Evaluation of image quality and radiation dose with prospective ECG-gated 80 multi-slice CT scan in 182 consecutive children examinations with congenital heart disease

Abstract

Computed tomography angiography (CTA) is a reliable imaging tool to evaluate children congenital heart disease (CHD) but requires radiation exposure. This study aims to investigate image quality and radiation dose with a prospective electrocardiogram (ECG)-gated 80 multi-slice CTA, in 182 consecutive children examinations with CHD. In total, 182 consecutive examinations performed with a prospective ECG-gated 80 multi-slice CTA from March 2016 to December 2017 in Nantes university hospital were retrospectively analyzed. Radiation dose was assessed by dose length product (DLP) and effective dose (E). Objective quality image was assessed by contrast to noise ratio (CNR). Subjective quality image was assessed by two radiologists with a 10-point scale evaluating visualization of coronary arteries. Correlation between quality image, radiation dose, age, weight, heart rate was analyzed. DLP and E were 29.3 ± 15.5 mGy.cm and 0.6 ± 0.2 mSv, respectively. Agreement between radiologists in assessment of subjective image quality was 0.79. Subjective image quality score was significantly better ( P < 0.01) with higher age, weight, DLP and lower heart rate in univariate analysis. CNR was significantly lower with increasing weight and DLP ( P < 0.05) but there was no correlation between CNR and age and heart rate. Prospective ECG-gated 80 multi-slice CTA is performing for the evaluation of children CHD with good image quality and low radiation dose. Visualization of small structures is better when age and weight increase, heart rate decreases and when radiation dose is more important. CNR evolves in the opposite side to subjective image quality score. It seems less appropriate to assess image quality from clinical viewpoint of the radiologist.