摘要
目的:评估自动毫安低管电压64层螺旋CT扫描对头颈部血管造影图像质量及辐射剂量的影响。方法:收集60例行头颈CTA检查的患者。随机分为4组,Ⅰ组管电压为100kV,噪声指数(NI)为20;Ⅱ组管电压为120kV,NI为20;Ⅲ组管电压为100kV,NI为10;Ⅳ组管电压为120kV,NI为10。使用64层螺旋CT进行扫描。定量和定性分析图像质量,并记录辐射剂量。统计学分析采用单因素方差分析,P<0.05为差异有统计学意义。结果:动脉CT值、图像噪声、背景信号的结果有统计学差异(P<0.05)。在NI相同时,kV值降低,动脉CT值升高,噪声升高,背景也升高;而信噪比(SNR)和对比噪声比(CNR)无统计学差异。NI相同时,管电压为120kV组与100kV组的图像质量评分无差别,管电压相同时,NI=10组图像质量优于NI=20组。结论:自动毫安低剂量CT扫描技术可以在明显降低辐射剂量的同时确保图像质量,管电压为100kV、NI为20可以满足临床诊断需要。
Objective： To evaluate the effect of auto-mA low-kV CT scanning on image quality and radiation dose for the head and neck CT angiography. Methods： This prospective study was performed in 60 patients needed head and neck CTA. Patients were randomly divided into four groups： group I kV=100, NI=20; group II ： kV=120, NI=20; group III： kV=100, NI=10; group IV kV=120, NI=10. Images were obtained with 64 mutislice spiral CT scanner（GE LightSpeed VCT XT）. The other parameters include： slice thickness 0.625mm, pitch 0.984, 0.4s/rot, FOV 22cm, matrix 512＊512, standard algorithm. Images were all transmitted to off-line workstation （GE AW4.4） and volume rendering （VR）, muhiplanar reformat （MPR） were reformatted for further scoring. Quantitative and qualitative analysis of image were performed, and radiation dose was recorded. The methods of statistics analysis were ANOVA, and P〈0.05 represented the significant difference. Results： The differences between CT value, noise and background signal were significant. In the same NI, with decreasement of kV, CT value, noise, and background signal were all increased. However, SNR and CNR had no significant difference,. In the same NI, there was no significant difference among the image quality of four groups. In the same kV, the image quality of two NI=10 groups was obvious bettter than the other two NI=20 groups. Conclusion： Auto-mA low-dose CT scanning can reduce radiation dose significantly, meanwhile ensure the image quality. Scan protocol of kV=100 and NI= 20 can guarantee the imaging quality of diagnostic purpose.
出处
《天津医科大学学报》
2010年第2期322-325,共4页
Journal of Tianjin Medical University
