This high-frequency ultrasonogram was obtained from a patient with severe mitral stenosis who presented with pulmonary oedema. This high-frequency ultrasonogram was obtained from a patient with severe mitral stenosis who presented with pulmonary oedema. Note the widespread B-lines (B), a reliable sign of interstitial pulmonary oedema, as well as the associated small pleural effusion (PE). Florian von Groote-Bidlingmaier, and Coenraad F.N. Koegelenberg breathe 2012;9:132-142 ©2012 by European Respiratory Society