RÉSUMÉ
Objective To explore the value of iDose4 iterative reconstruction for coronary CT angiography (CCTA).Methods Totally 124 coronary heart disease patients underwent iDose4 iterative reconstruction and filtered back projection (FBP) reconstruction,of whom,56 ones with BMI not less than 20 kg/m2 were put into No.1 iteration group using 135 kV tube voltage and 68 ones with BMI less than 20 kg/m2 were into No.2 iteration group using 110 kV tube voltage.FBP reconstruction was executed with 110 kV tube voltage.Comparison analyses were carried out on signal noise ratio (SNR),contrast to noise ratio (CNR) and image quality.Results There were significant differences between the values of SNR,radiation dose and image quality in No.1 iteration group and FBP group (P＜0.05).Statistical differences were also found between the values of CNR and radiation dose in No.2 iteration group and FBP group,while there were no obvious differences between the values of SNR and image quality in the above two groups (P＜0.05).Conclusion Low-voltage iDose reconstruction gains advantages in radiation dose and image quality during 64-slice CCTA,and thus is worthy promoting clinically.
RÉSUMÉ
Objective: So far, CT back projection technology is already quite mature, this article is a basic research for CT back projection technology, which uses software method to realize back-projection technology, so that you can have a better under-standing of CT back-projection technology. It uses computer soflware programming to realize computer simulation of CT back-projection reconstruction: algorithm is CT back projection algorithm. While realizing back-projection reconstruction, we can choose a suitable faltering function to process received image data in finquency domain, so as to achieve the purpose of the elimination of simple back-projection arising from star-shaped artifact. Methods: The programming environment uses VC soft-ware platform integrated development environment ODE). It bases on the CT filtering back-projection reconstruction algorithm and develops a PC software of graphic user interface. By choosing the value of the various parameters related to the back-pro-jection, we can obtain different effect of back-projection reconstruction image, so that we can compare the result of different pa-rameters to get important factors which effects CT filter back-projection most. Results: We realize the simulation of image re-construction of standard phantom. The interface is easy, so makes it very convenient for deeper understanding of back-projec-tion reconstruction, at the same time the filtering function based on the frequency domain also partly eliminates the star artifact caused by reconstruction process. The reconstruction image of the standard phantom achieves the desired effect. Conclusions: The software simulation of the back-projectiun reconstruction can show the process of recoustruction clearly. By change the val-ue of the parameters, we can have a better understanding of the reconstruction algorithm, so that we can find more suitable fil-tering function.