Quantitative CT and pulmonary function in children with post-infectious bronchiolitis obliterans

OBJECTIVE: To investigate the feasibility of CT-based quantitative airway and air-trapping measurements and to assess their correlation with pulmonary function in children with post-infectious bronchiolitis obliterans (PIBO). MATERIALS AND METHODS: This retrospective study approved by the institutional review board included chest CT scans and pulmonary function tests (PFT) completed between January 2005 and December 2016 in children diagnosed with PIBO. The quantitative analysis of segmental and subsegmental bronchi was performed on each chest CT scan, measuring the areas or diameters of lumens, walls, or the entire airway. The air-trapping volume (ATV), the volume of lung area exhibiting lower attenuation than the mean attenuation of normal and air-trapping areas, was also measured in each lobe. Comparison analyses between CT parameters and PFT results were performed with Pearson or Spearman correlation. RESULTS: In total, 23 patients were enrolled (mean age 7.0 ± 3.3 years; range, 4–15 years). We successfully measured 89.6% of all segmental bronchi. In the airway analysis, wall area showed a negative correlation with forced expiratory volume in one second (FEV(1)) in the majority of the pulmonary lobes. Air-trapping analyses demonstrated that ATV was negatively correlated with FEV(1) and positively correlated with reactance at 5 Hz. CONCLUSION: Quantitative airway and air-trapping measurements from chest CT are feasible and correlate with pulmonary function in pediatric PIBO patients.