Abstract: Objective To evaluate the difference and the diagnostic value of high-resolution CT (HRCT)findings in patients with idiopathic pulmonary fibrosis(idiopathic pulmonary fibrosis,IPF)and connective tissues disease-interstitial lung disease( connective tissues disease-interstitial lung disease, CTD-ILD). Methods Seventeen patients with IPF and 36 patients with CTD-ILD scanned by HRCT were reviewed retrospectively. Statistical analysis was conducted in ground-glass opacity and consolidation,honeycombing,interlobular interstitial thickening,traction bronchiectasis,subpleural curve and interlobular septal thickening,pleural thickening,pleural effusion and meditational lymph node enlargement. Results Honeycombing was the predominant pattern(64. 7%)in IPF,while CTD-ILD only accounted for 16 . 7%( P =0 . 003 ). Ground-glass opacity and consolidation was the predominant pattern in CTD-ILD(72. 2%),while IPF accounted just for 29. 4%(P=0. 000). Traction bronchiectasis was 41. 2% in IPF,but 13. 9% in CTD-ILD(P=0. 027). Conclusion Although HRCT findings of IPF and CTD-ILD are similar and overlap considerably,but patients with IPF showed a tendency to more progressed fibrosis than patients with CTD-ILD.

Key words: idiopathic pulmonary fibrosis, lung diseases, interstitial, diagnnosis differential