Lung ultrasound for the screening of interstitial lung disease in very early systemic sclerosis

BACKGROUND: A high percentage of patients with systemic sclerosis (SSc) develop interstitial lung disease (ILD) during the course of the disease. Promising data have recently shown that lung ultrasound (LUS) is able to detect ILD by the evaluation of B-lines (previously called ultrasound lung comets), the sonographic marker of pulmonary interstitial syndrome. OBJECTIVE: To evaluate whether LUS is reliable in the screening of ILD in patients with SSc. METHODS: Fifty-eight consecutive patients with SSc (54 women, mean age 51±14 years) who underwent a high resolution CT (HRCT) scan of the chest were also evaluated by LUS for detection of B-lines. Of these, 32 patients (29 women, mean age 51±15 years) fulfilled the criteria for a diagnosis of very early SSc. RESULTS: At HRCT, ILD was detected in 88% of the SSc population and in 41% of the very early SSc population. A significant difference in the number of B-lines was found in patients with and without ILD on HRCT (57±53 vs 9±9; p<0.0001), with a concordance rate of 83%. All discordant cases were false positive at LUS, providing a sensitivity and negative predictive value of 100% in both SSc and very early SSc. CONCLUSIONS: ILD may be detected in patients with very early SSc. The presence of B-lines at LUS examination correlates with ILD at HRCT. LUS is very sensitive for detecting ILD even in patients with a diagnosis of very early SSc. The use of LUS as a screening tool for ILD may be feasible to guide further investigation with HRCT.