Diagnostic Accuracy of X-Ray Chest for the Diagnosis of Interstitial Lung Disease Keeping High Resolution Computed Tomography Chest as Gold Standard

Abstract

Background: Interstitial lung disease (ILD) comprises a heterogeneous group of diffuse parenchymal lung disorders in which early and accurate detection is critical for prognosis and management. Although high-resolution computed tomography (HRCT) is the reference imaging modality, chest radiography (CXR) remains the most accessible first-line investigation in resource-constrained settings, and its diagnostic performance requires contextual evaluation. Objective: To determine the diagnostic accuracy of chest radiography for detecting ILD using HRCT as the reference standard in adults with clinical suspicion of ILD. Methods: This cross-sectional diagnostic accuracy study included 108 consecutive patients aged 18–75 years presenting to a tertiary-care radiology department from January to December 2024. All participants underwent standardized CXR followed by HRCT within two weeks. CXR findings were interpreted independently and blinded to HRCT results. Sensitivity, specificity, predictive values, likelihood ratios, diagnostic odds ratio, and 95% confidence intervals were calculated using a 2×2 contingency table. Results: HRCT confirmed ILD in 60 of 108 patients (55.56%). CXR demonstrated a sensitivity of 90.0% (95% CI 79.9–95.3) and specificity of 87.5% (95% CI 75.3–94.1), with positive and negative predictive values of 90.0% and 87.5%, respectively. Overall diagnostic accuracy was 88.89% (95% CI 81.6–93.5), with LR+ of 7.2 and LR− of 0.11. Conclusion: Chest radiography exhibits high diagnostic performance in clinically suspected ILD within a tertiary-care cohort; however, given residual false-negative cases, HRCT remains essential for definitive diagnosis and disease characterization.