低剂量64层螺旋CT扫描在下肢静脉造影中的应用

Low-dose 64-slice Spiral CT Scanning in Venography of Lower Limbs

目的:探讨应用低管电流行多层螺旋CT下肢静脉造影(MSCTV)降低辐射剂量的可行性,及对图像质量的影响。方法:选取2011年6月至2012年5月疑似下肢静脉疾病的患者30例,分为I组常规剂量组(120 kV、300 mA)、II组实验组(120 kV、200 mA)、III组实验组(120 kV、100 mA)。分别对各组SNR(信号噪声比)、CNR(对比度噪声比)及辐射剂量进行统计,并由1名资深影像学医师以5分制对图像主观噪声进行评价。结果:I、II、III组的CTDIvol、DLP、E均使用单因素方差检验(one-way ANOVA检验),得出P=0.00,均有统计学意义(P<0.05)。对I、II、III组的信号噪声比(SNR)、对比度噪声比(CNR)均使用单因素方差检验,分别得出F=890.80和F=910.23,P<0.05,均有统计学意义。所有图像均能达到诊断要求。结论:MSCTV使用100 mA所得到的图像能满足诊断要求,同时明显降低对患者的辐射剂量。

Objective To apply low-current multi-slice spiral CT venography of lower extremity（MSCTV） to reduce the radiation dose and the influence on image quality. Methods Totally 30 cases of suspected venous diseases from June 2011 to May 2012 were divided into three groups, including Group I with the conventional dose of 120 kV and 300 mA, Group II with the dose of 120 kV and 200 mA, and Group III with the dose of 120 kV and 100 mA. The SNRs, CNRs and radiation doses of the three groups were summarized, and then the subjective noise of image diagnosis was evaluated by a senior radiologist with 5-point scaling system. Results One-way ANOVA test was used to analyze the CTDIvol, DLP and E of the three groups, and it＇s proved that there were significant differences between them with P=0.00. One-way ANOVA test also was used for SNR and CNR analyses, and it＇s significantly different with F of 890.80 and 910.23 as well as P〈 0.05. All the images could meet the clinical diagnostic requirements. Conolusion MSCTV with 100 mA can meet the clinical diagnostic requirements and reduce the radiation dose to the patient.