窄窗扫描技术在高心率患者320排CT冠状动脉成像中的应用研究

目的：探讨高心律患者320排CT冠状动脉成像使用前瞻性心电门控窄窗扫描技术对图像质量和辐射剂量的影响。方法80例心率在80~100次/min的患者随机分成观察组和对照组。观察组按R- R间期30％～50％进行前瞻性窄窗扫描3个心动周期，对照组按R- R间期30％～80％进行常规扫描3个心动周期，冠状动脉节段图像质量采用4级评分法评分,辐射剂量值由设备自动计算。结果可评价血管段和优良率两组间差异无统计学意义（P＞0.05）。冠状动脉总节段、右冠状动脉（RCA）、左冠状动脉主干（LM）、左前降支（LAD）和旋支（LCX）的质量评分两组间差异无统计学意义（P＞0.05）。观察组的RCA和LCX与心律波动呈中等程度负相关（r =0.41、0.47）。观察组和对照组平均辐射剂量分别为（7.63±3.29）和（12.85±2.71）mSv，差异有统计学意义（t=1.384，P＜0.05）。结论窄窗扫描技术可应用在心律波动不大的高心率患者，能明显降低辐射剂量而不影响图像质量。

Application of Narrow window scan in coronary 320-MDCT angiography of patients with high heart rate

Objective To investigate the influence of prospective narrow window scan on the image quality and radiation dose of coronary 320- MDCT angiography in patients with high heart rate. Methods 80 patients with heart rate between 80 and 100 bpm were randomly divided into observation group and control group. Prospective scanning with an ECG- gated window of 30- 50%of the R- R interval was performed in observation group and 30- 80% of the R- R interval gated routine scan was acquired in control group in three heartbeats. Coronary artery image was scored using 4- point scale. The radiation dose was automatically calculated by the CT scanner. Results There was no significant difference of assessable coronary segments and excellent rate between two groups. The image quality scores of total coronary segments, RCA, LM, LAD and LCX were not significant difference between two groups. The image quality score of RCA and LCX was negatively correlated with rhythm variation in observation group （r=0.41, 0.47）. The effective dose was significantly lower in observation group than in control group （7.63 ± 3.29） mSv vs.（12.85 ± 2.71）mSv, P〈0.05]. Conclusion Narrow window technology may reduce radiation dose without influencing the image quality of coronary 320- MDCT angiography for patients with high heart rate and less rhythm variation.