Jia Yulin MD, Presenter: Nothing to Disclose

Xiao Xigang MD, Abstract Co-Author: Nothing to Disclose

Xie Dexuan, Abstract Co-Author: Nothing to Disclose

To evaluate the feasibility of 100kVp acquisition with an iterative reconstruction (IR) technique in retrospective ECG–gated thoracoabdominal aortic CT angiography (CTA).

37 patients who underwent clinically indicated thoracoabdminal aortic CTA with 256–slice CT scanner were randomly distributed into two groups; 18 were scanned with a routine dose (120 kVp, 200–300 mAs) and 19 with a low dose (100 kVp, 200 mAs). All of them provided their written informed consent. BMI of both groups were in the range of 20–25 kg/m2. The low–dose–group (LDG) was reconstructed by standard filtered backprojection (FBP) reconstruction technique, non–tagged technique and level 1 to 6 of iDose4 IR technique. All images were assessed in terms of quantitative and qualitative image quality on Extended Brilliance Workspace (EBW).

Compared with the routine–dose–group (RDG) (SD, 43.8±19.7; CNR, 28.6±11.6), level 6 of iDose4 IR technique for the LDG resulted in low image noise (29.9±11.8, Ρ<0.05) and high CNR (35.7±13.8, Ρ<0.05). The image quality was grade4 in 4 patients, 3 in 12 patients and 2 in 3 patients in the LDG reconstructed by level 6 of iDose4 IR technique, with no significant difference from the RDG. The average CTDIvol of LDG (8.5mGy) was lower than that of RDG (14.5mGy). Besides, in the LDG, level 6 of iDose4 IR technique resulted in low image noise (Ρ<0.00625) and high CNR (Ρ<0.00625), with no significant difference from the non–tagged reconstruction technique, also in the aspect of the image quality.

100 kVp acquisition with level 6 of iDose4 IR technique can improve image quality on the basis of radiation dose reduction in retrospective ECG–gated thoracoabdominal aortic CTA. Non–tagged reconstruction technique may obtain the similar effectiveness with level 6 of iDose4 IR technique except that it loses the ECG–gated information.

The image quality of the whole aorta scanned with low radiation dose can be improved by IR technique significantly and may be equal to or even exceeding that scanned with routine dose.

Yulin, J, Xigang, X, Dexuan, X, Clinical Application of 100 kVp Acquisition and Iterative Reconstruction Technique in Retrospective ECG-gated Thoracoabdominal Aortic CT Angiography.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12024172.html