Lung ultrasound B-lines in systemic sclerosis: cut-off values and methodological indications for interstitial lung disease screening

Objectives. Lung utrasound (LUS), through assessment of B-ines and peura ine aterations, is abe to evauate interstitia ung disease (ILD), a frequent compication of SSc. Different scanning schemes and counting methods have been proposed but no cear cut-off vaues have been indicated for screening. We aimed to evauate the accuracy of different LUS methodoogica approaches to detect ILD compared with high-resoution CT (HRCT) as the god standard. Methods. Sixty-nine SSc patients underwent LUS and chest HRCT on the same day. Both exams were scored by expert readers. The accuracy of different scanning schemes and counting methods was assessed and cinica and functiona data were compared with imaging findings. Results. B-ines were more numerous in patients with the diffuse skin subset and Sc70 autoantibody positivity. The number of B-ines correated with the Sceroderma Lung Study (SLS) I HRCT score (R = 0.754, P < 0.0001). A tota of >10 B-ines on the whoe chest or >1 B-ine on the postero-basa chest showed 97% sensitivity for detecting even very eary ILD signs (corresponding to an SLS I score of 1). Sensitivity increased to 100% when peura ine aterations were incuded in the anaysis. Conclusions. LUS has a very high sensitivity in detecting SSc-reated ILD. A cut-off vaue of >10 B-ines on the whoe chest or >1 B-ine on the postero-basa chest can be used for the screening of SSc-ILD. Assessing ony the postero-basa chest seems to be mosty effective, combining high sensitivity with a ess time-consuming approach.