RESUMO
Objective:To investigate the feasibility of tube potential of 80 kV combined with personalized contrast agent protocol in carotid artery CT angiography (CTA).Methods:A total of 136 consecutive patients undergoing neck CTA were prospectively enrolled in this study. The patients were randomly divided into Groups A, B, C and D. Tube potential of 100 kV and 15 s contrast agent injection protocol was used for Group A (53 cases) as conventional group, while tube voltage of 80 kV and 10 s contrast agent injection protocol was used for Groups B, C and D as experimental groups, with the contrast agent dosages of 20, 25 and 30 ml used according to the body weights of ≤50 kg(Group B, 20 cases), 50-70 kg (Group C, 38 cases), and 70-90 kg (Group D, 25 cases), respectively. The subjective and objective evaluation results of image quality and the effective doses were compared among the four groups.Results:The effective doses in Groups B, C and D were 1.54±0.91, 1.89±1.08 and 2.14±1.27 mSv, respectively, significantly lower than that in Group A [(5.66±0.56) mSv] ( F=169.34, P<0.05). The image quality of four groups met the requirements of clinical diagnosis. No significant differences were found in subjective evaluation and diagnostic efficacy of the four groups ( P>0.05). The CT number of carotid artery, signal-to-noise ratio and contrast-to-noise ratio of the neck region were significantly lower in Groups B, C and D compared with Group A ( F=14.9, 12.94, 14.43, P<0.05). The CT numbers of target carotid vessel were all higher than 250 HU. Conclusions:The scanning protocol of low tube potential (80 kV) combined with 10 s contrast agent injection protocol could not only reduce the doses of radiation and contrast agent, but also preserve the diagnosis effect. Thus, this scanning protocol was feasible and valuable in clinical application.