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Updated: Sep 20, 2025
Retrospective Cardiac Gating with A Prototype Small-Animal X-ray Computed Tomograph
Published on: February 21, 2025
Radiation dose in 1-60-month children undergoing 64-detector cardiac CT angiography: ECG-gated versus non-gated scans
T Masuda1, T Nakaura2, Y Funama3
1Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama, 701-0193, Japan.
Insights
Retrospective electrocardiogram (ECG)-gated cardiac computed tomography angiography (CTA) in pediatric patients resulted in approximately 10 times higher radiation dose compared to non-gated scans. Image quality and noise levels remained comparable between the two methods.
Area of Science:
- Radiology
- Pediatric Imaging
- Radiation Dose Optimization
Background:
- Cardiac computed tomography angiography (CTA) is essential for pediatric cardiovascular assessment.
- Understanding radiation exposure differences between ECG-gated and non-gated helical scans is critical for patient safety.
Purpose of the Study:
- To investigate and compare the radiation exposure dose of ECG-gated versus non-gated helical scans in pediatric cardiac CTA.
- To evaluate the impact of scan type on image quality parameters.
Main Methods:
- A retrospective analysis of 63 pediatric patients (1-60 months) undergoing cardiac CTA.
- Patients were divided into non-gated helical (33) and retrospective ECG-gated (30) scan groups using a 64-detector-row CT.
- Comparison of CT dose-volume index (CTDIvol), dose-length product (DLP), effective dose (ED), CT values, and image noise.
Main Results:
- ECG-gated scans showed approximately 10 times higher radiation doses (CTDIvol, DLP, ED) than non-gated scans (P < 0.01).
- No statistically significant differences were observed in CT values of the aorta and pulmonary artery between the groups (P < 0.05).
- Image noise levels were comparable between retrospective ECG-gated and non-gated helical scans (P < 0.05).
Conclusions:
- Retrospective ECG-gated cardiac CTA significantly increases radiation exposure in pediatric patients compared to non-gated helical scans.
- The choice of scanning technique is crucial for minimizing radiation dose while maintaining diagnostic image quality.
- Adherence to the ALARA principle (As Low As Reasonably Achievable) is paramount in pediatric cardiac CTA.
Introduction:
Investigating the extent to which the exposure dose differs in cardiac computed tomography angiography (CTA) between electrocardiogram (ECG)-gated and non-gated helical scan is crucial. We aimed to investigate the difference in radiation dose with cardiac CTA between ECG-gated and non-gated helical scans in pediatric patients.
Methods:
Between January 2015 and November 2021, for the study cohort for the retrospective cardiac CTA study, we enrolled 63 pediatric patients aged 1-60 months and divided them into non-gated helical (33 patients) and retrospective ECG-gated (30 patients) scans with a 64-detector-row CT. We compared the CT dose-volume index (CTDIvol), dose-length product (DLP), effective dose (ED), CT values of the aorta and pulmonary artery, and image noise between the two groups. We calculated 95 % confidence intervals (CIs).
Results:
Compared with the non-gated helical and ECG gated scans, CTDIvol were 0.5 ± 0.1 and 5.7 ± 1.4 mGy (P < 0.01: 95 % CI, from -5.7 to -4.7), DLPs were 8.6 ± 2.8 and 72.6 ± 24.6 mGy・cm (P < 0.01: 95 % CI, from -72.6 to -55.3), and EDs were 0.2 ± 0.1 and 1.9 ± 0.6 mSv (P < 0.01: 95 % CI, from -1.9 to -1.4), respectively. Radiation dose for retrospective ECG-gated scans was approximately 10 times higher than that for non-gated helical scans. There were no significant differences in the CT values and image noise between the retrospective ECG-gated and non-gated helical scans (all p < 0.05).
Conclusion:
The radiation dose for retrospective ECG-gated scans with cardiac CTA was approximately 10 times higher than that for non-gated helical scans without any reduction in image noise or contrast enhancement.
Implications For Practice:
The radiation dose should be as low as reasonably achievable, and the selection of the scan method is pivotal in clinical practice.
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