Development and Assessment of Novel Lung Ultrasound Interpretation Criteria for the Detection of Interstitial Lung Disease in Systemic Sclerosis

Objective Interstitial lung disease (ILD) is a frequent complication of systemic sclerosis (SSc), and ILD screening, characterization, and monitoring are important for therapeutic decision-making and prognostication. Lung ultrasonography (US) is a potential alternative imaging modality for ILD detection. In this study, our objective was to develop and test a novel lung US examination technique and interpretation criteria for detecting SSc-ILD. Methods Lung US acquisition was performed by collecting short US movies at 14 lung positions. Lung US interpretation criteria for SSc-ILD detection focused on visualized pleural changes. To assess the performance of our methodology for SSc-ILD detection, we prospectively enrolled SSc patients with high-resolution computed tomography (HRCT) imaging within 3 months of lung US. Lung US examinations were scored independently by 2 blinded readers (1 ultrasonographer and 1 nonultrasonographer). The sensitivity and specificity for SSc-ILD detection were assessed, and agreement was measured with Cohen's kappa statistic. Results To test the performance of our lung US acquisition technique and interpretation criteria, 20 SSc patients were evaluated by lung US (278 lung zones) and HRCT. HRCT confirmed ILD in 9 patients (45%). Lung US was positive for SSc-ILD in 11 patients (55%) with a sensitivity of 100% and specificity of 82% versus HRCT, with perfect agreement between the 2 readers (kappa = 1). Analysis by individual lung zones found excellent agreement between readers, with 93.8% concordance and kappa = 0.82. Conclusion We developed a novel lung US examination technique and interpretation criteria that are highly sensitive and specific for SSc-ILD detection in an SSc cohort, affording perfect agreement between ultrasonographer and nonultrasonographer readers.