The Role of Ultrasound Pleural Irregularities in the Identification of Interstitial Lung Disease in Idiopathic Inflammatory Myopathies

<b>Background</b>: Interstitial lung disease (ILD) is the most frequent extra-muscular manifestation in patients with idiopathic inflammatory myopathies (IIMs). Although high-resolution chest tomography (HRCT) represents the gold standard for the evaluation of ILD, lung ultrasound (LUS) might be a useful tool for its assessment. The aim of our study was to evaluate the number and distribution of pleural irregularities (PIs) identified by lung US in a cohort of patients with IIMs and to find possible correlations with clinical, serological and HRCT data to verify the potential usefulness of lung US for the study of ILD in patients with IIM. <b>Patients and methods</b>: Fifty-three patients with IIM according to EULAR/ACR classification criteria were enrolled. All patients underwent a clinical evaluation with measurement of disease activity and myositis-specific autoantibodies, pulmonary function tests, HRCT evaluated with the Warrick score, and lung US for the measurement of PIs. <b>Results</b>: The number of PIs was higher in patients with myositis-specific autoantibodies, particularly those with anti-synthetase autoantibodies (<i>p</i> < 0.001) and in patients with high-grade dyspnea (<i>p</i> < 0.03). A negative correlation was identified between PIs and pulmonary function tests, particularly TLC (r = -0.74; <i>p</i> < 0.001) and DLCO (r = -0.56; <i>p</i> < 0.001). Interestingly, PI score was higher in patients with ILD identified with HRCT (<i>p</i> = 0.015) and a positive correlation between PIs and Warrick score (r = 0.542; <i>p</i> < 0.001) was also found. <b>Conclusions</b>: The study of PIs with lung US represents a promising diagnostic tool for the bedside evaluation of patients with IIMs. This can possibly allow for a reduction in unnecessary HRCTs, reducing the exposition of patients to ionizing radiations, optimizing resources and reducing the costs of patients' management.