The Association Between Bronchial Wall CT Attenuation and Spirometry in Patients with Bronchial Asthma

Rationale and Objective: The purpose of this study was to evaluate the correlation between generation-based bronchial wall attenuation on thin-section computed tomography (CT) scans and airflow limitation in patients with bronchial asthma. Materials and Methods: This study included 28 bronchial asthma patients (13 men, 15 women; age range, 23-89 years) who underwent both chest CT and spirometry. On CT, the mean values of peak wall attenuation, wall area percentage, and lumina! area were measured in the segmental, subsegmental, and sub-subsegmental bronchi of the right B1 and B10 bronchi. Correlations of the CT measurements with forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC), percent predicted forced expiratory flow at 25%-75% of the FVC (%pred forced expiratory flow25-75), and percent predicted peak flow rate were evaluated with Spearman's rank correlation test. Results: The peak wall attenuation of each generation of segmental bronchi significantly correlated with the forced expiratory volume in 1 second/FVC (B1 segmental, rho=0.683, p < 0.0001; B1 subsegmental, rho=-0.875, p < 0.0001; B1 sub-subsegmental, rho=-0.926, p < 0.0001; B10 segmental, rho=0.811, p < 0.0001; B10 subsegmental, rho=-0.903, p < 0.0001; B10 sub-subsegmental rho=-0.950, p < 0.0001). Similar correlations were found between the peak wall attenuation and %pred forced expiratory flow 25-75 or percent predicted peak flow rate. Overall, the correlation coefficients were relatively high in the more peripheral bronchial generations. In all measurements, the coefficients of the peak wall attenuations were higher than those of the wall area percentage and luminal area. Conclusion: Peak attenuation of the bronchial wall, particularly in the peripheral bronchi, measured on CT is a good biomarker for the severity of bronchial asthma.