Xiao-ying Wang, Presenter: Research Grant, General Electric Company

Mengxi Jiang, Abstract Co-Author: Research Grant, General Electric Company

Mingyu Zou PhD, Abstract Co-Author: Research Grant, General Electric Company

Chuang Yi, Abstract Co-Author: Research Grant, General Electric Company

Gang Hu, Abstract Co-Author: Research Grant, General Electric Company

Rui Wang, Abstract Co-Author: Research Grant, General Electric Company

He Wang MD, Abstract Co-Author: Research Grant, General Electric Company

Baocui Zhang, Abstract Co-Author: Research Grant, General Electric Company

Fusheng Gao MD, Abstract Co-Author: Research Grant, General Electric Company

Jian Luo, Abstract Co-Author: Research Grant, General Electric Company

Jian Jiang, Abstract Co-Author: Research Grant, General Electric Company

Chenglin Zhao, Abstract Co-Author: Research Grant, General Electric Company

To investigate the feasibility of low kVp and low iodine scan protocol in coronary computed tomography angiography (CCTA) to reduce radiation dose without undermining image quality.

200 consecutive patients with body mass index (BMI) 20-25 kg/m2 undergoing prospectively electrocardiogram-triggered CCTA were randomized into four groups at 4 sites. Group A: using 80kVp and iodixanol 270 mgI/mL with 60% adaptive statistical iterative reconstruction (ASiR); group B: using 100kVp and iodixanol 270 mgI/mL with 30-40% ASiR; group C: using 100kVp and iodixanol 320 mgI/mL with 30-40% ASiR; group D: using 120kVp and iopromide 370 mgI/mL with filtered back projection. 60 ml contrast was given at 5 ml/s intravenously. CT values of 18 coronary artery segments were measured. Image quality was assessed by 2 experienced radiologists blinded to examination, using a 4-point scale (1-4: nondiagnostic-excellent). An assigned score of 1 in any segments was graded the image as nondiagnostic. Noise, contrast-to-noise (CNR), signal-to-noise ratio (SNR) and size-specific dose estimate (SSDE) were also calculated.

163 subjects completed study. CT values of all segments in all groups met clinical diagnostic requirement. There was no significant difference in image quality among the four groups (3.4 ± 0.7, 3.5 ± 0.5, 3.6 ± 0.4, 3.6 ± 0.3 respectively).The average CT value in group A (n=37) was higher than that in group B (n=45), C (n=40) and D (n=41) (all p < 0.05). Noise in group A (40.6 ± 8.5 HU) was significantly higher than that in group B (28.8 ± 6.7 HU), C (28.5 ± 4.6 HU) and D (29.1 ± 4.8 HU) (all p < 0.001), while CNR and SNR in group A was lower than that in group C and D (both p < 0.001). Compared with group D, the mean SSDE was reduced by 56.2%, 34.7%, and 34.3% in group A, B, C respectively.

All low kVp scans achieved a good image quality with significantly reduced radiation dose. 80 kVp with iodixanol 270 mgI/mL in prospectively electrocardiogram-triggered CCTA for patients with a normal BMI is practicable.

With a prospective comparison, the study result has solidified the use of low tube voltage and low iodine enhancement in CCTA. It is time to promote 80 kVp CCTA protocol in clinical to benefit patients from 50% reduction of radiation dose.

Wang, X, Jiang, M, Zou, M, Yi, C, Hu, G, Wang, R, Wang, H, Zhang, B, Gao, F, Luo, J, Jiang, J, Zhao, C, Realizing Radiation and Iodine Dose Reduction in Coronary CT Angiography by Using Adaptive Statistical Iterative Reconstruction.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14007009.html