Kerley B Jun 2026

In a healthy lung, the connective tissues separating the lung’s tiny lobules (interlobular septa) are too thin to be seen on an X-ray. However, when fluid or cellular debris fills these spaces, the septa thicken and become visible as . They are characterized by:

Kerley B lines are considered a sign of chronic or subacute interstitial edema. In acute pulmonary edema (like a flash pulmonary edema), you might see alveolar fluid (bat wing opacities) before these lines appear. kerley b

If you see Kerley B lines, you should immediately think . The most common driver is: In a healthy lung, the connective tissues separating

You may hear about other Kerley lines, though B is by far the most clinically useful: In acute pulmonary edema (like a flash pulmonary

While CHF is the most common cause, Kerley B lines are not 100% specific. They can also be seen in: