If you’ve ever looked at a chest X-ray and seen a cluster of tiny, horizontal lines at the lung bases, you might have dismissed them as blood vessels or artifact. But to a trained eye, those little lines are a major red flag. They are called Kerley B lines , and they are one of the most classic signs of an overworked heart and fluid-filled lungs.
Next time you scroll through a CXR, don’t just look at the lung fields for pneumonia. Zoom in on those peripheral lower zones. If you see a row of short, horizontal lines—think and B for “Back to the chart to check for heart failure.” Have you missed Kerley B lines before? What’s your go-to sign for early interstitial edema? Let me know in the comments below. kerley b
Let’s break down what these lines are, why they appear, and why radiologists get concerned the moment they spot them. In simple terms, Kerley B lines are thin, linear opacities seen in the periphery of the lungs, most commonly near the costophrenic angles (the bottom corners of the lungs). If you’ve ever looked at a chest X-ray
When pressure in the pulmonary capillaries rises (e.g., due to heart failure), fluid leaks out of the vessels. Gravity pulls this fluid into the most dependent parts of the lung—the lower zones. The fluid accumulates in the interstitial space, specifically thickening those interlobular septa. Next time you scroll through a CXR, don’t