The influence of low concentration iodinated contrast agent and low-dose CT scanning technique combined with body mass index on radiation dose and image quality of upper abdominal CT examinations

Abstract

Objective To investigate the influence of double technology (low concentration iodinated contrast agent and low-dose scan) combined with body mass index (BMI) on radiation dose and image quality of contrast-enhanced upper abdominal CT examination. Methods One hundred and twenty patients who received upper abdominal enhanced CT examination were randomly divided into 4 groups: group A1, the iodinated contrast agent iodixanol (270 mg/ml), BMI<18.5 kg/m2 and 80 kVp; group A2, the iodinated contrast agent iodixanol (270 mg/ml), 18.5 kg/m2≤BMI≤24.9 kg/m2 and 100 kVp; group B1, the iodinated contrast agent ioversol (320 mg/ml), <18.5 kg/m2 and 120 kVp; group B2, the iodinated contrast agent ioversol (320 mg/ml), 18.5 kg/m2≤BMI≤24.9 kg/m2 and 120 kVp. Image quality was subjectively scored, the objective parameters (noise, CT values of abdominal aorta and liver parenchyma, contrast noise ratio of abdominal aorta and liver parenchyma) were evaluated and radiation dose was recorded. The differences of the indexes between A1 and B1 groups, A2 and B2 groups were compared with Mann-Whitney U test and pared-samples t test. Results All CT images were good. No images with 4 scores were obtained. No significant difference was found between group A1 and B1, between group A2 and B2 (P>0.05). There was no significant difference in contrast noise ratio of liver parenchyma (P>0.05), while significant differences existed in CT values of abdominal aorta and liver parenchyma, contrast noise ratio of abdominal aorta between group A1 and B1 (P<0.05). Significant differences existed in the parameters above mentioned between group A2 and B2, respectively (P<0.05). Radiation dose was lower in group A1 than in group B1 and in group A2 than in group B2 (P<0.05), respectively. Radiation dose was decreased by 40.1%(0.89/2.22) in group A1 than group B1 while radiation dose decreased by 56.9% (3.02/5.31) in group A2 than group B2. Conclusion According to BMI, the low concentration iodinated contrast agent and low-dose scan CT scanning technology could effectively reduce radiation dose and generate ideal images during the contrast-enhanced upper abdominal CT examination. Key words: Tomography, X-ray computed; Radiation dosage; Contrast media; Body weight