Lung Ultrasound as a Screening Method for Interstitial Lung Disease in Patients With Systemic Sclerosis

Background Patients with systemic sclerosis (SSc) undergo chest radiographs and high-resolution computed tomography (HRCT) of the thorax both for interstitial lung disease (ILD) detection and for disease progression monitoring. Objective The aim of this study was to assess whether lung ultrasound (LUS) is a useful screening tool for ILD in patients with SSc in comparison with HRCT. Methods This was a longitudinal cohort study carried out from December 2015 to April 2016. An LUS was performed to examine B-lines in 67 consecutive patients who met the 2013 American College of Rheumatology/European League Against Rheumatism classification criteria for SSc and had a previous HRCT. B-lines were quantified and classified according to the score modified from Picano. Severity and extent of lung involvement on the HRCT were determined by means of the Warrick score. Results Twenty-nine patients had both abnormal HRCT (Warrick score >7) and abnormal LUS, 2 had a mild score (6-15 B-lines), and 27 had either moderate or severe scores (>= 16 B-lines). Of the 38 patients with negative HRCT, 25 presented some degree of lung involvement on the LUS. Thus, LUS has a sensitivity of 100% and a specificity of 34%. Receiver operating characteristic curve analysis showed the analytic relation between the number of B-lines and the presence of ILD on the HRCT (area under the curve, 0.80; 95% confidence interval, 0.69-0.90). Conclusions Lung ultrasound may be a method to detect abnormal lung findings in a noninvasive manner in patients with SSc. Because of its high sensitivity, a low score almost rules out the need for an HRCT.