| With the development of modern society,a lot of patients have cardiovascular and cerebrovascular diseases,the number is increasing year by year,and the disease has become one of the major diseases affecting the quality of life and health of human beings.CT angiography has been widely used and recognized in clinic because of its simple,fast and non-invasive features.In particular,the application of CTA technology in cervical angiography has its unique advantages in evaluating the degree of cervical vascular stenosis and the nature of plaques,etc.,and has now become an important and preferred procedure for clinical diagnosis.However,the high ionizing radiation generated by routine CTA examination and the potential risk to patients caused by overdosed iodine contrast agents should not be ignored.Therefore,under the premise of meeting the diagnostic requirements,how to reasonably and effectively reduce the radiation dose of the subjects as far as possible,and how to use iodine contrast agent as little as possible to reduce the potential harm to renal function,have become a hot research issue at home and abroad.This dissertation consists of three parts.In the first part,the practical feasibility of replacing 120 kV and FBP scanning protocol with 70 kV low tube voltage and ADMIRE scanning protocol was verified by scanning the standard dose module CATPHAN500.In the second part,the feasibility of 70 kV low tube voltage combined with ADMIRE scanning protocol in neck CTA was demonstrated by scanning patients.In the third part,the feasibility of using 30 m L low contrast agent combined with high-pitch scanning protocol under the condition of low-dose scanning was demonstrated by scanning patients.Through the statistical analysis of the experimental data and the subjective and objective evaluation of the images,we found that in the first part of the module experiment,the image quality was consistent with that of the control group when the m AS was 450-500 in the 70 kV and ADMIRE scanning protocol.However,the CTDIvol values with 70 kV,450 m As and 500 m As were 52.50% and 48.06% lower than those of the control group,respectively.It proved that the 70 kV low tube voltage combined with ADMIRE scanning protocol was theoretically feasible when the tube current was properly increased.In the second part,in the low-tube voltage scanning protocol,there was no statistically significant difference in the subjective and objective evaluation of image quality between the experimental group and the control group.However,compared with the control group,CTDIvol and DLP of the experimental group decreased by 90.6% and 80.1% respectively,which proved that it was feasible to use the 70 kV low tube voltage with ADMIRE scanning protocol in the neck CTA.In the third part,in the scanning protocol of high-pitch combined with low amount of contrast agent,there was no statistically significant difference in the main and objective evaluation of image quality between the two groups.However,the amount of contrast agent used in patients was reduced by 40%,and the CTDIvol value of the control group is higher than that of the experimental group,and the P value is less than 0.05,indicating that it is statistically significant that the CTDIvo of the control group is higher than that of the experimental group.In conclusion,the 70 kV low tube voltage,30 ml low contrast dosage combined with high-pitch and ADMIRE scanning protocol could greatly reduce the radiation dose and contrast agent dosage of patients,which was a new technique worth promoting for cervical CTA scanning. |
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