Division of Cardiology, University of Ottawa Heart Institute, Ottawa, ON, Canada.
Circ Cardiovasc Imaging. 2020 Feb;13(2):e009769. doi: 10.1161/CIRCIMAGING.119.009769. Epub 2020 Feb 11.
Measurement of myocardial blood flow (MBF) with single photon emission computed tomography (SPECT) is feasible using cardiac cameras with solid-state detectors. SPECT MBF has been shown to be accurate when compared with positron emission tomography MBF measured in the same patients. However, the value of a test result applied to an individual patient depends strongly on the precision or repeatability of the test. The purpose of our study is to measure the precision of SPECT MBF measurements using Tc-tetrofosmin and a solid-state cardiac camera.
SPECT MBF was measured in 30 patients and repeated at a mean interval of 18 days. MBF was evaluated from images with and without attenuation correction based on a separately acquired CT scan. The dynamic images were processed independently by 2 operators using in-house kinetic analysis software that applied a 1-tissue-compartment model. The K1 rate constant was converted to MBF using previously determined extraction fraction corrections. Correction for patient body motion was applied manually.
The average coefficient of variation (COV) in the differences between the 2 MBF measurements was between 28% and 31%. The interobserver COV was between 11% and 15%. Myocardial flow reserve is the ratio of MBF measured at stress and rest, and the COV is correspondingly higher. The COV for the difference in repeated myocardial flow reserve was 33% to 38%, whereas the interobserver COV was 13% to 22%.
The COV for the difference in SPECT MBF measurements obtained on separate days is 28% to 31%. The corresponding COV for myocardial flow reserve is 33% to 38%.
使用固态探测器的心脏相机进行单光子发射计算机断层扫描（SPECT）可以实现心肌血流（MBF）的测量。与同一患者中测量的正电子发射断层扫描 MBF 相比，SPECT MBF 已被证明是准确的。然而，测试结果对个体患者的价值取决于测试的精度或可重复性。我们的研究目的是使用 Tc-四氮茂和固态心脏相机测量 SPECT MBF 的精度。
对 30 例患者进行 SPECT MBF 测量，平均间隔 18 天重复测量。根据单独采集的 CT 扫描，对有和无衰减校正的图像进行 MBF 评估。动态图像由 2 名操作人员使用内部动力学分析软件独立处理，该软件应用了 1 组织室模型。使用先前确定的提取分数校正将 K1 速率常数转换为 MBF。手动应用患者身体运动的校正。
两次 MBF 测量值之间差异的平均变异系数（COV）在 28%至 31%之间。观察者间的 COV 在 11%至 15%之间。心肌血流储备是在应激和休息时测量的 MBF 的比值，相应的 COV 更高。重复心肌血流储备差异的 COV 为 33%至 38%，而观察者间的 COV 为 13%至 22%。
在不同天数获得的 SPECT MBF 测量值之间的 COV 为 28%至 31%。相应的心肌血流储备的 COV 为 33%至 38%。
