Abstract
BackgroundAsbestosis and fibrotic hypersensitivity pneumonitis (FHP) are fibrotic interstitial lung diseases that develop secondary to inhalation exposure. The differential diagnosis is based on clinical evaluation of imaging findings, particularly in developing countries. We compared the imaging features between asbestosis and FHP to gain a better understanding of the differential diagnostic value of these conditions.MethodsThis comparative study included 204 patients with asbestosis and 74 patients with FHP. We compared patients’ clinical data and chest high-resolution computed tomography (HRCT) images obtained from a predesigned chart. The International Classification of HRCT for Occupational and Environmental Respiratory Diseases was used to categorize chest imaging findings in patients. Diagnostic tests were used to compare the imaging features of asbestosis and FHP.ResultsPatients with asbestosis were older and had a longer latent period until disease manifestation than those with FHP. Asbestosis was characterized by irregular and/or linear opacities, with lower lung preponderance, accompanied by ground-glass opacities and mosaic attenuation. Notably, 98.5% of patients with asbestosis showed benign pleural abnormalities, and >33% of these patients had diffuse pleural thickening with parenchymal bands and/or rounded atelectasis. Abnormalities of the mediastinal and diaphragmatic pleura were observed only in cases of asbestosis, and this finding showed high specificity for the diagnosis for asbestosis compared with that for FHP. Subpleural dots or diaphragmatic pleural abnormalities showed moderate sensitivity and high specificity for diagnosis of asbestosis compared with that for FHP. Interobserver reliability was good for evaluation of imaging findings including honeycombing, pleural calcification, lymphadenectasis, and lymph node calcification.ConclusionsHRCT-based imaging findings can distinguish between asbestosis and FHP to a certain extent, particularly with regard to subpleural dots and diaphragmatic pleural abnormalities that characterize the former.
Findings from high resolution computed tomography of the lung and pleura of symptom free workers exposed to amosite who had normal chest radiographs and pulmonary function tests.
