Optimization of image quality and radiation dose in low-dose pediatric chest CT Using 80 kVp acquisition and variable ASiR-V reconstruction

Radiation dose reduction in pediatric chest computed tomography (CT) is crucial because of increased radiosensitivity and potential long-term cancer risk. Low tube voltage combined with iterative reconstruction can reduce radiation exposure; however, the optimal reconstruction strength that balances image quality and diagnostic acceptability remains unclear. In addition, evidence remains limited regarding the optimal ASiR-V blending level in pediatric low-dose chest CT, particularly when subjective image quality, objective metrics, and radiation dose are evaluated together. This retrospective study included 200 children (0–6 years) undergoing chest CT. One hundred patients were scanned using an 80 kVp protocol reconstructed with 6 adaptive statistical iterative reconstruction-V (ASiR-V) blending levels (0–100%), and 100 patients underwent conventional 100 kVp CT. Subjective image quality was independently assessed by 2 radiologists using a five-point scale under lung and mediastinal window settings. Objective image quality was evaluated using image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Radiation dose parameters, including CTDIvol, dose–length product, and effective dose, were recorded and compared. Radiation dose metrics were significantly lower with the 80 kVp protocol than with the 100 kVp protocol (all P  < .001), resulting in an approximately 48% reduction in effective dose. Image noise progressively decreased with increasing ASiR-V blending levels, accompanied by corresponding increases in SNR and CNR, with optimal objective values at 100% ASiR-V. Subjective image quality peaked at intermediate blending levels, with ASiR-V 80% achieving the highest diagnostic acceptability and scores comparable to those of conventional 100 kVp CT. Low-dose pediatric chest CT using 80 kVp acquisition achieves substantial radiation dose reduction while maintaining diagnostic image quality when optimized iterative reconstruction is applied. Among the 6 ASiR-V blending levels evaluated, ASiR-V 80% provided the most favorable balance between subjective diagnostic acceptability, noise suppression, and preservation of image texture, whereas ASiR-V 100% yielded the best objective noise-related metrics.