Relationships between High-Resolution Computed Tomography, Lung Function and Bacteriology in Stable Bronchiectasis

To determine the relationship between high-resolution computed tomography (HRCT) findings, lung function, and bacteriology in bronchiectasis, we conducted a retrospective study of 49 Korean patients with stable bronchiectasis. To quantify the extent and severity of bronchiectasis, we used a CT scoring system consisting of bronchial dilatation, bronchial wall thickening, the number of bronchiectatic segments, the number of bulla, and the number of emphysema segments. The presence of air-fluid levels and lung consolidation were also evaluated. The results of CT scoring, spirometry and sputum culture were analyzed. Patients with cystic bronchiectasis had higher CT score, more dilated lumen and lower forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV₁), and FEV₁/FVC than patients with cylindrical bronchiectasis. Patients with mixed ventilatory impairment had larger number of bronchiectatic segments than patients with obstructive ventilatory impairment. CT score and the number of bronchiectatic segments were significantly associated with FVC and FEV₁, while CT score and the number of emphysema segments were significantly associated with FEV₁/FVC. Twenty-one patients of 49 patients showed a positive sputum culture including 15 cases of Pseudomonas aeruginosa. The CT score was the most important predictor of lung function. The presence of air-fluid levels predicted bacterial colonization.