Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.
JACC Cardiovasc Imaging. 2016 Sep;9(9):1074-1083. doi: 10.1016/j.jcmg.2015.10.028. Epub 2016 Jun 29.
The goal of this study was to assess the effect of coronary artery diameter on luminal attenuation and the correlation between the transluminal attenuation gradient (TAG) and transluminal diameter gradient (TDG) on computed tomography (CT) coronary angiography.
Recent studies have reported promising results of TAG in detecting significant stenosis. However, because of the intrinsic nature of CT reconstruction algorithms, luminal attenuation may be affected by vessel diameter.
In this 3-part study, phantom simulating vessels of various diameters immersed in different contrast mixtures were scanned, and intraluminal attenuations were measured. In addition, dynamic volume CT scanning was performed in 3 mongrel dogs (untreated, a stenosis model, and an occlusion model) using 320-row area detector computed tomography and intraluminal attenuations, and TAGs were calculated at each temporal scan and compared. In a separate clinical study, TAGs and TDGs of 152 coronary arteries from 62 patients who underwent 320-row area detector computed tomography coronary angiography and invasive angiography were measured and compared.
Intraluminal attenuation of phantom vessels gradually decreased along with a decrease in diameter. Animal studies revealed that the peak attenuation of distal smaller coronary arteries did not reach that of proximal larger coronary arteries: 55.2% to 78.1% peak attenuation of proximal coronary arteries. No differences in TAG were found between stenotic and normal left circumflex arteries at temporal scans (all, p > 0.05). The clinical study demonstrated significant correlation between TAG and TDG (r = 0.580; p < 0.0001).
Intraluminal attenuation was shown to decrease with diminution of vessel diameters. In addition, TAG exhibited a significant correlation with TDG, implying that TAG may be a secondary result because of differences in diameters.
本研究旨在评估冠状动脉直径对管腔衰减的影响，以及计算机断层扫描（CT）冠状动脉成像中透壁衰减梯度（TAG）与透壁直径梯度（TDG）之间的相关性。
最近的研究报告了 TAG 检测显著狭窄的有希望的结果。然而，由于 CT 重建算法的固有性质，管腔衰减可能会受到血管直径的影响。
在这项三部分研究中，模拟不同直径血管的体模浸入不同的对比混合物中进行扫描，并测量管腔内衰减。此外，使用 320 排面积探测器 CT 对 3 只杂种犬（未治疗、狭窄模型和闭塞模型）进行动态容积 CT 扫描，并在每个时间扫描时计算 TAG 并进行比较。在另一项临床研究中，对 62 例接受 320 排面积探测器 CT 冠状动脉造影和有创血管造影的患者的 152 条冠状动脉的 TAG 和 TDG 进行了测量和比较。
随着直径的减小，体模血管的管腔内衰减逐渐降低。动物研究表明，较小的远端冠状动脉的峰值衰减未达到较大的近端冠状动脉的峰值衰减：近端冠状动脉的峰值衰减为 55.2%至 78.1%。在时间扫描时，狭窄和正常左回旋支之间的 TAG 没有差异（均，p > 0.05）。临床研究表明，TAG 与 TDG 之间存在显著相关性（r=0.580；p<0.0001）。
管腔衰减随着血管直径的减小而降低。此外，TAG 与 TDG 之间存在显著相关性，这表明 TAG 可能是由于直径差异引起的次要结果。
