Interstitial lung disease misdiagnosis with cardiac pulmonary congestion: a prospective study of misclassification and predictive imaging markers

Abstract Background Interstitial lung disease (ILD) and cardiac pulmonary congestion often present with overlapping clinical and radiological features, leading to frequent diagnostic challenges. Accurate differentiation during the acute worsening of the ILD worsening is essential to guide appropriate management. Objective To determine the frequency of pulmonary congestion misinterpretation as ILD based initially on HRCT interpretation alone and to identify particular HRCT findings that are more frequently related with correct diagnosis of ILD. Methods A prospective cross sectional study was conducted on 66 patients initially diagnosed with ILD based on HRCT radiological reports. All patients had their HRCT scans re-evaluated by multidisciplinary team comprising one radiologist and two pulmonologist furthermore during an exacerbation of the ILDTrans thorthac echocardiography was performed for all patients. The final diagnosis was established through multidisciplinary discussion (MDD), integrating the clinical presentation, HRCT findings, cardiac/echocardiographic assessment, and clinical course. The diagnostic agreement between the first and the final diagnoses was evaluated using kappa analysis. Logistic regression was utilized to find predictors for pulmonary congestion diagnosis. Results A significant proportion of patients initially diagnosed with ILD were later reclassified after radiological reassessment and incorporation of echocardiographic data. Only 59.1% confirmed as ILD, 34.8% as cardiac congestion, and 6.1% mixed ILD and cardiac congestion. Regarding the HRCT findings associated with diagnostic accuracy, our results suggest that specific radiological patterns and their distribution were more informative than individual parenchymal abnormalities. In particular, the presence of honeycombing, traction bronchiectasis/bronchiolectasis, and a basal and subpleural distribution of reticular abnormalities were important features associated with correct recognition of ILD. Kappa analysis showed weak agreement between initial and final diagnoses (kappa = 0.3), indicating a notable rate of misdiagnosis. Conclusion Misdiagnosis between ILD and cardiac congestion is common due to overlapping imaging features. Multidisciplinary discussion including echocardiographic assessment with specific radiological feature can increase diagnostic accuracy and prevent improper treatment. Trial registration NCT06198608