Diffuse Pulmonary Ossification on High-Resolution Computed Tomography in Idiopathic Pulmonary Fibrosis, Systemic Sclerosis-Related Interstitial Lung Disease, and Chronic Hypersensitivity Pneumonitis: A Comparative Study.

The aim of the study was to compare the prevalence of diffuse pulmonary ossification (DPO) in idiopathic pulmonary fibrosis (IPF), systemic sclerosis (SSc)-related interstitial lung disease (ILD), and chronic hypersensitivity pneumonitis (HP).
High-resolution computed tomography (HRCT) from 71 IPF, 67 SSc-ILD, and 75 HP cases were independently evaluated by 2 thoracic radiologists blinded to patient data. Studies were assessed for the presence of DPO, HRCT scanning pattern, stigmata of granulomatous infection, and honeycombing.
The prevalence of DPO was significantly higher in cases of IPF and SSc compared with HP, although there was no significant difference in prevalence between the IPF and SSc groups, even when accounting for the presence of prior granulomatous infection. Interobserver agreement for the presence of DPO was substantial.
Although prevalence DPO on HRCT varies between some forms of ILD, the use of DPO to influence characterization of ILD should be considered with caution.