Kerley B lines are short, thin horizontal lines (typically 1–2 cm long and <1 mm thick) seen on chest X-rays or CT scans.
They are located at the periphery of the lungs, extend to the pleural surface and most frequently appear at the lung bases in the costophrenic angles.
These lines indicate thickening of the interlobular septa within the lung, usually caused by the accumulation of fluid, cells, or fibrosis.
Most Common Causes: Pulmonary Edema: Fluid buildup resulting from congestive heart failure or elevated left atrial pressure.
Lymphangitic Carcinomatosis: The spread of cancer cells through the lymphatic channels of the lungs.
Interstitial Lung Diseases: Fibrosis, sarcoidosis, or pneumoconiosis.
Severe Pneumonia: Viral or mycoplasmal infections.
Visual CharacteristicsAppearance: Thin, distinct, unbranching white lines.
Orientation: Perpendicular to the pleural surface.
Location: Most prominent at the lower lung zones near the costophrenic angles.