B-lines are laser-like, hyperechoic vertical artifacts that arise from the pleural line and extend to the far edge of the ultrasound image without fading. They move with respiration and erase A-lines where they appear. The presence of B-lines indicates that the lung tissue beneath the pleura contains fluid, as in pulmonary edema, pneumonia, or interstitial lung disease. A few isolated B-lines can be normal, especially at the lung bases, but three or more B-lines in a single view between two ribs is considered abnormal. Point-of-care lung ultrasound using B-lines has become an essential tool in emergency departments and intensive care units for rapidly assessing patients with shortness of breath.
Sonography Term