Diagnosis of bronchiectasis and airway wall thickening in children with cystic fibrosis: Objective airway-artery quantification

Objectives To quantify airway and artery (AA)-dimensions in cystic fibrosis (CF) and control patients for objective CT diagnosis of bronchiectasis and airway wall thickness (AWT). Methods Spirometer-guided inspiratory and expiratory CTs of 11 CF and 12 control patients were collected retrospectively. Airway pathways were annotated semi-automatically to reconstruct three-dimensional bronchial trees. All visible AA-pairs were measured perpendicular to the airway axis. Inner, outer and AWT (outer-inner) diameter were divided by the adjacent artery diameter to compute A(in)A-, A(out)A- and A(WT)A-ratios. AA-ratios were predicted using mixed-effects models including disease status, lung volume, gender, height and age as covariates. Results Demographics did not differ significantly between cohorts. Mean AA-pairs CF: 299 inspiratory; 82 expiratory. Controls: 131 inspiratory; 58 expiratory. All ratios were significantly larger in inspiratory compared to expiratory CTs for both groups (p < 0.001). A(out)A- and A(WT)A-ratios were larger in CF than in controls, independent of lung volume (p < 0.01). Difference of A(out)A- and A(WT)A-ratios between patients with CF and controls increased significantly for every following airway generation (p < 0.001). Conclusion Diagnosis of bronchiectasis is highly dependent on lung volume and more reliably diagnosed using outer airway diameter. Difference in bronchiectasis and AWT severity between the two cohorts increased with each airway generation.