Low Concentration Contrast Agent and Low Tube Voltage in Light and Moderate Weight’s Abdominal Contrast-enhanced CT Scan / 中国医学影像学杂志

ABSTRACT

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.