The Application Value Of Small Dose Test Technique And Intelligent Tracking Trigger Technique In 128-slice CT Pulmonary Artery Imaging

Purpose:The application value of 128-slice spiral CT small-dose contrast agent mass injection test technique and contrast agent mass injection intelligent tracking automatic trigger technique in pulmonary artery CTA imaging method was studied.To explore the preferred method of pulmonary artery imaging with 128-slice spiral CT.Materials and methods:1、Subjects A total of 62 patients who were clinically suspected to have pulmonary embolism and required PULMONARY artery angiography(CTPA)examination in our hospital from January 2019 to June 2019 were collected.According to the randomization method,they were divided into two groups,group A and Group B,with 31 patients in each group.2、Equipment and scanning methodsPulmonary artery angiography equipment adopts German SIEMENS SOMATOM Definition AS 64 row 128-slice spiral CT scanner and USES German Ulrich double-cylinder high-pressure syringe to inject iohexol(non-ionic)contrast agent through the elbow vein.In group A,low-dose group injection test(Bolus)was used,that is,15 ml contrast agent was first used to test the pulmonary artery circulation time,and then 25 ml contrast agent was used to perform pulmonary artery imaging.In group B,contrast agent intelligent tracking technology was used to automatically trigger the scan(Bolus track)and 40 ml contrast agent was used.The other scanning parameters of the two groups of patients were consistent,which were as follows: tube voltage 120 kV,tube current 250 mAs,and contrast agent concentration350mgI/ml.After the scanning,all the original image data were sent to the MMWP workstation for image post-processing.Image post-processing technologies included:Techniques such as Multi Planar reformatting(MPR),Maximum intensity Projection(MIP)and Volume Rendering(VR).3、Image analysisThe image post-processing and reconstruction of all patients was performed by the same technician who had worked for many years.The images after processing were processed by two imaging diagnostic physicians(associate chief physicians)in our department through double-blind method.The image quality of the two groups was analyzed with the same standard and the corresponding diagnosis was made.4、Statistical analysisSPSS17.0 data processing system was used,and chi-square test was used to determine whether there was a statistically significant difference in gender composition between the two groups.The quantitative data(mean± SD)T test was used to analyze whether there were statistically significant differences in radiation dose and image enhancement CT values between the two groups.The difference in image quality score between the two groups was analyzed by mann-Whitney U non-parametric test.P<0.05 was considered statistically significant.Result:In all pulmonary artery imaging images,there were statistically significant differences in gender,age,body mass index and scan length between the two groups(P >0.05),and there were statistically significant differences in overall image quality scores between the two groups(P<0.05).CT value of pulmonary artery enhancement was high in group B and low in group A(P<0.05).The residual contrast agent in superior vena cava was significantly reduced in group A,and the CT value was also significantly reduced compared with group B,with statistically significant difference(P<0.05).Conclusion:In using the same dose(40 ml)under the condition of contrast medium,two checking methods can meet the 128 layer spiral CT pulmonary artery CTA imaging examination requirements,application of small dose of contrast agent can put the pulmonary artery injection test is more clear,pulmonary vein of artifacts reduction,can more accurately grasp the scan the best time,get better quality of vascular imaging,more suitable for promotion and application in clinic.