| Zhao Yongxia,Chang Jin,Zuo Ziwei,et al.Optimization of low-dose protocol in thoracic aorta CTA: weighting of adaptive statistical iterative reconstruction (ASIR) algorithm and scanning parameters[J].Chinese Journal of Radiological Medicine and Protection,2014,34(11):867-869 |
| Optimization of low-dose protocol in thoracic aorta CTA: weighting of adaptive statistical iterative reconstruction (ASIR) algorithm and scanning parameters |
| Received:November 13, 2013 |
| DOI：10.3760/cma.j.issn.0254-5098.2014.11.019 |
| KeyWords:Adaptive statistical iterative reconstruction Radiation dose Image quality Thoracic aorta CTA |
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| Abstract:: |
| Objective To investigate the best weighting of adaptive statistical iterative reconstruction (ASIR) algorithm and optimized low-dose scanning parameters in thoracic aorta CT angiography(CTA). Methods Totally 120 patients with the body mass index (BMI) of 19-24 were randomly divided into 6 groups. All patients underwent thoracic aorta CTA with a GE Discovery CT 750 HD scanner (ranging from 290-330 mm). The default parameters (100 kV,240 mAs) were applied in Group 1. Reconstructions were performed with different weightings of ASIR(10%-100% with 10%), and the signal to noise ratio (S/N) and contrast to noise ratio(C/N) of images were calculated. The images of series were evaluated by 2 independent radiologists with 5-point-scale and lastly the best weighting were revealed. Then the mAs in Group 2-6 were defined as 210,180,150,120 and 90 with the kilovoltage 100. The CTDIvol and DLP in every scan series were recorded and the effective dose (E) was calculated. The S/N and C/N were calculated and the image quality was assessed by two radiologists. Results The best weighing of ASIR was 60% at the 100 kV,240 mAs. Under 60% of ASIR and 100 kV, the scores of image quality from 240 mAs to 90 mAs were(4.78±0.30)-(3.15±0.23). The CTDIvol and DLP were 12.64-4.41 mGy and 331.81-128.27 mGy, and the E was 4.98-1.92 mSv. The image qualities among Group 1-5 were nor significantly different (F＝5.365,P>0.05), but the CTDIvol and DLP of Group 5 were reduced by 37.0% and 36.9%,respectively compared with Group 1. Conclusions In thoracic aorta CT Angiography, the best weighting of ASIR is 60%, and 120 mAs is the best mAs with 100 kV in patients with BMI 19-24. |
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