Air trapping in usual interstitial pneumonia pattern at CT: prevalence and prognosis.

This study was conducted to evaluate the presence of air trapping in patients with idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs) (non-IPF), showing the radiological pattern of usual interstitial pneumonia (UIP). Retrospectively, we included 69 consecutive patients showing the typical UIP pattern on computed tomography (CT), and 15 final diagnosis of IPF with CT pattern "inconsistent with UIP" due to extensive air trapping. Air trapping at CT was assessed qualitatively by visual analysis and quantitatively by automated-software.