Applicability of thoracic ultrasound for the assessment of patients with fibrosing interstitial lung diseases: a systematic review

Purpose: Fibrosing interstitial lung diseases (F-ILD), which include idiopathic pulmonary fibrosis (IPF) and other ILDs conferring risk for progressive pulmonary fibrosis (PPF), are a heterogeneous group of diseases with multiple subtypes. A multidisciplinary team discussion (MDD) incorporating HRCT is considered the gold standard for diagnosing and quantifying pulmonary fibrosis. However, repeated HRCTs are associated with substantial costs and radiation exposure. Thoracic ultrasound (TUS) has emerged as a potential radiation-free method for diagnosing and monitoring disease severity in F-ILD. However, consistent knowledge regarding the use of TUS in patients with F-ILD remains limited. This systematic review aimed to evaluate existing literature on the applicability of TUS in patients with F-ILD. Materials and Methods: We performed a systematic review according to PRISMA guidelines. MEDLINE, Embase, CINAHL, and Cochrane library databases were searched. Prospective, cross-sectional, and retrospective studies were considered. Risk of bias was assessed using quality assessment of diagnostic accuracy studies 2 (QUADAS-2). Results: Six studies met the inclusion criteria. All examined patients had IPF, and two had other F-ILD subtypes. The most frequently evaluated TUS findings were B-lines and pleural line irregularities (PI). However, there was marked heterogeneity in TUS methodology and protocols, precluding meta-analysis. Conclusion: Although the preliminary findings in this review suggest TUS may have potential utility in this patient group, available data on TUS in F-ILD are sparse and heterogeneous, highlighting the need for further research.