摘要
目的:探讨低仟伏值(kV)低辐射量MSCT扫描对泌尿系结石的检出率及对图像质量的影响。方法:将4种单一成分的泌尿系结石108粒放入猪里脊肉内制成结石模型,应用64层螺旋CT对模型进行扫描,扫描的管电压分别为120 kV1、00 kV和80 kV,并与不同的管电流进行组合,层厚为5 mm,层间距为5 mm,螺距为0.984。扫描后的原始数据(5 mm层厚)重建成1.25 mm层厚,使用GE ADW4.3工作站对数据进行处理。测量图像质量的噪声水平,记录X线辐射剂量指标CTDIvol。结果:与对照组120kV-250mAs相比,实验组80kV-150mAs及100kV-50mAs组的噪声SD值仅分别升高7.60%和8.62%,主观评分均为合格,结石检出率为100%,而辐射剂量降低率分别达到81.40%和87.60%。结论:合适的低kV-mAs组合对泌尿系结石的检出率可以达到100%,且明显降低辐射剂量。
Objective：To investigate the detectability of urinary calculi undergoing 64-slice CT scanning with reducing kV and to evaluate the image quality,so as to obtain the optimal scanning program.Methods：The calculi model was made by inserting 108 granules of urinary calculus containing four kinds of simple constituent into pork loin,and then scanned by 64-slice CT.The scanning parameters were as follows：three different dose-groups were chosen according to the fixed kV set 120kV,100kV,80kV;slice thickness and interval 5mm;the pitch is 0.984;the raw data were reconstructed into 1.25mm;all the reconstructed images were transferred to GE ADW4.3 workstation.To evaluate image quality according to different dose-groups and counted the number of detected calculus respectively.The standard deviation（SD） and signal to noise ratio（SNR） of the images were measured.CT dose index volume（CTDIvol） was obtained automatically.Results：120kV^250mAs was set to be the control group.Compared with the control group,80kV^150mAs,100kV^50mAs and 120kV^30mAs noise SD values were only increased by 7.60%,8.62% and 9.07%.The detection rate was 100%,while the radiation dose decreased significantly with the rate reaching 81.40%,87.60% and 87.98% respectively.Conclusion：It can reach 100% for the detection rate of urinary stones using the right combination of low kV-mAs scaning,and significantly reduce the radiation dose.
出处
《放射学实践》
北大核心
2011年第8期810-814,共5页
Radiologic Practice
