低浓度对比剂低管电压在过轻或适中体重患者腹部CT增强扫描中的应用

摘要

PurposeTo investigate the feasibility of using low concentration contrast agent and low tube voltage in the light and moderate weight's abdominal contrast-enhanced CT scan, in order to find an optimal solution to reduce radiation dose and iodine intake.Materials and Methods Forty patients with light weight whose body mass indexes (BMI) were lower than 20 kg/m2 were randomly divided into group A1 (n=20) and group B1 (n=20). Meanwhile, another 40 patients with moderate weight whose BMI ranged from 20 kg/m2 to 25 kg/m2 were randomly divided into group A2 (n=20) and group B2 (n=20). Low concentration contrast agent and low tube voltage (Visipaque 270 mgI/ml, 100 kV) were used in both group A1 and group A2 in abdominal enhanced CT scan. While both group B1 and group B2 used conventional scan solution (Omnipaque 300 mgI/ml, 120 kV) in abdominal enhanced CT scan. Then the contrast noise ratio (CNR), the image quality score and the effective radiation dose (ED) were compared among the four groups.Results The CNR and image quality score at artery phase and portal phase were neither significantly different between group A1 and group B1, nor between group A2 and group B2 (t=-1.539-0.000,P>0.05). The CNR and image quality score of the liver at artery phase in group B1 were signiifcantly higher than those in group A2 and group B2 (P<0.05).Conclusion The solution of using low concentration contrast agent and low tube voltage in contrast enhanced scan can achieve the same high quality abdominal image with reduced iodine intake and radiation, compared with the application of conventional enhanced scan; BMI has rather great impact on image quality score at arterial phase and little impact on that at portal phase. So it is suggested that the protocol of liver contrast-enhanced CT scan may choose reduction of voltage at portal phase so as to reduce radiation.%目的：探讨低浓度对比剂低管电压在过轻或适中体重患者腹部CT增强扫描中应用的可行性，寻找减少腹部CT增强扫描射线剂量及碘摄取量的最优方案。资料与方法选取体重指数（BMI）<20 kg/m2的40例过轻患者，随机分为A1组和B1组，每组20例；同时选取20 kg/m2≤BMI<25 kg/m2的40例适中体重患者，随机分为A2组和B2组，每组20例。A1组和A2组采用低浓度对比剂低管电压（威视派克270 mgI/ml，管电压100 kV）行腹部CT增强扫描，B1组和B2组采用常规扫描方案（欧乃派克300 mgI/ml，管电压120 kV）行腹部CT增强扫描。比较4组的对比噪声比（CNR）、图像质量评分和有效射线剂量（ED）。结果 A1组和B1组、A2组和B2组动脉期、门静脉期的CNR及图像质量评分比较差异均无统计学意义（t=－1.539~0.000， P>0.05）；B1组动脉期CNR及图像质量评分明显高于A2组和B2组，差异均有统计学意义（P<0.05）。结论低浓度对比剂低管电压扫描方案可以在降低碘摄取量及辐射的同时获得与常规增强扫描同等的腹部图像质量； BMI对肝脏动脉期图像质量影响较大，对门静脉期图像质量影响较小，可考虑在肝脏增强检查协议中选择性降低门静脉期电压以降低辐射。