Three months later, following induction of ICS treatment, the patient’s lung function test results were improved: 109.6% of FVC, 116.3% of FEV1, 88.7% of FEV1/FVC, and 60.7% of the predicted diffuse capacity for carbon monoxide. The repeated CT scan showed improvement of airway thickening, and the previously seen multifocal consolidation was absent (Figs 1C, 1D). Airway lumen diameter (ALD), airway outer diameter (AoD), lumen area (Ai), and outer airway area (Ao) were measured using custom software. As indexes of airway wall dimensions, Ai was used for assessing luminal narrowing, and airway wall thickness (Awt) (Awt = (AoD − ALD)/2), Awt/ALD, airway wall area (WA) (WA = Ao − Ai), and percentage of WA (WA% = WA/Ao × 100) were used to assess airway remodeling.1,2,3 At the right B1, Ai increased from 15.41 mm2 to 20.44 mm2, Awt decreased from 1.57 mm to 1.53 mm, and Awt/ALD decreased from 0.21 to 0.19. WA increased from 29.57 to 31.97 mm2, and WA% decreased from 65.74% to 61.00%. At the right B10, Ai increased from 22.79 to 30.36 mm2, Awt decreased from 1.72 to 1.34 mm, and Awt/ALD decreased from 0.19 to 0.15. WA decreased from 38.05 to 28.20 mm2, and WA% decreased from 62.73% to 51.19%. There was no difference in lung volumes before (4.519 L) or after (4.517 L) treatment according to three-dimensional CT scan volumetric analysis. Therefore, with the exception of WA in B1, the CT scan-estimated airway wall dimensions were improved.