Strategies for dose-optimized imaging in pediatric cardiac dual source CT

As a result of rapid advances in CT technology, including dual source CT, cardiac CT exams at high heart rates are feasible, making pediatric cardiac CT in congenital heart disease possible. Dose concerns and patient size variability make general recommendations difficult. The aim of this study was to investigate which scanner settings are suitable for multiple weight groups to provide dose-optimized scanning.

All 12 patients underwent a contrast-enhanced gated dual source CT exam. A maximum of 2 ml/kg body weight or 60 ml contrast was applied. Scanner settings at 80 and 120 kV, as well as weight-adapted mAs settings were used in an iterative fashion. Datasets were assessed for image quality and dose-optimized scan parameters were established via class comparison. In a final step a table was created as a recommendation for cardiac CT in children corresponding to their body weight. Strategies for optimized contrast application with hand vs. manual injection were explored.

In all children diagnostic image quality was obtained. In children < 60 kg, 80 kV can be used, in all others 100 kV is sufficient. The eff. mAs varied from 362 mAs to 30 mAs depending on body weight. Retrospectively a significant dose reduction would have been possible in 6 / 12 patients. Cardiac CT can be performed between 0.6 and 3.2 mSv in a pediatric population.

The present study shows that dual source cardiac CT is a potential diagnostic alternative in children with congenital heart disease without excessive radiation exposure or contrast media application.