Changes in Airway Dimensions on Computed Tomography Scans of Children with Cystic Fibrosis

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Abstract
Rationale: In cystic fibrosis (CF), chronic bacterial infection and inflammation lead to progressive airway wall thickening and lumen dilatation. Objectives: To quantify airway wall thickening and lumen dilatation in children with CF over a 2-year interval. Methods: Children with CF (n = 23) who had two computed tomography (CT) scans (CTcf1 and CTcf2) combined with pulmonary function tests (PFTs), with a 2-year interval between measurements, were compared with control subjects (n = 21) who had one CT (CTcontrols). On cross-sectional cut airway–artery pairs, airway wall area (WA), airway lumen area (LA) and perimeter, and arterial area (AA) were quantified. LA/AA (= marker of bronchiectasis), airway wall thickness (AWT), and WA/AA (= markers of wall thickness) were calculated. CT scans were scored using four different scoring systems. PFTs were expressed as percent predicted. Results: Airway WA-to-AA ratio was 1.45 (p < 0.001) and airway LA-to-AA ratio was 1.92 times higher (p < 0.001) in children with CF compared with age-matched control subjects. LA/AA and WA/AA remained unchanged from CTcf1 to CTcf2 and did not increase with age. AWT as a function of airway size increased from CTcf1 to CTcf2 by 2% (0.03 mm; p = 0.02). The change in AWT was inversely related to the change in forced expiratory flow between 25 and 75% of expiratory VC (p = 0.002). Conclusions: In CF, quantitative measurements of airways on CT scans show an increased ratio between airway LA and AA and progressive airway wall thickening. Scoring systems show progression of bronchiectasis but unchanged AWT. PFTs remained stable.