The Ring Down Artefact: B-lines
The comet tail artefact is a commonly misused term to describe any vertical artefact seen in lung ultrasound (LUS). However there are many types of vertical artefacts with varying physical genesis and significance.
This video clip shows three vertical artefacts.
The most prominent is a ring-down artifact that is commonly called a B-line in LUS. This is seen to originate from the pleural line and actively swinging from side to side in tandem with lung sliding. B-lines are important for the diagnosis of lung disease processes that involve interstitial thickening and subpleural fluid accumulation.
As the B-lines passes to the right, two other verticals artefacts are revealed. These are called Z-lines and have a different morphology; static and without relations to the pleural line. They have no clinical signficance.
Dr. Francis Lee Chun Yue
Acute and Emergency Care Centre, Khoo Teck Puat Hospital. Singapore