Signs and lines in lung ultrasound

Point-of-care ultrasound has become firmly established in acute and critical care settings, and is now increasingly being used as an important tool in the assessment of the lungs. In this article, we briefly describe the technique of lung ultrasound and the various lines and signs commonly encountered during sonography of the lung, namely the normally visualised A- and T-lines and the bat sign, sliding sign (power slide sign on colour Doppler), sea-shore sign, curtain sign, and the lung pulse. We have also described signs seen in various pathological conditions like B-lines seen in cases of increased lung density; the quad sign, sinusoid sign, thoracic spine sign, plankton sign and the jelly fish sign seen in pleural effusion; the stratosphere sign and the lung point sign seen in pneumothorax; the shred/fractal sign and tissue-like sign in consolidation, and the double lung point sign seen in transient tachypnoea of the newborn. With adequate and appropriate training, lung ultrasound can be effectively utilised as a point-of-care investigation.