The Role of Lung Ultrasound in Systemic Sclerosis: A Systematic Review.

Background: In systemic sclerosis (SSc), high-resolution computed tomography (HRCT) of the chest is the standard criterion for the diagnosis of interstitial lung disease (ILD). However, recent evidence suggests that lung ultrasound (LUS) can also detect ILD, without radiation exposure. Thus, our goal was to perform a systematic review, aiming to clarify the role of LUS in the detection of ILD in SSc.

Methods: A systematic review was carried out in PubMed and EMBASE (PROSPERO register number CRD42022293132), to identify studies that compared LUS with HRCT in the detection of ILD in patients with SSc. Risk of bias was assessed with the QUADAS-2 () tool.

Results: Three hundred seventy-five publications were identified. After screening, 13 were included in the final analysis. No study presented high risk of bias. Lung ultrasound protocol was highly heterogeneous between authors, specifically concerning transducer, intercostal spaces evaluated, exclusion criteria, and definition of positive LUS. Most authors evaluated the presence of B-lines as a surrogate of ILD, with only 4 focusing on pleural changes. A positive correlation between LUS findings and ILD detected by HRCT was reported. Results also revealed high sensitivity (74.3%-100%) but variable specificity (16%-99%). Positive predictive value varied between 16% and 95.1%, and negative predictive value between 51.7% and 100%.

Conclusion: Lung ultrasound is sensitive in the detection of ILD, but specificity must be optimized. The value of pleural evaluation also requires further investigation. Moreover, a consensus is needed to define a uniform LUS protocol to implement in future investigations.