Departments of Medicine and Biological Science.
Gunma Prefectural Cardiovascular Center, Maebashi, Gunma.
J Thorac Imaging. 2018 Mar;33(2):97-104. doi: 10.1097/RTI.0000000000000284.
Dual-energy computed tomography (DECT) can be used for visual determination of iodine distribution in the myocardium (iodine image); however, the accuracy and reproducibility of the process remains debatable. Because of the low contrast-to-noise ratio of CT, we hypothesized that quantitative measurement may be more accurate for detecting myocardial ischemia. In this study, we evaluated our quantitative method by comparing it with visual analysis using Tc-tetrofosmin (TF) stress-rest single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) as the reference standard.
Forty-three patients who had a significant stenosis on cardiac rest DECT and had received Tc-TF stress-rest SPECT MPI within 1 month were retrospectively analyzed. The regions of interest were set on iodine images in accordance with the American Heart Association (AHA) 17-segment model (a total of 731 segments). The regions of interest values were divided by the amount of iodine (mg) per unit weight (kg) and defined as perfusion value (perfusion value analysis). All segments were also visually analyzed and receiver operating characteristic curve analysis performed to identify the superior analysis.
The receiver operating characteristic curve analysis showed that perfusion value analysis is significantly superior to visual analysis [the area under the curve: 0.921 (95% confidence interval, 0.860-0.981) versus 0.685 (95% confidence interval, 0.580-0.791), respectively, P<0.05], with 93.8% sensitivity, 99.1% specificity, 98.9% accuracy, 83.3% positive predictive value, and 99.7% negative predictive value (P<0.01).
Quantitative analysis of the iodine image of rest DECT, called perfusion value analysis, is more accurate than visual analysis when compared with Tc-TF SPECT MPI as the reference standard.
双能 CT（DECT）可用于直观判断心肌内碘分布（碘图），但该方法的准确性和可重复性仍存在争议。由于 CT 的低对比噪声比，我们假设定量测量可能更准确地检测心肌缺血。在本研究中，我们通过与 Tc-TF 负荷-静息单光子发射计算机断层扫描（SPECT）心肌灌注成像（MPI）的视觉分析进行比较，评估了我们的定量方法，Tc-TF 负荷-静息 SPECT MPI 是参考标准。
回顾性分析了 43 例心脏休息 DECT 有明显狭窄且在 1 个月内接受 Tc-TF 负荷-静息 SPECT MPI 的患者。按照美国心脏协会（AHA）17 节段模型（共 731 个节段）在碘图上设置感兴趣区。将感兴趣区的值除以单位体重（kg）的碘量（mg），并定义为灌注值（灌注值分析）。还对所有节段进行了视觉分析，并进行了受试者工作特征曲线分析，以确定优势分析。
受试者工作特征曲线分析显示，灌注值分析明显优于视觉分析[曲线下面积：0.921（95%置信区间，0.860-0.981）与 0.685（95%置信区间，0.580-0.791），P<0.05]，灵敏度为 93.8%，特异性为 99.1%，准确性为 98.9%，阳性预测值为 83.3%，阴性预测值为 99.7%（P<0.01）。
与 Tc-TF SPECT MPI 作为参考标准相比，静息 DECT 碘图的定量分析（称为灌注值分析）比视觉分析更准确。
