Clinical application of 100Â kVp acquisition with an iterative reconstruction technique in retrospective electrocardiogram-gated thoracoabdominal aortic CT angiography

- 256-slice spiral CT facilitates the retrospective ECG-gated CTA of the whole aorta.
- Retrospective ECG-gating displays dynamic information about aorta and branches.
- 100 kVp can be used for aortic CTA to reduce radiation dose.
- iDose algorithm can improve the image quality with a low radiation dose.
- Non-tagged reconstruction cannot be used for a one-stop examination of the aorta.

AimTo evaluate the feasibility of a 100 kVp tube voltage combined with an iterative reconstruction algorithm in retrospective electrocardiogram (ECG)-gated thoracoabdominal aortic CT angiography (CTA).Materials and methodsNinety-eight patients who underwent clinically indicated thoracoabdominal aortic CTA were randomly assigned to two groups: group A (n = 50) were scanned to 120 kVp and group B (n = 48) to 100 kVp. The body mass index of all included patients was <25 kg/m2. Group A scans were reconstructed with a standard filtered back projection (FBP) algorithm, and group B scans with FBP, iDose, and non-tagged algorithms. Data comparison between groups was performed using t-test and analysis of variance.ResultsCompared with group A, the iDose algorithm in group B yielded a higher contrast-to-noise ratio (CNR; 48.1 ± 10.1, p < 0.05), a higher signal-to-noise ratio (SNR; 13.8 ± 5.4, p < 0.05), and a lower standard deviation (SD; 30.3 ± 6.9, p < 0.05). The subjective score of iDose reconstructions from group B was significantly lower than that of FBP reconstruction from group A (p < 0.05). In group B, the non-tagged algorithm resulted in a higher CNR and a higher SNR, but a higher SD and a higher subjective score than did the iDose algorithm. The average effective dose for group B was 35.8% lower than that for group A.ConclusionA combination of a 100 kVp tube voltage and the iDose algorithm can help to improve image quality and reduce radiation dose in retrospective ECG-gated thoracoabdominal aortic CTA.