Combined prospectively electrocardiography- and respiratory-triggered sequential cardiac computed tomography in free-breathing children: success rate and image quality

Background Combined prospectively electrocardiography (ECG)- and respiratory-triggered sequential cardiac computed tomography (CT) has not been evaluated in free-breathing children. Objective To evaluate the success rate and image quality of combined prospectively ECG- and respiratory-triggered sequential cardiac CT in free-breathing children. Materials and methods Image quality of combined prospectively ECG- and respiratory-triggered sequential cardiac CT in 870 children (<= 5 years of age) was evaluated in terms of severe motion (maximal distance >= 2 mm) and band artifacts (maximal attenuation difference >= 100 Hounsfield units). The success rate of the scan mode was calculated. The causes of failed cases were assessed. Patient-related, radiation and image quality parameters were compared between success and failure groups. Results Severe motion artifacts were observed in 10.6% (92/870) of patients due to cardiac phase error in 17 (18.5%), patient motion in 12 (13.0%), and unknown causes in 63 (68.5%). Severe band artifacts were seen in 13.2% (115/870) of patients. Combined prospectively ECG- and respiratory-triggered sequential cardiac CT was successfully performed in 78.5% (683/870) of patients, while it failed in 21.5% (187/870). All the evaluated patient-related, radiation and image quality parameters were significantly different (P <= 0.001) between success and failure groups except effective dose (P > 0.05). Conclusion Additional prospective respiratory triggering can reduce motion artifacts in prospectively ECG-triggered sequential cardiac CT in free-breathing children.