Fujimoto Shinichiro, Giannopoulos Andreas A, Kumamaru Kanako K, Matsumori Rie, Tang Anji, Kato Etsuro, Kawaguchi Yuko, Takamura Kazuhisa, Miyauchi Katsumi, Daida Hiroyuki, Rybicki Frank J, Mitsouras Dimitris
1 Department of Cardiovascular Medicine, Juntendo University Graduate School of Medicine , Tokyo , Japan.
2 Department of Radiology, Applied Imaging Science Laboratory, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA.
Br J Radiol. 2018 Jul;91(1087):20180043. doi: 10.1259/bjr.20180043. Epub 2018 Apr 12.
Results of the use of the transluminal attenuation gradient (TAG) at coronary CT angiography (CCTA) to predict hemodynamically significant disease vary widely. This study tested whether diagnostic performance of TAG to predict fractional flow reserve (FFR) ≤ 0.8 is improved when applied separately to subsets of coronary arteries that carry similar physiological flow.
28 patients with 64 × 0.5 mm CCTA and invasive FFR in ≥1 major coronary artery were retrospectively evaluated. Two readers assessed TAG in each artery. The receiver operating characteristic (ROC) area under the curve (AUC) was used to assess the diagnostic performance of TAG to detect hemodynamically significant disease following a clinical use rule [negative: FFR > 0.8 or ≤ 25% diameter stenosis (DS) at invasive catheter angiography; positive: FFR ≤ 0.8 or ≥ 90% DS at invasive catheter angiography]. ROC AUC was compared for all arteries pooled together, vs separately for arteries carrying similar physiological flow (Group 1: all left anterior descending plus right-dominant left circumflex; Group 2: right-dominant RCA plus left/co-dominant left circumflex).
Of the 84 arteries, 30 had FFR measurements, 30 had ≤25% DS and 13 had ≥90% DS. 11 arteries with 26-89% DS and no FFR measurement were excluded. TAG interobserver reproducibility was excellent (Pearson r = 0.954, Bland-Altman bias: 0.224 Hounsfield unit cm). ROC AUC to detect hemodynamically significant disease was higher when considering arteries separately (Group 1 AUC = 0.841, p = 0.039; Group 2 AUC = 0.840, p = 0.188), than when pooling all arteries together (AUC = 0.661).
Incorporating information on the physiology of coronary flow via the particular vessel interrogated and coronary dominance may improve the accuracy of TAG, a simple measurement that can be quickly performed at the time of CCTA interpretation to detect hemodynamically significant stenosis in individual coronary arteries. Advances in knowledge: The interpretation of TAG may benefit by incorporating information regarding which coronary artery is being interrogated.
在冠状动脉CT血管造影（CCTA）中使用腔内衰减梯度（TAG）预测血流动力学显著病变的结果差异很大。本研究测试了将TAG单独应用于具有相似生理血流的冠状动脉亚组时，其预测血流储备分数（FFR）≤0.8的诊断性能是否得到改善。
回顾性评估28例接受64×0.5mm CCTA检查且至少1支主要冠状动脉进行了有创FFR检测的患者。两名阅片者评估每支动脉的TAG。曲线下接受者操作特征（ROC）面积（AUC）用于评估TAG按照临床应用规则检测血流动力学显著病变的诊断性能[阴性：有创导管血管造影时FFR>0.8或直径狭窄（DS）≤25%；阳性：有创导管血管造影时FFR≤0.8或DS≥90%]。比较所有动脉汇总后的ROC AUC，与具有相似生理血流的动脉分别计算的ROC AUC（第1组：所有左前降支加右优势型左旋支；第2组：右优势型右冠状动脉加左/共优势型左旋支）。
84支动脉中，30支进行了FFR测量，30支DS≤25%，13支DS≥90%。排除11支DS为26%-89%且未进行FFR测量的动脉。TAG的观察者间重复性极佳（Pearson r=0.954，Bland-Altman偏差：0.224亨氏单位/cm）。单独考虑动脉时，检测血流动力学显著病变的ROC AUC更高（第1组AUC=0.841，p=0.039；第2组AUC=0.840，p=0.188），高于所有动脉汇总时（AUC=0.661）。
通过特定的受检血管和冠状动脉优势情况纳入冠状动脉血流生理学信息，可能会提高TAG的准确性，TAG是一种简单的测量方法，可在CCTA解读时快速进行，以检测个体冠状动脉中血流动力学显著的狭窄。知识进展：纳入关于正在检测哪支冠状动脉的信息可能有助于TAG的解读。
