Bronchiectasis with decreased attenuation areas on HRCT: correlation with pulmonary function test

To evaluate the relationship between type, extent, and associated decreased attenuation areas of bronchiectasis, as seen on high-resolution CT (HRCT), and abnormalities on pulmonary function tests. We retrospectively evaluated 34 patients with bronchiectasis, in whom inspiratory and expiratory HRCT scans and pulmonary function tests were performed. HRCT scans were reviewed for the type (cylindrical vs. cystic) and extent of bronchiectasis (number of segments), and the extent of decreased attenuation areas seen on inspiratory (number of segments and CT scores) and expiratory scans (CT scores). With regard to the type and extent of bronchiectasis and the extent of decreased attenuation areas, as seen on HRCT, three radiologists reached a consensus. We evaluated the relationship between pulmonary function tests (FEV1, FVC, FEV1/FVC, MMEF) and HRCT findings using Pearson correlation coefficients and linear regression (PC-SAS). In all patents with bronchiectasis there were areas of decreased attenuation, as seen on inspiratory and expiratory HRCT. The extent of bronchiectasis showed strong positive correlation with the extent of decreased attenuation seen on inspiratory and expiratory HRCT (p<0.001). On pulmonary function tests, the extent of bronchiectasis and decreased attenuation correlated negatively with FEV1, FVC, FEV1/FVC and MMEF. Cystic bronchiectasis tended to be more extensive than the cylindrical variety (12.2 vs 7.6), and showed larger areas of decreased attenuation on inspiratory (number of segments: 14.4 vs 7.8; CT score: 34.7 vs 15.6) and expiratory scans (CT score: 38.1 vs 19.1). There is significant correlation between the extent of morphologic abnormality, as seen on HRCT, and the physiologic impairment of pulmonary function tests in patients with bronchiectasis and associated decreased attenuation areas