64排螺旋CT低管电压扫描对腹部血管成像病变显示及图像质量的影响

目的：评估低管电压（80 kV）扫描降低腹部CT血管成像检查辐射剂量的作用及对病变显示和图像质量的影响。方法：将36例做腹部CTA检查的患者按照随机数字表法分成试验组和对照组各18例，分别采用管电压80 kV和120 kV，管电流采用自动毫安。比较两组的病变显示、图像质量、腹主动脉CT值及平均辐射剂量，分别对所得的各组数据进行统计学分析。结果：试验组的血管强化值（604.9±132.3）HU明显高于对照组的（378.3±94.3）HU，图像质量评分（3.61±0.16）分明显低于对照组的（4.56±0.12）分，差异均有统计学意义（P〈0.05）。试验组的原始图像噪声高于对照组，但两组信噪比、对比信噪比差异均无统计学意义。试验组血管重建成像图像质量、病变显示与对照组无明显差异，两组图像质量均能满足诊断要求。试验组的容积CT剂量指数（CTDI）、剂量长度乘积（DLP）及有效剂量（ED）较对照组分别降低66.2%、69.7%及69.8%。结论：64排螺旋CT腹部血管成像采用低管电压（80 kV）可降低辐射剂量，病变显示较满意，获得图像可符合临床诊断要求，但原始图像噪声偏高，相关参数及管电流需进一步优化。

The Impact of 64-slice Spiral CT Abdominal Angiography with Low Tube Voltage Scanning on Lesion Visualization and Image Quality

Objective：To evaluate the effect of low tube voltage （80 kV） abdominal CT angiography scanning in reducing the radiation dose and lesion visualization and image quality.Method：36 patients with abdominal CTA examination were randomly divided into the experimental group and the control group,18 cases in each group, respectively by 80 kV and 120 kV tube voltage,with tube current automatic mA.The lesion visualization,image quality,arterial enhancement CT value and the average radiation dose between the two groups were compared.The data obtained were analyzed by statistical analysis.Result：The vascular enhancement CT value of the experimental group was （604.9±132.3）HU,it was significantly higher than （378.3±94.3）HU of control group,the image quality score of experimental group was （3.61±0.16）score,it was significantly lower than （4.56±0.12）score of the control group,the differences were statistically significant（P〈0.05）.The noise of original image was higher than that of control group,but there were no statistically significant differences in SNR and CNR between the two groups.The image quality of vascular reconstruction and lesion visualization could meet the diagnostic requirements,and no significant differences with control group.Volume CT dose index （CTDI）,dose length product （DLP） and the effective dose （ED） in the experimental group decreased by 66.2%,69.7% and 69.8% respectively compared with the control group.Conclusion：The scanning of 64-slice spiral CT abdominal angiography with low tube voltage （80 kV） can reduce X-ray radiation dose.Lesions show satisfactory and the images obtained can consistent with the clinical requirements.The noise of original image is high.The relevant parameters and tube current need further optimization.