Serial High-Resolution Computed Tomography Findings of Acute and Chronic Hypersensitivity Pneumonitis Induced by Avian Antigen

Purpose: The purpose of this study was to evaluate serial changes and the prognostic value of high-resolution computed tomographic (HRCT) findings in hypersensitivity pneumonitis (HP). Method: The medical records of 112 patients with bird-related HP (17 acute, 33 recurrent, and 62 insidious) were retrospectively reviewed. High-resolution computed tomographic findings at the time of diagnosis and at follow-up were retrospectively interpreted. Results: Ground-glass opacities and centrilobular nodules were predominant findings in acute and recurrent HP, whereas honeycombing was the outstanding feature in insidious HP. Areas of ground-glass opacities and centrilobular nodules decreased in all groups over a long-term follow-up. Areas of honeycombing, on the other hand, increased in chronic HP, especially in the insidious cases. Cox regression models revealed a higher mortality risk in cases with airspace consolidation and honeycombing on HRCT. Conclusion: Acute, recurrent, and insidious HP all have characteristic features on CT. Characteristic HRCT findings can predict the prognosis of chronic HP.