Correlation Between HRCT Findings, Pulmonary Function Tests And Bronchoalveolar Lavage Cytology In Idiopathic Pulmonary Fibrosis

ObjectiveIdiopathic pulmonary fibrosis (IPF) is a sort of representative disease in the interstitial lung disease. The most regular means of clinical examination are high - resolution CT scan, pulmonary function tests and bronchoalveolar lavage. These examination means are different approaches that are expected to provide clinically relevant information about anatomy morphology, pulmonary function and cytology. HRCT is the best means of providing pulmonary microstructure and strongly associated with pathologic diagnosis. The purpose of study is to recognize the HRCT findings and evaluate the correlation between HRCT findings, pulmonary function tests and bronchoalveolar lavage cytology in IPF.Material and Method31 cases were enrolled according to the international diagnostic criterion of IPF. 69 HRCT were acquired on multisection CT in supine position. The scans were obtained during breath holding after inspiration. Within a time period of ± 3days from first CT, all patients underwent pulmonary function tests. 26 of 31 patients underwent fibroptic bronchoscopy and BAL within a time period of ± 5days from first CT. 14 patients were followed up HRCT scan during one year. The primary HRCT findings were recoded including ground - glass opacities, re-ticular pattern, interlobular septal thickening, interlobular interstitial thickening, honeycombing and enlarged mediastinal lymph nodes. The observer gaveCT score according to the primary findings distribution in the lung, including ground - glass opacities, reticular pattern and honeycombing. The pulmonary function parameters adjusted by age, sex, height and body mass index, including FVC, FEV1, FEV1/FVC, TLC, DLco and PaO2. The cells of BALF are recorded including alveolar macrophage, neutrophil , lymphocyte and eosino-phils. All the data of HRCT scores , pulmonary function parameters and BALF cell counts were statistical analysed by SPSS. The results were expressed as x ± s, Smoking/non - smoking groups were compared with t - test and Mann - Whitney test. Flow -up groups were compared with ANOVA. Agreement or discordance of HRCT, PET and BAL were analysed with Spearmans correlation, p <0. 05 were defined as threshold for statistical differences and p <0.01 were significant differences.ResultThe primary HRCT findings were reticular pattern (96. 8% ) , interlobular septal thickening(90. 3% ) , interlobular interstitial thickening (58. 1% ) , honeycombing (74. 2% ) , enlarged mediastinal lymph nodes (48. 4% ) , ground -glass opacities(41.9% ). Besides, the other findings were often appeared, including subpleural line and micronodules. The most of lesion were showen in the lower lung fields and distributed in the peripheral areas. The CT score of follow - up patients showed no significant difference from that of first examination. Ground - glass opacities were weak but significantly negatively correlated with FEV1 and FEV1/FVC. The significant negative correlation were found between reticular pattern and DLco. Honeycombing and CT score were significantly negatively correlated with FVC^FEVUTLC $1 DLco. PaO2 were significantly negatively correlated with ground - glass opacities and CT score. The results of BAL fluid varied over a wide range. The average values for neutropil, lymphocyte and eosinophis were 12.0% ( ±9. 8% ) , 8.7% ( ± 6. 0% ) , 1. 9% ( ± 2. 8% ) respectively, higher than the results of our laboratory. Neutropil counts were slightly positively correlated with ground - glass opacities. Eosinophis were slightly positively correlated with reticular pattern and CT score.Conclusion1. HRGT is the best means without any hurting for idiopathic pulmonary fi-brosis in clinical examination. Of all the manifestations, The reticular pattern and/or honeycombing are significant for diagnosis.2. There are significant correlations between HRCT findings and pulmonary function parameters. Ground - glass opacities is a finding to reflect the pulmonary ventilation abnormality. Reticular pattern reflect the pulmonary diffusion abnormality. Honeycombing reflect the pulmonary function both ventilation abnormality and diffusion abnormality. The CT score can reflect the pulmonary function changes.3. Ground - glass opacities were slightly positively correlated with neutropil counts . Reticular pattern and CT score were slightly significantly positively correlated with eosinophis.