Kerley B lines are linear opacities seen on the chest radiograph. They are 1-2 cm long horizontal lines which meet the pleura at right angles. They are typically seen as a ladder up the side of the lungs beginning at the costophrenic angle.
Kerley B lines represent interlobular lymphatics which have been distended by fluid or tissue.
Kerley B lines are usually an indication of raised pulmonary venous pressure due to:
- left ventricular failure
- mitral stenosis
Other causes include:
- lymphangitis carcinomatosa
- pulmonary fibrosis
- parasitic infection