Quantitative bronchial luminal volumetric assessment of pulmonary function loss by thin-section MDCT in pulmonary emphysema patients

Objectives: To determine the capability of quantitative bronchial luminal volume to assess pulmonary function loss and disease severity in pulmonary emphysema patients. Methods: Thirty-seven smokers (mean age, 68.1 years) underwent CT examinations and pulmonary function tests. For the quantitative assessment, luminal voxels of trachea and bronchi were computationally counted and the ratio of the following luminal voxels to all luminal voxels was obtained: (1) the lobe bronchi and the peripheral bronchi (Ratio _lobe), and (2) the main bronchi and the peripheral bronchi (Ratio _main). To determine the capability of these assessments to predict pulmonary function loss, these ratios were correlated with pulmonary function tests. To determine the capability for predicting disease severity, these ratios were compared between clinical groups. Results: These ratios were no significant correlated with vital capacity and forced vital capacity (FVC) (p > 0.05), however significantly correlated with forced expiratory volume in 1 s (FEV1) (Ratio _lobe: r = 0.61, p < 0.0001, Ratio _main: r = 0.58, p < 0.0005) and FEV1/FVC (Ratio _lobe: r = 0.36, p < 0.05, Ratio _main: r = 0.33, p < 0.05). The Ratio _lobe of smokers without COPD was significantly different from those of moderate COPD and severe or very severe COPD (p < 0.05), while that of mild COPD was significantly different from that of severe or very severe COPD (p < 0.01). The Ratio _main of severe or very severe COPD patients was significantly different from those of other groups (p < 0.05). Conclusions: Quantitative bronchial luminal volumes were reflected the airflow limitation parameters and was corresponded to clinical groups in emphysema patients.