Fig. 3
From: Lung ultrasound—a primary survey of the acutely dyspneic patient
Two different appearances of air in LUS. a A hyperehoic appearance of lung air without A-lines. b LUS appearance with A-lines (solid arrows). The distance between the A-lines (dashed arrow) is equal to that between the transducer and the pleural line (dotted arrow). A-lines, other than that indicating a strong reflector is present, have no clinical significance