A-lines are bright, horizontal lines that appear at regular intervals below the pleural line on a lung ultrasound image. They are reverberation artifacts created when the ultrasound beam bounces back and forth between the transducer and the pleural surface. Seeing A-lines is generally a reassuring sign because it suggests that the lung tissue underneath is normally aerated. In emergency and critical care settings, the presence or absence of A-lines helps clinicians quickly distinguish between normal lungs and conditions like pulmonary edema or pneumothorax.
Sonography Term