Application of low-dose CT scanning technique in right adrenal vein imaging / 中华放射医学与防护杂志

ABSTRACT

Objective To investgate the application value of low-dose CT scanning in right adrenal vein imaging.Methods A total of 124 patients were enrolled in the study who were suspected as primary aldosteronism and requiring a contrast enhanced CT examination on adrenal glands.Four patients were excluded according to the exclusion criteria,so that the rest 120 patients were divided equally into three groups.Group A was a control group with conventional radiation dose using tube voltage of 120 kV and automatic mA.It was divided into A1,A2 and A3 groups according to arterial phase,portal venous phase and parenchymal phase.Group B was a experimental group with conventional tube voltage of 120 kV and automatic mA,which was divided into B1,B2 and n3 groups according to arterial phase,late arterial phase and portal venous phase.Group C was a low-dose experimental group with a tube voltage of 100 kV and a tube current of 150 mA only in the second phase,the remaining scanning parameters and method were the same as that of group B.The subjective scores of the images of groups A,B and C were statistically analyzed,and the CT values of the right adrenal vein(RAV),the right adrenal gland(RAG),and the fat of anterior abdominal wall at different scan phases were measured.The dose length products (DLP) were recorded and the signal-to-noise ratios (SNR),contrast-to-noise ratios (CNR),effective doses (E) of the three groups were calculated and compared.Results The subjective scores of the two observers were consistent (Kappa value =0.63);the subjective scores of the B2 images were statistically significant (H =7.18,P＜0.05).Difference of subjective scores between B2 and A2was statistically significant (t=-18.03,P＜0.05).The CT values of RAV,SNR,and CNR of the B2 group were higher than those of the A2 group (t=36.99,6.92,9.02,P＜0.05).The radiation dose comparison showed that the effective dose (E) was 45.52％ lower in the low-dose group than the conventional dose group with the statistically significant difference(t =12.19,P＜0.05).Conclusions Using MDCT scanning technique with lower tube voltage and lower tube current of 100 kV-150 mA,the detection rate of right adrenal vein can reach 95％ in the late arterial phase,and the effective dose can be reduced about 45.52％ on the basis of ensuring image quality.