High-resolution computed tomography in idiopathic pulmonary fibrosis: Diagnosis and prognosis

Rationale: High-resolution computed tomography (HRCT) is an integral aspect of the evaluation of patients with suspected idiopathic pulmonary fibrosis (IPF). However, few studies have evaluated its use in a large cohort. Objectives: To describe HRCT features in patients with mild to moderate IPF, compare diagnostic evaluations by a radiology core (three thoracic radiologists) with those by studysite radiologists, correlate baseline clinical and physiologic variables with HRCT findings, and evaluate their association with mortality. Methods: We assessed HRCT scans from patients with IPF (n = 315) enrolled in a randomized controlled study evaluating IFN-gamma 1b. Measurements and Main Results: There was concordance between study-site and core radiologists regarding the diagnosis of IPF in 86% of cases. Diffusing capacity of carbon monoxide (DLCO) was the physiologic characteristic most highly correlated with HRCT findings. Multivariate analysis identified three independent predictors of mortality: a higher extent of fibrosis score increased the risk of death (p < 0.0001), whereas a higher percent-predicted DLCO (p = 0.004) and treatment assignment to IFN-gamma 1b rather than placebo (p = 0.04) reduced the risk of death. Conclusions: A study-site diagnosis of IPF on HRCT was regularly confirmed by core radiologists. Extent of reticulation and honeycombing on HRCT is an important independent predictor of mortality in patients with IPF.