Evaluation of high-resolution computed tomography findings and associated factors in hypersensitivity pneumonitis

Abstract

Background/Aim: Hypersensitivity pneumonitis (HP) is a lung disease from inhaling diverse environmental and occupational organic substances, such as fungi, bacteria, birds, and occasionally nonorganic materials. An immune response triggers this condition. A high-resolution chest computed tomography (HRCT) scan is typically performed as part of the initial diagnostic assessment. This study assesses HRCT findings in HP patients and examines associated factors between fibrotic and non-fibrotic patient groups. Methods: This retrospective cross-sectional study encompassed all HP patients monitored between 2010 and 2022. The analysis included data from 117 patients. HRCT findings from the patients were categorized based on fibrosis presence, leading to the division of patients into fibrotic and non-fibrotic groups. Comparative analyses were conducted between these groups. Results: Among the 117 subjects analyzed, 59 (50.4%) were male, and 58 (49.6%) were female. The mean age at diagnosis was 52.1 (13.6) years, ranging from 20 to 81. The non-fibrotic HP group comprised 70 (59.8%) patients, while the fibrotic HP group comprised 47 (40.2%). The most prevalent HRCT findings were ground-glass opacity (90.6%), mosaic attenuation (87.2%), and traction bronchiectasis (50.4%). Statistically significant disparities were observed between non-fibrotic and fibrotic HP groups in terms of HRCT findings: ground-glass opacity, irregular linear opacities, reticulation, traction bronchiectasis, honeycombing, and fibrosis (P=0.024, P<0.001). In contrast, the lymphocyte ratio in bronchoalveolar lavage fluid was 28.78 (16.2) in the non-fibrotic HP group and 14.66 (10.3) in the fibrotic HP group. The fibrotic HP group exhibited a statistically significant lower lymphocyte ratio in bronchoalveolar lavage fluid (P<0.001). Conclusion: HRCT findings are pivotal in HP diagnosis and classification. Computed tomography also assists in delineating the HP classification. This study identified ground-glass opacity and mosaic attenuation as the most prevalent HRCT findings in HP patients. Investigating the connection between fibrosis and prognosis is vital for determining patient outcomes, as fibrosis appears to be the principal determinant.