Table 2.

The alphabet of thoracic ultrasound lines

Type	Findings
Lung and pleural lines
A-line (reverberation)	Horizontal parallel hyperechoic linear artifact depicted at regular intervals below the pleural line
B-line (ring down artifact)	Vertical hyperechoic artifact originating from the pleural line that extend to the edge of the screen, follow the lung sliding and erase the A-lines
Z-line	Short, ill-defined vertical hyperechoic lines arising from the pleural line that do not reach the edge of the screen nor erase the A-lines nor follow the lung sliding
Comet tail artifact	Short, triangular artifact with caudal apex lines arising from the pleural line following the lung sliding without reaching the edge of the screen
Superficial lines
E-line	Vertical hyperechoic artifact arising superficial to and obscuring the pleural line and extending to the edge of the screen