Low-dose MSCT pulmonary angiography: low kVp with individual-adapted low tube current

Objective To assess the feasibility of low-dose MDCT pulmonary angiography (MDCTPA) by using low kVp combined with individual-adapted low tube current protocol and noise reduction filter algorithms.Methods Fifty-six consecutively patients with MDCTPA were enrolled in the study.The patients were randomly divided into group A (120 kVp,100 mAs) and group B (100 kVp,individual-adapted tube current about 1.0 mAs/kg).Two series of images were reconstructed in group B:B1 with standard filter algorithms (FC13,B1) and B2 with noise reduction filter algorithms (FC11,B2).The image noise,quality and radiation dose in two groups were compared.Results The CTDIvol,DLP and E of group B were 5.1 mGy,83.3 mGy· cm and 1.4 mSv respectively,which were reduced by 64.3％,66.4％ and 66.7％,respectively (F =32.57,12.32,11.98,P ＜ 0.05) when compared with those in group A.Compared with group A,the image noise in B1 was increased by 118.2％ (t =10.05 P ＜0.05),the central and peripheral SNR and CNR and scores were increased by 51.5％,46.6％,50.8％,45.3％and 20.4％,respectively(t =7.20,6.30,6.58,5.54,8.35,P ＜ 0.05).Compared with B1,the image noise in B2 was reduced by 32.5％ (t =6.12,P ＜0.05),the central and peripheral SNR and CNR and scores were increased by 46.2％,46.2％,45.9％,46.9％ and 18.4％ (t =3.19,3.55,2.95,3.37,5.42,P ＜0.05).Compared with group A,the image noise in B2 group was increased by 47.3％ (t =4.03,P ＜0.05),the central and peripheral SNR and CNR and scores were reduced by 29.1％,21.8％,28.2％,19.6％ and 8.2％(t =4.06,2.82,3.68,2.22,3.02,P＜0.05).Conclusions Keeping effective diagnostic image quality,the protocol with low kVp and individual-adapted low tube current for low-dose MDCT pulmonary angiography would be effective and feasible,and the radiation dose would be significantly reduced. Key words: Low-dose;  Pulmonary artery;  Angiography;  Tomography;  X-ray computed