Objectives: To evaluate a new ultrasound sign, pleural irregularity (PI), for the study of interstitial lung disease (ILD) in patients with systemic sclerosis (SSc) and antisynthetase syndrome (ASS).
Methods: The study included patients from our SSc and ASS cohorts with varying degrees of ILD, enrolled from 2011 to 2014. Chest high-resolution computed tomography (HRCT), pulmonary function tests (FVC and DLCO) and chest sonography were performed in each patient. Ultrasound PI and B-lines were quantified using a 72-sonographic point score and HRCT lung abnormalities were quantified using Warrick and Wells scores and categorised through Goh's algorithm. PI was correlated with HRCT and pulmonary function test parameters and its diagnostic performance to detect and classify the extent of ILD was evaluated and compared with B-lines.
Results: Thirty-seven patients were studied, 21 with ASS and 16 with SSc (8 without ILD). PI correlated with the Warrick score both in SSc (r=0.6, p=0.01) and ASS patients (r=0.6, p=0.005), showing a higher performance to detect ILD than using B-lines (p=0.01). In SSc patients PI also correlated with Wells score (r=0.7, p<0.001) and with DLCO (r=-0.5, p=0.05), showing a high diagnostic value for detecting ILD (AUC=0.85, 95% CI 0.64-1) and classifying it into limited or extensive (AUC=0.81, 95% CI 0.57-1). A modification of the Goh algorithm including PI was developed as a screening tool to avoid the use of HRCT in SSc patients without ultrasound evidence of extensive ILD.
Conclusions: PI is useful for evaluation of ILD in SSc and ASS patients, and can be incorporated into a diagnostic algorithm in SSc patients to reducing the need for exposure to ionising radiation.