Ultralow dose computed tomography as an alternative to conventional chest radiography for the evaluation of disease severity in paediatric cystic fibrosis

Chest computed tomography (CT) surpasses chest radiography (CR) in accurately assessing disease severity and detecting early structural pulmonary changes in patients with cystic fibrosis (CF). Chest CT provides detailed visualisation and quantification of CF-specific lung pathologies and can reveal these changes before they manifest clinically or become detectable on CR. The past decade has witnessed the advent and refinement of radiation-reducing techniques in CT which have enabled substantial dose reductions. Our study prospectively evaluates the efficacy of ultra-low dose CT (ULDCT) chest in identifying pulmonary changes within a paediatric patient cohort. Paediatric patients with CF, who presented for routine clinical outpatient follow-up between 01/07/2022, and 01/07/2023 underwent ULDCT and CR (if not recently performed) and image analysis was performed. Radiation dose, subjective and objective image quality and disease severity were recorded. 45 patients (mean age 10.5 years) underwent clinically indicated ULDCT chest ± CR. The mean effective dose was of ULDCT was 0.07 ± 0.01 mSv, a dose that approximates that of a frontal and lateral chest radiograph. The average ULDCT Brody II severity score across the entire cohort was 5.62, with excellent inter-rater reliability and intra-class correlation coefficient (ICC) of 0.98 (95% CI = 0.96, 0.99). The average Chrispin-Norman score on chest radiograph was 0.93 with moderate inter-rater reliability and ICC of 0.64 (95% CI = 0.19, 0.83). In light of its superior diagnostic capabilities, minimal radiation dose penalty, we advocate for ULDCT to be the preferred modality for surveillance imaging in paediatric patients with CF.