Automatic Tube Current Regulation Technique for the Evaluation of Aortic Dissection and Postoperative Radiation Dose

Objective To discuss the effect on image quality using a fixed noise figure of Z axis automatic tube current regulation technique in CT angiography of aortic dissection,and reduce radiation dose.Materials and Methods 100 patients with aortic dissection were randomly divided into 2 groups.Group A with fixed tube current scanning technique,tube current 280 mA.Group B,Z axis automatic tube current regulation scanning technique,tube current 100 ～ 350 mA,who were divided into two groups according to BMI,BMI 25 Kg/m2,NI = 10;BMI 25Kg/m2,NI = 12,the other scan parameters were the same.All images were transferred to ADW 4.3 workstation,three dimensional and two dimensional post processing,and machine automatically generated CT dose index(CTDlvol),the corresponding dose length product DLP were recorded.Results Group B did not affect the diagnosis,the radiation dose compared with group A CTDlvol reduced 28.3%,DLP reduced by 30.4%.Mean CTDIvol of group A was(19.13 ± 1.94) mGy;mean DLP was(1205.59 ± 197.12) mGy·cm.In group B BMI 25 Kg/m2,mean CTDIvol was(14.82 ± 2.97) mGy;mean DLP was(887.6 ± 177.51) mGy·cm.In group BMI 25Kg/m2,mean CTDIvol was(12.61 ± 2.17) mGy;mean DLP was(789.86 ± 139.33) mGy·cm,all images were qualified to the diagnostic needs.Conclusion 64 slice spiral CT with a fixed noise index of automatic tube current regulation techniques in CT angiography of aortic dissection can obtain better image quality,and also reduce the radiation dose.