Kerley lines

Kerley lines are a sign seen on chest radiographs with interstitial pulmonary edema.

They are thin linear pulmonary opacities caused by fluid or cellular infiltration into the interstitium of the lungs.

[1][2] They are suggestive for the diagnosis of congestive heart failure, but are also seen in various non-cardiac conditions such as pulmonary fibrosis, interstitial deposition of heavy metal particles or carcinomatosis of the lung.

These are longer (at least 2cm and up to 6cm) unbranching lines coursing diagonally from the hila out to the periphery of the lungs.

These lines represent interlobular septa, which are usually less than 1 cm in length and parallel to one another at right angles to the pleura.