Radiographic Progression and Survival of the Different HRCT Patterns of Idiopathic Pulmonary Fibrosis.

Abstract

Introduction: Idiopathic pulmonary fibrosis (IPF) is a chronic disease with a peculiar (typical) HRCT pattern, but biopsy can demonstrate usual interstitial pneumonia in patients with atypical patterns. It is unknown how progression pattern varies among different radiographic presentations of IPF. We sought to investigate the longitudinal radiographic evolution and survival of typical and non-typical patterns.

Materials and methods: One-hundred-twenty-three patients diagnosed with IPF in 2 tertiary referral hospitals were included in the study. Longitudinal evolution of non-typical patterns was considered. The HRCT visual fibrosis score was used as a reliable evaluation tool of disease progression. HRCTs were scored by 2 senior chest radiologists with ILD expertise. The primary endpoint was the evolution of the presentation pattern to probable or typical. The secondary endpoint was lung transplant (LTx)-free survival from the time of diagnosis.

Results: Average interval between HRCTs was 16±5 months; average follow-up after the 2^nd HRCT was 17±11 months. Four out of 45 (8.9%) patients with probable pattern "evolved" to a typical pattern of IPF, while 5 out of 31 (16.1%) with indeterminate/alternative pattern "evolved" to probable pattern. An average HRCT fibrosis score increase of 9±11% was observed with typical (n=49), 6±5% with probable (n=43) and 7±8% (n=31) with indeterminate/alternative presentation pattern. LTx-free survival and lung function declines did not show any difference related to presentation HRCT patterns.

Conclusions: The evolution of a non-typical UIP pattern to a typical one is infrequent. All presentation HRCT patterns of IPF evolve in similar way and are associated with comparable survival time.[/sc].