Role of Impulse Oscillometry (IOS) Together with Diffusing Capacity of the Lungs for Carbon Monoxide (DLCO) and High-Resolution Computed Tomography for the Chest in Early Diagnosis of Interstitial Lung Disease in Patients with Connective Tissue Disea

Abstract Background Connective Tissue Diseases (CTDs) are systemic autoimmune conditions characterized by frequent lung involvement. Interstitial lung disease (ILD) is a severe pulmonary complication in CTD and associated with significant increased morbidity and mortality, so early detection of ILD is essential. Aim of the Work To find the best modality for early diagnosis of interstitial lung disease in patients with connective tissue disorders by using DLCO, impulse oscillometry and HRCT chest. Patients and Methods This observational, analytical and cross sectional study was conducted upon 60 patients whom were diagnosed as connective tissue disease during the period from march 2022 to march 2023 who were admitted to chest and rheumatology department or outpatient clinics visitors, to Ain Shams University Hospitals. Results regarding our results, there was high statistical significance between DLCO and IOS (Best x5). Sensitivity and specificity of Diffusion lung of CO2; DLCO score in prediction of outcome in CT Chest Findings showing significance in DLCO score; p = 0.024 with CI ranged between 53.9-81.4% and sensitivity 67.6%. Sensitivity and specificity of the impulse oscillation method; R5, R20,and Best-X5 score in prediction of outcome in CT Chest Findings. Showing no significance in all with sensitivity 50.2%, 46.1%, 43.4% and 57.5% respectively Conclusion ILD should always be considered in patients with CTD. Diagnosis of CTD-ILD is challenging so Early diagnosis of ILD using DLCO, HRCT chest or by using IOS is important as it could affect therapy plans.