Lung sonoanatomy
In normal aerated lung, the bright (hyperechoic) pleura is seen inferior to the ribs and seen to “slide” with respiration. This is sometimes described as “shimmering” or “ants marching”. It requires the parietal and visceral pleura to be in contact.
A-lines are artefacts are reverberations of the pleural line caused by sound waves becoming trapped between pleura and fascial layers before returning to the transducer. The US machine interprets these delayed echoes this as being “deeper” to the probe surface. A-lines are a sign of an air interface and lost as the lung becomes less aerated.
Normal lung
Normal lung sliding with A-line pattern
B-lines (ring-down artefacts)
Pneumothorax
Pleural Effusion
Pneumonia
COVID-19
Irregular pleural line with multiple B-lines
B-lines in multiple rib spaces
Irregular pleural line with small subpleural consolidation
B-lines and subpleural consolidation