Three-dimensional airway lumen volumetry: comparison with bronchial wall area and parenchymal densitometry in assessment of airway obstruction in pulmonary emphysema.

OBJECTIVES

The purpose of this study was to compare three-dimensional airway lumen volumetry with bronchial wall area and parenchymal densitometry in the assessment of airway obstruction in pulmonary emphysema.

METHODS

56 patients, who were smokers, underwent CT examination and pulmonary function tests (PFTs). For quantitative assessments, the following parameters were computationally calculated: (1) percentage of voxels -950, -960 and -970 HU in the lung (%LAA(-950), %LAA(-960) and %LAA(-970), respectively); (2) percentage of partial bronchi luminal volumes per total luminal volumes (LV(main), main and distal bronchial volume/total luminal volume; LV(lobe), lobar and distal bronchial volume/total luminal volume); and (3) mean wall area percentages of segmental bronchi of the right apical and left apicoposterior segment (WA%(seg)) and of subsegmental bronchi (WA%(sub)) in the upper lobes. These parameters were correlated with PFTs and statistically compared between a chronic obstructive pulmonary disease (COPD) group [forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)<70] and a non-COPD group.

RESULTS

FEV1, maximum mid-expiratory flow rate and forced expiratory flow at 25% vital capacity had significant correlation with LV(main) (r>0.53, p<0.0001), LV(lobe) (r>0.52, p<0.0001), WA%(seg) (|r|>0.29, p<0.05) and WA%(sub) (|r|>0.31, p<0.05). FEV1/FVC had significant correlation with all parameters (0.27<|r|<0.52, p<0.05). LV(main) and LV(lobe) and WA%(seg) and WA%(sub) were significantly different between the two groups (LV(main) and LV(lobe); p<0.0001, WA%(seg) and WA%(sub); p<0.05).

CONCLUSIONS

Bronchial luminal volumetric assessment better reflected the airflow limitation parameters.

ADVANCES IN KNOWLEDGE: Bronchial luminal volumetric assessment can potentially be used to gauge airflow limitation in pulmonary emphysema.