Lung ultrasound in the assessment of interstitial lung disease in patients with connective tissue disease: Performance in comparison with high-resolution computed tomography.

Abstract

To investigate clinical relevance of performing lung ultrasound (LUS) in patients with connective tissue disease (CTD)-associated interstitial lung disease (ILD) in comparison with high-resolution computed tomography (HRCT). This single-centre study enrolled eligible patients with CTD-ILD from the prospective LUS registry. Total B-lines were detected by assessment at 14 sites via LUS. Forced vital capacity, diffusing lung capacity for carbon monoxide (DLCO), DLCO/alveolar volume, 6-minute walking distance, and the ILD-GAP index were used as ILD prognostic parameters. Correlations were examined using single and multiple regression analyses. Sixty-seven patients were enrolled, including 29 with idiopathic inflammatory myopathy or anti-synthetase syndrome, 25 with systemic sclerosis (SSc), 10 with rheumatoid arthritis, and 3 with mixed connective tissue disease. The total number of B-lines correlated with ILD extent on HRCT in patients with CTD-ILD (r = 0.66; P < 0.001), particularly in patients with SSc-ILD (r = 0.78; P < 0.001). Total B-lines and ILD extent on HRCT showed comparable correlations with prognostic parameters, while multiple regression analysis revealed the limited benefit of performing LUS in addition to HRCT in predicting correlations with prognostic factors. LUS serves as an alternative tool for assessing the severity and prognosis of patients with CTD-ILD.