Wang Yi-ning, Li Luo, Kong Lin-yan, Wang Zhi-wei, Zhou Kang, Cao Jian, Fan Gong-lian, Zhang Xiao-na, Zhang Zhu-hua, Jin Zheng-yu
Department of Radiology, PUMC Hospital, Beijing 100730, China.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao. 2010 Dec;32(6):597-600. doi: 10.3881/j.issn.1000.503X.2010.06.001.
To evaluate image quality (IQ) and radiation exposure of coronary computed tomographic angiography (CTA) with prospectively electrocardiographic (ECG) triggered high-pitch spiral acquisition using dual source CT.
Totally 75 consecutive patients with a stable heart rate (HR) ≤65 bpm underwent coronary CTA. patients were divided into two groups according to their HR (group A HR≤60 bpm, group B HR >60 bpm to≤65 bpm) . A dual-source CT scanner was used (0.6mm collimation, 0.28s rotation time, 80~100 kV, 370 mAs/rot) . Data acquisition was prospectively ECG-triggered at 60% of the R-R interval with a pitch of 3.4. Images were reconstructed with 75ms temporal resolution, 0.75mm slice thickness and 0.5mm increment. IQ was evaluated using a four-point scale (1=excellent, 4=unevaluable) .
The mean HR and scan time of all patients was (57.2 ± 4.8) bpm and (0.42 ± 0.02) s. Of 1103 coronary artery segments, 934 (84.7%) had an IQ score of 1, 135 (12.2%) score of 2, 18 (1.6%) score of 3,and 16 (1.5%) were rated as unevaluable. There was no significant difference between the two groups in IQ [mean score (1.19 ± 0.52 vs. 1.22 ± 0.55;Z=-1.107,P=0.268) . The rate of evaluable segments showed no significant difference between the two groups (98.5% vs. 98.6%;X2=0.000,P=1.000) . Mean dose-length product of all patients was (67.2 ± 30.4) mGy × cm, mean effective dose was (0.94 ± 0.43) mSv.
In patients with a stable HR of 65 bpm or less, prospectively ECG-triggered high-pitch spiral CT acquisition provides high IQ at low radiation dose.
使用双源CT评估前瞻性心电图（ECG）触发的高螺距螺旋采集的冠状动脉计算机断层血管造影（CTA）的图像质量（IQ）和辐射暴露。
连续75例心率（HR）稳定≤65次/分钟的患者接受冠状动脉CTA检查。根据心率将患者分为两组（A组HR≤60次/分钟，B组HR>60次/分钟至≤65次/分钟）。使用双源CT扫描仪（准直0.6mm，旋转时间0.28秒，80~100kV，370mAs/旋转）。数据采集在前瞻性ECG触发下于R-R间期的60%进行，螺距为3.4。图像以75ms的时间分辨率、0.75mm的层厚和0.5mm的层间距重建。使用四点量表评估IQ（1=优秀，4=不可评估）。
所有患者的平均心率和扫描时间分别为（57.2±4.8）次/分钟和（0.42±0.02）秒。在1103个冠状动脉节段中，934个（84.7%）的IQ评分为1，135个（12.2%）评分为2，18个（1.6%）评分为3，16个（1.5%）被评为不可评估。两组之间的IQ无显著差异[平均评分（1.19±0.52对1.22±0.55；Z=-1.107，P=0.268）]。可评估节段的比例在两组之间无显著差异（98.5%对98.6%；X2=0.000，P=1.000）。所有患者的平均剂量长度乘积为（67.2±30.4）mGy×cm，平均有效剂量为（0.94±0.43）mSv。
在心率稳定在65次/分钟及以下的患者中，前瞻性ECG触发的高螺距螺旋CT采集在低辐射剂量下可提供高图像质量。
