RESUMO
Objective To evaluate the feasibility of 80 kV tube kilovoltage in aortic artery CT angiography with 256-slice CT. Methods A total of 62 patients undergoing aortic artery CTA were enrolled into this study and divided into conventional tube kilovoltage (120 kV, n = 31 ) and low tube kilovoltage (80 kV, n = 31 ). The signal-to-noise ratio (SNR) , contrast-to-noise ratio (CNR), volume CT dose index (CTDIvol) and effective dose (E) were evaluated, respectively. Results The mean image SNR was ( 35.92 ± 5.04) and ( 33.95 ± 8. 30) for conventional tube kilovoltage and low tube kilovoltage,respectively, with no significant difference (t = 1. 131, P =0. 263). The mean image CNR was (30. 32 ±4.78) and (28.71 ± 7.96 ) for conventional tube kilovoltage and low tube kilovoltage, respectively, with no significant difference ( t = 0. 964, P = 0. 339 ). The average effective dose ( E ) was ( 14. 28 ± 0.96 )mSv and (9. 72± 0. 81 )mSv for conventional tube kilovoltage and low tube kilovoltage, respectively, with significant difference ( t = 20. 12, P ＜ 0. 001 ). Conclusions 80 kV tube kilovoltage aortic artery CTA can reduce radiation dose by 31.9% , and contrast dose 50% ,and maintain image quality compared with 120 kV tube kilovoltage.