Application value of " one-stop" scanning of coronary and head and neck CTA using low tube voltage / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the value of "one-stop" scanning of coronary and head and neck CTA in patients with normal body mass index (18 kg/m2 ≤ BMI ≤ 25 kg/m2) using low tube voltage (80 kVp).Methods In a retrospective analysis 80 patients with normal body mass index who had completed "one-stop" scanning of coronary and head and neck CTA were divided into A and B groups according to different scanning method,and 40 consecutive cases were selected in each group.Scanning parameters of group A and group B were tube voltage 80 kV,coronary CTA tube current 550 mA,head and neck CTA tube current 500 mA,and tube voltage 100 kV,coronary CTA tube current 450 mA,head and neck CTA tube current 400 mA separately.Subjective evaluation and objective evaluation were performed on the image quality of the two groups.CT values of coronary artery and head and neck CTA trunk branch vessel,contrast-to-noise ratio (CNR),image noise (SD) and effective dose between the two groups were compared.Results The image quality of both groups met the diagnostic requirements,and there was no statistically significant difference in subjective scores between two groups (P＞0.05).The CT values of coronary arteries,the main branches of the head and neck (the common carotid artery,the internal carotid artery) and SD of head and neck CTA were significantly different between two groups (t=4.737,6.552,3.359,2.165,2.685,4.617,P＜0.05).There was no statistically significant difference in SD of coronary CTA,CT values and CNR between head and neck vessels (middle cerebral artery) in group A and group B (P＞0.05).The effective dose of coronary CTA in group A (1.16±0.20) mSy was reduced by 51.1％ than that in group B (2.37±0.77) mSv.The effective dose of head and neck CTA in group A (0.37±0.03) mSv was reduced by 47.9％ than that in group B (0.71 ± 0.17) mSv.Conclusions The image quality with subjective evaluation met the diagnostic requirements when using a low-tube voltage for "one-stop"scanning of coronary and head and neck CTA.The CNR values were basically consistent with the conventional scanning method,and the patient effective dose was reduced by about 50％.