Abstract
PURPOSE: To develop a novel method for calculating small airway resistance using computational fluid dynamics (CFD) based on CT data and evaluate its value to identify COPD. PATIENTS AND METHODS: 24 subjects who underwent chest CT scans and pulmonary function tests between August 2020 and December 2020 were enrolled retrospectively. Subjects were divided into three groups: normal (10), high-risk (6), and COPD (8). The airway from the trachea down to the sixth generation of bronchioles was reconstructed by a 3D slicer. The small airway resistance (R(SA)) and R(SA) as a percentage of total airway resistance (R(SA)%) were calculated by CFD combined with airway resistance and FEV(1) measured by pulmonary function test. A correlation analysis was conducted between R(SA) and pulmonary function parameters, including FEV(1)/FVC, FEV(1)% predicted, MEF50% predicted, MEF75% predicted and MMEF75/25% predicted. RESULTS: The R(SA) and R(SA)% were significantly different among the three groups (p<0.05) and related to FEV(1)/FVC (r = -0.70, p < 0.001; r = -0.67, p < 0.001), FEV(1)% predicted (r = -0.60, p = 0.002; r = -0.57, p = 0.004), MEF50% predicted (r = -0.64, p = 0.001; r = -0.64, p = 0.001), MEF75% predicted (r = -0.71, p < 0.001; r = -0.60, p = 0.002) and MMEF 75/25% predicted (r = -0.64, p = 0.001; r = -0.64, p = 0.001). CONCLUSION: Airway CFD is a valuable method for estimating the small airway resistance, where the derived R(SA) will aid in the early diagnosis of COPD.