| Objectives To evaluate the effect of two different scan modes on the quality of image,radiation dose,total scan time and dose of contrast agent in the combined examination of chest pain with Revolution CT.,to provide theoretical basis for “Double low”mode scanning in patients with acute chest pain.Methods To collect patients who complained of chest pain from October 2019 to December 2020 and were clinically diagnosed as suspected “Chest pain triad”and underwent computed tomography angiography(CTA),according to the exclusion criteria,60 patients were included.All patients underwent one-stop CTA combined scan of pulmonary,coronary and aortic arteries.According to the tube voltage(100kv,80kv)and scanning sequence(pulmonary artery-thoracic aorta-coronary artery),traditional scanning mode(pulmonary artery-coronary artery-thoracic aorta),the subjects were randomly divided into four groups: Group A,Group B,Group C,Group D,15 cases in each group.The voltage of a group tube is set to 100 kv,the optimized scanning mode is adopted;the voltage of B group tube is set to 100 kv,the traditional scanning mode is adopted;the voltage of C group tube is set to 80 kv,the optimized scanning mode is adopted;the voltage of D group tube is set to 80 kv,the traditional scanning mode is adopted.The other scanning parameters of each group were the same.The level of tracheal Carina was used as the monitoring level,and the area of interest was located at the trunk of pulmonary artery.The average CT value of the same section of each segment of blood vessel and the CT value of right ventricle and right atrium were measured and compared in four groups,and the total examination time and the amount of contrast agent used in each group were compared,the differences of image contrast noise ratio(CNR),noise,radiation dose and subjective evaluation in each group were compared,P< 0.05 was statistically significant.Results The basic condition and the main pathological changes of the four groups were analyzed,and the age,sex,BMI,heart rate at rest and so on were compared in the discussion of adjusting the sequence of chest pain triple scan,the total scanning time of the four groups was(17.97 ± 0.59)s in Group A,(26.85 ± 0.72)s in Group B and(18.12 ±0.55)s in Group C,in group D(26.92 ± 0.76)s,the length of time in Group A and Group C using optimized scanning mode was significantly shorter than that in Group B and Group D using traditional scanning mode(P<0.05),group A(79.22±2.12)ml,group B(104.11±1.79)ml,Group C(78.82±1.80)ml,group D(103.48±1.24)ml,Group A and group C used less contrast agent than Group B and Group D(P<0.05).The CT values of pulmonary artery,coronary artery and thoracic aorta in the four groups were significantly different(P<0.05),while the CNR values of pulmonary artery,thoracic aorta and coronary artery in the four groups were not significantly different(P>0.05),there were significant differences in CNR of proximal,middle and distal segment of LAD,proximal and distal segment of LCX(P>0.05).The radiation dose using 100 kv tube voltage in group A and group B was higher than that using 80 kv tube voltage in Group C and Group D,there was significant difference among the four groups(P<0.05).There was no significant difference in subjective score between pulmonary artery and thoracic aorta(P>0.05),there was significant difference in subjective score of coronary artery in four groups(P<0.05),and there was no significant difference in noise value of images in four groups(P>0.05).Conclusions 1 The scan sequence of pulmonary artery-thoracic aorta-coronary artery can reduce the dose of contrast media,shorten the scan time and save valuable time for patients with acute chest pain At the same time,it can reduce the influence of the accumulation of contrast media in right atrium and right ventricle on coronary artery,improve the image quality of coronary artery,and provide high-quality image data for radiologists.2 The100 kv and 80 kv tube voltage can be used to complete the triple examination of chest pain and reduce the radiation dose without affecting the image quality.Figure 5;Table 6;Reference 71... |
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