• Chun-Ling Ma, Xiao-Xia Chen, Yu-Xin Lei, Xi-Rong Zhang, Yong-Jun Jia, Xin Tian, and Qian Tian.
• Department of Radiology, Affiliated Hospital of Shaanxi University of Traditional Chinese Medicine, Xianyang, Shaanxi, People's Republic of China.
• Br J Radiol. 2016 Jun 1; 89 (1062): 20151022.

ObjectiveTo evaluate the clinical value of dual-energy spectral CT with adaptive statistical iterative reconstruction (ASiR) for reducing contrast medium dose in CT portal venography (CTPV).MethodsThis prospective study was institutional review board-approved, and written informed consent was obtained from all patients. 50 patients undergoing abdominal CT were randomized to 2 groups: Group A (n = 25), using spectral CT and 350 mgI kg(-1) contrast injection protocol; Group B (n = 25), using standard 120 kVp and 500 mgI kg(-1) contrast. Spectral CT images at 60 keV and standard 120-kVp images were both reconstructed with 50% ASiR. CT number and contrast-to-noise ratio (CNR) for intrahepatic and extrahepatic portal veins were measured. The maximum intensity projection (MIP) and volume-rendering (VR) images were used for subjective evaluation. These two kinds of results were statistically analyzed.ResultsCNR values for the intrahepatic portal vein of the 60-keV spectral images (4.2 ± 1.1) were higher than those of 120-kVp images (3.0 ± 2.1) (p = 0.03) and were the same for the extrahepatic portal vein (5.9 ± 1.4 vs 5.9 ± 1.6, p = 0.90). The portal vein and left and right branches in the 60-keV spectral images had higher CT number and lower standard deviation than the 120-kVp images (p < 0.05). Radiation dose (dose-length product and effective dose) and subjective image quality were similar for the two groups, while the spectral CT group required 25% less iodine dose (23.1 ± 3.2 g vs 30.5 ± 5.0 g).ConclusionThe 60-keV spectral CT images with ASiR allow 25% reduction in the iodine dose while providing better or equal image quality as the standard 120-kVp images in portal venography with comparable radiation dose.Advances In KnowledgeCompared with conventional 120-kVp CT, the use of 60-keV spectral CT images provides 25% contrast dose reduction with similar image quality in CTPV. Compared with conventional 120-kVp CT, the use of 60-keV spectral CT images with ASiR algorithm improves CNR values for the intrahepatic portal vein.

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