Reducing contrast medium dose with low photon energy images in renal dual-energy spectral CT angiography and adaptive statistical iterative reconstruction (ASIR)

• DOI: 10.1259/bjr.20200974
• Publication Date: 2021-03-09T00:09:54Z
• Authors: Xirong Zhang; Jing Chen; Nan Yu; Zhanli Ren; Qian Tian; Xin Tian; Yongjun Jia; Taiping He; Changyi Guo
• Keywords: Monochromatic color; Image noise

Objective: To evaluate the value of using low energy (keV) images in renal dual-energy spectral CT angiography (CTA) and adaptive statistical iterative reconstruction (ASIR) to reduce contrast medium dose. Methods: 40 patients with CTA on a Discovery CT750HD were randomly divided into two groups: 20 cases (Group A) 600 mgI kg−1 B) 300 kg−1. The scan protocol for both groups was: mode mA selection noise index 10 HU, pitch 1.375:1, rotating speed 0.6 s/r. Images reconstructed at 0.625 mm thickness 40%ASIR, Group A used conventional 70keV monochromatic images, B from 70 keV 5 interval analysis. values standard deviation (SD) artery erector spine plain arterial phases measured SD representing image noise. enhancement degree (ΔCT = CT(arterial) -CT(plain)), signal-to-noise ratio (SNR=CTrenal-artery/SDrenal-artery) contrast-to-noise (CNR=(CTrenal-artery-CTerector spine)/SDerector-spine) calculated. single factor analysis variance was analyze difference ΔCT, SNR CNR among p < 0.05 being statistically significant. subjective scores assessed blindly by experienced physicians 5-point system score consistency compared κ test. Results: Contrast dose group reduced 50% group, while radiation similar between groups. 4.00 ± 0.65, 4.50 0.60 3.70 0.80 (600 group), (300 group) 45 respectively good reviewers (p > 0.05). had ΔCT (469.77 86.95 HU vs 398.54 73.68 HU) (15.52 3.32 18.78 6.71) as kg−1) but higher (30.19 4.41 16.91 11.12, 0,05) Conclusion: may be maintaining quality lower combined ASIR CTA. Advances knowledge: Combined spectrum, can amount