single-phase first-pass stress CTP acquisitions. 16 patients (12 male, age, 69 ± 8 years) with known or suspected coronary artery disease underwent invasive coronary angiography with fractional flow reserve (FFR) measurements using a pressure wire as well as a time-resolved CTP protocol under adenosine stress, performed on a dual-Source CT scanner over a period of 30 s. From the CTP data, time-attenuation curves have been determined both in known ischemic myocardium with a corresponding coronary artery stenosis as proven by a FFR below 0.75 in invasive coronary angiography, as well as in non-ischemic reference myocardium during pharmacological stress. Furthermore, contrast enhancement in the ascending aorta was determined. The time point for an optimal contrast (i.e., difference in Hounsfield Units, HU) between ischemic and normal myocardium was determined. Under pharmacological stress using adenosine, a maximum mean HU difference between ischemic and non-ischemic myocardium (17.7-22.5 HU) was observed 24-32 s after injection of contrast medium. The maximal attenuation difference between normal and ischemic myocardium ranged from 15 to 77 HU in the analyzed patient cohort. When applying a bolus-tracking technique with an automatic contrast detection in the proximal ascending aorta, the optimal time frame for stress CTP was between 8 and 16 s after contrast enhancement in the aorta exceeds 100 HU, or between 7 and 15 s using a threshold of 150 HU. For first-pass CT myocardial perfusion imaging there is a time frame of approximately 8 s for optimal differentiation of ischemic and non-ischemic myocardium, which will be helpful to optimize single-phase CTP scans.
CT 心肌灌注成像（CTP）与 SPECT 相比，已被证实能准确检测心肌灌注缺损。在进行单相首过应激 CTP 时，时间是非常重要的。本研究旨在为单相首过应激 CTP 采集的最佳时间提供指导。16 名（12 名男性，年龄 69±8 岁）患有已知或疑似冠状动脉疾病的患者接受了经皮冠状动脉造影术，术中有压力导丝测量了血流储备分数（FFR），同时还在双源 CT 扫描仪上进行了腺苷应激下的时间分辨 CTP 方案，扫描时长 30 秒。从 CTP 数据中，在经皮冠状动脉造影术显示的 FFR 低于 0.75 的相应冠状动脉狭窄的已知缺血心肌以及药物应激期间的非缺血参考心肌中，确定了时间衰减曲线。此外，还确定了升主动脉的对比增强情况。确定了缺血和正常心肌之间最佳对比（即，亨氏单位差异，HU）的时间点。在使用腺苷进行药物应激时，在注射造影剂后 24-32 秒观察到缺血和非缺血心肌之间的平均 HU 差异最大（17.7-22.5 HU）。在分析的患者队列中，正常和缺血心肌之间的最大衰减差异范围为 15 至 77 HU。当应用近端升主动脉的自动对比检测的团注追踪技术时，主动脉增强超过 100 HU 时，应激 CTP 的最佳时间范围为 8 至 16 秒，或使用 150 HU 阈值时为 7 至 15 秒。对于首过 CT 心肌灌注成像，存在大约 8 秒的时间窗，用于最佳区分缺血和非缺血心肌，这将有助于优化单相 CTP 扫描。
