Dual-energy compared to single-energy CT in pediatric imaging: a phantom study for DECT clinical guidance

Dual-energy CT technology is available on scanners from several vendors and offers significant advantages over classic single-energy CT technology in multiple clinical applications. Many studies have detailed dual-energy CT applications in adults and several have evaluated the relative radiation dose performance of dual-energy CT in adult imaging. However, little has been published on dual-energy CT imaging in the pediatric population, and the relative dose performance of dual-energy CT imaging in the pediatric population is not well described.

When evaluating dual-energy CT technology for implementation into a routine clinical pediatric imaging practice, the radiation dose implications must be considered, and when comparing relative CT dose performance, image quality must also be evaluated. Therefore the purpose of this study is to develop dual-energy CT scan protocols based on our optimized single-energy scan protocols and compare the dose.

We scanned the head, chest and abdomen regions of pediatric-size anthropomorphic phantoms with contrast inserts, using our optimized single-energy clinical imaging protocols on a Siemens Flash® CT scanner. We then scanned the phantoms in dual-energy mode using matching image-quality reference settings. The effective CT dose index volume (CTDI_vol) of the scans was used as a surrogate for relative dose in comparing the single- and dual-energy scans. Additionally, we evaluated image quality using visual assessment and contrast-to-noise ratio.

Dual-energy CT scans of the head and abdomen were dose-neutral for all three phantoms. Dual-energy CT scans of the chest showed a relative dose increase over the single-energy scan for 1- and 5-year-old child-based age-equivalent phantoms, ranging 11-20%. Quantitative analysis of image quality showed no statistically significant difference in image quality between the single-energy and dual-energy scans. There was no clinically significant difference in image quality by visual assessment.

Dual-energy CT is dose-neutral in imaging the head and abdomen in children. It is not dose-neutral in chest imaging of very small children. With a better understanding of the dose consequences of converting single-energy protocols to dual-energy protocols we can begin to implement clinical dual-energy CT and utilize its unique capabilities in pediatric imaging.