Usual Interstitial Pneumonia: Typical and Atypical High-Resolution Computed Tomography Features

The computed tomography appearances of usual interstitial pneumonia (UIP) are usually characteristic, with basal-predominant, peripheral-predominant reticular abnormality and honeycombing. Important complications that may be detected by the radiologist include pulmonary hypertension, lung cancer, and acute exacerbation. As the number of surgical lung biopsies performed for typical UIP declines, histologic findings of UIP are increasingly found in subjects with atypical computed tomographic features. Potential reasons for such discordance may include variability in pathologist interpretation, sampling error on biopsy, biopsy obtained from nonrepresentative site, coexistence of multiple pathologies within the same lung, and familial pulmonary fibrosis. Multidisciplinary diagnosis is critical in resolving these cases.