Computed Tomography Findings in Pathological Usual Interstitial Pneumonia

TLDR

Patients with idiopathic pulmonary fibrosis often show typical or atypical usual interstitial pneumonia patterns on CT, including findings common in nonspecific interstitial pneumonia. The study aimed to reassess high‑resolution CT findings in IPF and determine how these patterns correlate with mortality. Two observers independently classified each CT scan as definite UIP, consistent with UIP, or suggestive of an alternative diagnosis, and the resulting categories were correlated with survival using Kaplan–Meier, log‑rank, and Cox regression analyses. Survival did not differ significantly among the three CT categories (45.7, 57.9, and 76.9 months, P > 0.05), but traction bronchiectasis and fibrosis scores were significant predictors of outcome, with hazard ratios of 1.30 and 1.10, respectively.

Abstract

Patients with a clinicopathological diagnosis of idiopathic pulmonary fibrosis (IPF) may have typical findings of usual interstitial pneumonia (UIP) on computed tomography (CT) or nonspecific or atypical findings, including those often seen in nonspecific interstitial pneumonia.The aims of this study were to revisit the high-resolution CT findings of IPF and to clarify the correlation between the CT findings and mortality.The study included 98 patients with a histologic diagnosis of UIP and a clinical diagnosis of IPF. Two observers evaluated the CT findings independently and classified each case into one of the following three categories: (1) definite UIP, (2) consistent with UIP, or (3) suggestive of alternative diagnosis. The correlation between the CT categories and mortality was evaluated using the Kaplan-Meier method and the log-rank test, as well as Cox proportional hazards regression models.Thirty-three of the 98 CT scans were classified as definite UIP, 36 as consistent with UIP, 29 as suggestive of an alternative diagnosis. The mean survival was 45.7, 57.9, and 76.9 months, respectively. There was no significant difference in survival among the three categories (all P > 0.05). Trction bronchiectasis and fibrosis scores were significant predictors of outcome (hazard ratios: 1.30 and 1.10, respectively; 95% confidence intervals: 1.18-14.2 and 1.03-1.19, respectively).In patients with IPF and UIP pattern on the biopsy, the pattern of abnormality on thin-section CT, whether characteristic of UIP or suggestive of alternative diagnosis, does not influence prognosis. Prognosis is influenced by traction bronchiectasis and fibrosis scores.