Department of Radiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, PR China.
GE Healthcare, Computed Tomography Research Center, Beijing, PR China.
Acad Radiol. 2019 Dec;26(12):1591-1596. doi: 10.1016/j.acra.2019.01.018. Epub 2019 Mar 4.
To demonstrate the improved enhancement degree and uniformity in coronary CT angiography (CCTA) on a 16 cm wide-coverage CT with a new bolus tracking method enabled by free-breathing, in comparison with the conventional breath-holding method.
A total of 200 patients with suspected coronary heart disease were randomly divided into two groups for CCTA: Group A (n = 100, free-breathing) started CCTA with 2.2 seconds delay after the attenuation in aorta reached 250 HU; Group B (n = 100, breath-holding), used the standard protocol of 80 HU threshold and 8.4 seconds delay. Both groups used the contrast dose rate of 25 mgI/kg/s. CT value and standard deviation in aortic sinus (AS), right coronary artery, left anterior descending, left circumflex, and pericardial fat were measured. Contrast-to-noise ratio for vessels was calculated. Two experienced Radiologists independently reviewed image quality using a 5-point scale (1: nondiagnostic-5: excellent).
There was no difference in contrast dose, radiation dose, heart rate, and qualitative image quality between the two groups (all p > 0.05). However, Group A had higher mean enhancement in vessels (404 ± 66 HU) than Group B (321 ± 69 HU), and lower coefficients of variation of CT value in aortic sinus, right coronary artery, left anterior descending, and left circumflex (16.3%, 17.7%, 19.2%, and 20.5% vs 21.5%, 22.3%, 23.6%, and 22.9%, respectively), (all p < 0.05).
A new bolus tracking method enabled by free-breathing in CCTA on a 16 cm wide-coverage CT system increases the enhancement degree and uniformity in coronary arteries, compared with the conventional breath-holding method.
本研究旨在比较 16cm 宽探测器覆盖 CT 采用新的自由呼吸触发方法与传统屏气触发方法行冠状动脉 CT 血管成像（CCTA）时，评估新方法在冠状动脉增强程度和均匀度的改善情况。
200 例疑似冠心病患者随机分为两组行 CCTA：A 组（n=100，自由呼吸），在主动脉强化达 250HU 后 2.2 秒启动扫描；B 组（n=100，屏气），采用 80HU 阈值和 8.4 秒延迟的标准方案。两组均采用 25mgI/kg/s 的对比剂剂量率。测量主动脉窦（AS）、右冠状动脉、左前降支、左旋支和心包脂肪的 CT 值和标准差。计算血管的对比噪声比。两位有经验的放射科医生独立采用 5 分制（1：不可诊断-5：优秀）对图像质量进行评价。
两组间对比剂用量、辐射剂量、心率和定性图像质量无差异（均 P＞0.05）。但 A 组血管的平均强化程度（404±66HU）高于 B 组（321±69HU），AS、右冠状动脉、左前降支和左旋支的 CT 值变异系数（16.3%、17.7%、19.2%和 20.5%比 21.5%、22.3%、23.6%和 22.9%）较低（均 P＜0.05）。
16cm 宽探测器覆盖 CT 系统的自由呼吸触发 CCTA 新方法可增加冠状动脉的增强程度和均匀度，优于传统屏气触发方法。
