Feasibility of reducing the contrast dose in infants and children with complex congenital heart disease using virtual monoenergetic images on dual-layer spectral detector computed tomography

BACKGROUND: Virtual monoenergetic imaging (VMI) with dual-layer spectral detector computed tomography (CT) enables keV optimization, offering the potential for contrast dose reduction, particularly beneficial in pediatric imaging. However, its clinical utility in infants and children with complex congenital heart disease (CHD) remains underexplored. OBJECTIVE: To investigate the feasibility of reducing the contrast dose and the optimal keV of virtual monoenergetic images (VMIs) on dual-layer spectral detector CT in infants and children with complex CHD. MATERIALS AND METHODS: Prospectively enrolled 80 infants and children with complex CHD and underwent preoperative dual-layer spectral detector CT. Patients were randomly divided into two groups: group A (n=36, standard dose, 1.5-2 ml/kg) and group B (n=44, low dose, 1 ml/kg). Conventional image and VMIs in range of 40-85 keV were reconstructed in group B while only conventional image was reconstructed in group A. Image quality was evaluated using qualitative scores and objective metrics including CT-value, standard deviation (SD), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) for the pulmonary artery and ascending aorta. RESULTS: Group B received 24% less contrast than group A [8.0 (5.0; 11.0) ml vs. 10.5 (8.0; 21.0) ml, P<0.05]. VMI 40 keV in group B yielded the highest CT-value, SNR, CNR of pulmonary artery, and ascending aorta among different VMIs, and significantly outperformed conventional image in group A (P<0.05). Subjective evaluation score on VMI 40-50 keV of group B was significantly higher than conventional image of group A (P<0.05). Diagnostic accuracy for CHD at 40-50 keV in group B was 97.7%, significantly higher than group A (93.4%, P<0.05), while no significant difference in sensitivity and specificity. CONCLUSION: VMI 40 keV in dual-layer spectral detector CT can significantly improve image quality, allowing contrast dose reduction in infants and children with complex CHD without compromising diagnostic performance.