The Study Of Low Dose Coronary Angiography With640-slice Volume CT

Objective: This article aimed to investigate the feasibility of low dose coronary CTangiography (CCTA) combined use automatic exposure control and adaptive iterative dosereduction technique with640-slice volume CT.Methods:Seven normal Tibet pigs whose weight ranged22-30(24.43±3.047)kg wereinvolved after anesthesia. All the pigs were underwent CCTA with640-slice volume CTfor three times with different tube current and reconstruction algorithm, the acquired dataof which were grouped as A, B, C. Group A:250mA with FBP reconstruction; Group B:standard deviation (SD)30auto exposure control (AEC) with FBP reconstruction; GroupC: SD30AEC with AIDR reconstruction. Image noise, SNR and CNR of proximal, middleand distal segments of coronary artery were measured as objective evaluation while3-pointscale was used for image quality evaluation. Compared the result each other among thethree groups. And then compared the CT dose index, the dose length product and theeffective radiation dose among the three groups.Results:(1)The mean radiation dose of Group C was (0.89±0.30)mSv, which was83%and40%lower than Group A (5.23±0.42)mSv and Group B (1.47±0.49)mSv, whileGroup B was72%lower than Group A,respectively.(k=0.014).(2)No statisticallysignificant difference was found between Group C and Group A in terms of subjectiveimage quality scoring, while there was statistical significant difference between Group Aand Group B, between Group C and Group B.(3)The mean noise of Group B was(76.62±34.28), which was52%higher than Group C(36.87±29.58).There was no statisticallysignificant difference on image noise between Group C and Group A(p﹥0.05),whilestatistically significant difference was found between Group C and Group B(p＜0.05).(4)No significant difference was found in the three groups in terms of SNR and CNR inproximal CAsegments.Conclusion:.(1) Although it can reduce the radiation dose using AEC technology with640-slice volume CT, but also with the decreased image quality,so in the use of AECtechnology,the iterative algorithm should be considered at the same time.(2)640-slice volume CT combined use of AEC and AIDR technology can meet the diagnosis inguarantee the quality of the image while reduce the radiation dose.