The value of advanced iterative reconstruciton in cardiac computed tomography angiography with low-dose in obese patients

SHU Zhen-yu; DING Zhong-xiang; PAN Yu-ning; XU Jian

Abstract：Objective To investigate the image quality and radiation dose of CT coronary angiography using 3D Adaptive Iterative Dose Reduction and low-dose scan in obese patients. Methods There were sixty consecutive obese patients with BMI higher than thirty of suspected coronary artery disease for prospective electrocardiogram (ECG)-triggering scanner u-sing Toshiba Aquilion one 640-slice CT. These sixty consecutive patients were randomly divided into two groups equally. The tube voltage according to paradigm was 120 kV in group A and 100 kV in group B. All raw data in group A were re-constructed by the software FBP in CT system. All raw data in group B were reconstructed by the software FBP and 3D AIDR in CT system to create two new group named as B1 and B2. The values such as SI, SD, SNR, CNR, and image quality scores were compared between group B1 and group B2. The significance of group B2 and group A1 was compamd in SI, SD, SNR, CNR, ED and image quality scores as well. Results Effective dose in group B was significantly lower than that in group A〔E= (5. 37 ± 0. 49) mSv in group B vs E= (2. 18 ± 0. 84) mSv in group A〕. The value of E in group B was decreased by 59% compared to group A. There was significant difference in mean image quality scores between B1 group and B2 group (1. 41 ± 1. 09 in group B1 vs 2. 28 ± 0. 98 in group B2, t =-12. 113, P <0. 05). There was no significant difference in mean image quality scores between A group and B2 group (2. 22 ± 0. 97 in group A1 vs 2. 28 ± 0. 98 in group B2, t=0. 963, P>0. 05). The values of SI, SD, SNR, and CNR in group A were (439. 5 ± 68. 2) HU, 32. 1 ± 6. 8, 12.6 ± 5.7, 11. 2 ± 3. 4. The values of SI, SD, SNR, and CNR in group B1 were (523. 2 ± 85. 2) HU, 64. 8 ± 6. 9, 8. 3 ± 3. 2, 7.5 ± 6. 9. The values of SI, SD, SNR, and CNR in group B2 were (505. 1 ± 48. 4) HU, 38. 6 ± 7. 4, 13. 8 ± 5. 1, 11. 6 ± 2. 8. There was difierence in the SD, SNR, and CNR between group B1 and group B2 ( t =2. 378, 0. 812, 1. 461, P <0.05). There was difierence in the SI and SD between group A and group B2 ( t=-2. 829, -0. 241, P<0. 05). There was no difierence in the SNR and CNR between group A and group B2 ( t =1. 128, 0. 672, P>0. 05). Conclusion 3D AIDR improves the image quality with in the same doses. Its combination with 100 kV scan can tet coronary artery image quality met the needs of diagnosis and greatly reduce the radiation dose in CTCA.