Table 1

Summary of the diagnostic criteria for the three main ultrasound signs

LUS signs	B lines	Irregularity of the pleural line	Thickening of the pleural line
Diagnostic criteria	B lines	Irregularity of the pleural line	Thickening of the pleural line
Positive diagnostic criteria	Vertical hyperechoic line, and appearing below the pleural line, and extending to the bottom of the screen without attenuation, and moving with breathing.	Horizontal hyperechoic line, and appearing below the chest wall, and having lost its regular linear contour.	Horizontal hyperechoic line, and appearing below the chest wall, and it exceeds 3 mm in its smallest thickness.
Negative diagnostic criteria	Vertical hyperechoic line interrupted before the bottom of the screen (=Z line).	Horizontal hyperechoic line appearing in the chest wall, or horizontal hyperechoic line appearing in the lung area on the US screen, or horizontal hyperechoic line with regular linear contour.	Horizontal hyperechoic line measured at 3 mm or less.
Typical images	Figure 2	Figure 3	Figure 4
Presentation of results	Sum of the number of B lines in all thoracic areas.	Yes or no for each thoracic aera.	For each thoracic area, the thickness of the pleural line is given in millimetres.