Comparison Of Two Scanning Methods Of Pulmonary Artery CTA And Analysis Of Factors Related To Peak Time

Objective:1.To observe and evaluate the advantages and disadvantages of test-bolus and bolus-tracking CTPA imaging methods in dual-source CT.2.The peak time of CTPA in dual-source CT and related individual factors were investigated by low-dose test.Material and methods:1.One hundred and sixty patients with suspected pulmonary embolism and CTPA were randomly divided into two groups.Group A determined the scanning delay time according to Test Bolus.Group B performed triggering scan according to Bolus tracking.Two radiologists with many years of experience scored the image quality of the two groups.CT value and scan radiation dose were measured and recorded.Radiation dose and Image quality were compared between the two groups using rank-sum test and t-test of two independent samples.2.The test bolus technique was used in Group A patients.The obtained image data were loaded into Dyn Eva software to analyze the time density curve of main pulmonary artery.Meanwhile,we need to ana lyse the relationships between cardiac output,systolic pressure,diastolic pressure,sex,age,height,weight,body mass index and peak time of contrast agent in main pulmonary artery.The method we use is multivariate analysis.Results:1.In subjective evaluation,the difference of image quality between the two trigger methods was statistically significant（P<0.05）.The CT values of superior vena cava,ascending aorta,left atrium and the difference between pulmonary artery and pulmonary vein were significantly different between the two groups（P<0.05）.There was no significant difference in radiation dose between the two trigger modes during pulmonary artery scanning（P>0.05）,however,the difference was statistically significant in the monitoring stage（P<0.05）.2.There was no significant correlation between peak time and systolic pressure,diastolic pressure,body mass index,height,sex,age.There was a negative correlation between cardiac output,and time to peak（r=-0.313,P<0.01）.Conclusion:In the two scanning schemes（low-dose test and intelligent tracking trigger）,the low-dose test can better reduce the superior vena cava sclerosis artifact and lower enhancement of the pulmonary veins and ascending aorta to let pulmonary artery shown more clearly and has higher image quality.However,the radiation dose of the low-dose test method is slightly higher than that of the intelligent tracking trigger method.In CTA imaging of pulmonary artery,test-bolus technique and related statistical analysis showed that peak time was negatively correlated with cardiac output.