Advanced Virtual Monoenergetic Technique in Dual-source Dual-energy CT Pulmonary Angiography / 中国医学影像学杂志

ABSTRACT

Purpose To quantitatively evaluate the ability of advanced virtual monoenergetic technique (monoplus) in improving the display of pulmonary arteries with dual-source CT dual-energy pulmonary angiography.Materials and Methods Thirty patients whose CT values in pulmonary artery and its branches were lower than 300 HU in mixed images while image quality was poor in distal branches were enrolled in this study.All these patients underwent dual-source dual-energy (100/Sn140 kVp) CT pulmonary angiography (CTPA) with small amount of contrast medium (30 ml) from September 2016 to December 2016.Non-linear blending images were assigned in group A,100 kVp images from one tube were assigned in group B,and optimized monoenergetic images with low keV monoplus (40+,50+,60+ keV) were assigned in group C,D and E,respectively.CT and SD values of segmental,subsegmental and distal branches were measured,and signal noise ratio (SNR) and contrast noise ratio (CNR) were calculated.Results Among all the 5 groups,CT values of pulmonary artery in group C,D and E were significantly higher than in group A and B (P＜0.05).SNR values of segmental artery in group C were significantly higher than those in group A (P＜0.05).SNR values of subsegmental artery in group C and D were significantly higher than those in group A (P＜0.05).SNR values of segmental and subsegmental pulmonary artery in group C,D and E were all significantly higher than those in group B (P＜0.05).The SNR values of distal branches in group C,D and E were not significantly different from those in group A (P＞0.05),but were significantly higher than those in group B (P＜0.05).CNR values in group C,D and E were not significantly different from those in group A (P＞0.05),but were significantly higher than those in group B (P＜0.05).Conclusion Combined with dual-source dual-energy CT pulmonary angiography,low keV monoplus images can effectively increase CT values of pulmonary artery and clearly display the distal branches.Meanwhile,the image quality is comparable with non-linear blending images,better than that of low tube voltage (100 kVp) images.