Structural lung assessment in children with primary ciliary dyskinesia: evaluation with the SPEC scoring system

Primary ciliary dyskinesia (PCD) is a rare genetic disorder that may result in progressive lung damage. The Specific PCD Evaluation by CT (SPEC) scoring system has been specifically used in PCD patients since 2024. This study aimed to evaluate the SPEC score in children with PCD. This retrospective, cross-sectional, single-center study included 47 children with confirmed or highly likely PCD who underwent thin-section thoracic computed tomography (CT). Pediatric radiologists evaluated CT scans using SPEC, Bhalla, and modified Brody scoring systems. We analyzed pulmonary function tests performed within 3 months of CT. We compared its performance with established scoring systems. The median age at CT was 8 years (Q1-Q3: 5.5-13.0). SPEC scores ranged from 0 to 51 (median 29). All three CT scoring systems showed strong intercorrelations; the SPEC-modified Brody correlation was ρ = 0.894 (p < 0.001), and the SPEC-Bhalla correlation was ρ =  - 0.838 (p < 0.001). SPEC scores showed strong negative correlations with FEV₁ z-score (ρ =  - 0.748, p < 0.001) and FVC z-score (ρ =  - 0.722, p < 0.001) and positively correlated with age (ρ = 0.425, p = 0.003). SPEC scoring showed bronchiectasis predominantly in the lower and middle lobes, with the left lower lobe most frequently affected (68.1%). Conlsuions: The SPEC scoring system is valid for assessing structural lung disease in children with PCD. Strong correlations with pulmonary function and established CT scoring systems support its clinical utility. SPEC may help guide treatment decisions and serve as an outcome measure in pediatric PCD trials. What is Known: • Bhalla and modified Brody CT scoring systems were developed for cystic fibrosis and may not fully capture PCD-specific findings. • SPEC, introduced in 2024 as the first PCD-specific CT scoring system, has limited pediatric data. • Structural lung damage in PCD is progressive and may precede spirometric decline. What is New: • This study provides an independent pediatric application cohort for the SPEC scoring system, outside the development study. • SPEC scores correlated strongly with pulmonary function parameters. • SPEC can guide clinical decisions and serve as an outcome measure in the pediatric PCD population.