High-Resolution CT Quantification of Bronchiectasis
Gaik C. Ooi, MRCP, FRCR ; Pek L. Khong, FRCR ; Moira Chan-Yeung, MD ; James C. M. Ho, MD, FRCP ; Philip K. S. Chan ; Jeriel C. K. Lee ; Wah K. Lam, MD, FRCP ; Kenneth W. T. Tsang, MD, FRCP
PURPOSE: To evaluate clinical relevance of high-resolution computed tomographic (CT) findings in patients with bronchiectasis by using a quantitative high-resolution CT protocol to assess extent of bronchiectasis, severity of bronchial wall thickening, and presence of small-airway abnormalities and mosaic pattern.
MATERIALS AND METHODS: Sixty Chinese patients with steady-state bronchiectasis underwent thoracic high-resolution CT and lung function tests. Exacerbation frequency per year and 24-hour sputum volume were determined. Extent of bronchiectasis, severity of bronchial wall thickening, and presence of small-airway abnormalities and mosaic attenuation were evaluated in each lobe, including the lingula. Differences between sex and smoking status with respect to high-resolution CT, lung function, and clinical parameters were tested with either the independent sample t test or the Mann-Whitney test. Spearman rank correlation was used to evaluate associations between clinical, lung function, and high-resolution CT scores. Multiple regression analyses were performed to determine which high-resolution CT parameters would best predict lung function and clinical parameters, adjusted for smoking.
RESULTS: Exacerbation frequency was associated with bronchial wall thickening (r = 0.32, P = .03); 24-hour sputum volume with bronchial wall thickening and small-airway abnormalities (r = 0.30 and 0.39, respectively; P < .05); and forced expiratory volume in 1 second (FEV1), ratio of FEV1 to forced vital capacity (FVC), and midexpiratory phase of forced expiratory flow (FEF25%-75%) (r = −0.33, −0.29, and −0.32, respectively; P < .05). Extent of bronchiectasis, bronchial wall thickening, and mosaic attenuation, respectively, were related to FEV1 (r = −0.43 to −0.60, P < .001), FEF25%-75% (r = −0.38 to −0.57, P < .001), FVC (r = −0.36 to −0.46, P < .01), and FEV1/FVC ratio (r = −0.31 to −0.49, P < .01). After multiple regression analysis, bronchial wall thickening remained a significant determinant of airflow obstruction, whereas small-airway abnormalities remained associated with 24-hour sputum volume. Women had milder disease than men but showed more high-resolution CT functional correlations.
CONCLUSION: Findings of this study establish a link between morphologic high-resolution CT parameters and clinical activity and emphasize the role of bronchial wall thickening in patients with bronchiectasis.