Kerley lines are a sign

Radiologic sign

A radiologic sign is an "objective" indication of some medical fact or quality that is detected by a physician during examination of a radiograph .-Examples:*Football sign*Hampton's hump*Omental cake*Pneumatosis intestinalis...

 seen on chest radiographs with interstitial pulmonary edema

Pulmonary edema

Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...

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

Peter Kerley

Sir Peter Kerley CVO was a radiologist from Dundalk, Ireland and a graduate of University College Dublin . He spent a year training in radiology in Vienna. He obtained his M.D. from the University of Ireland, in 1939. He was Director of Radiology at the Westminster Hospital and was also affiliated...

.

Associated conditions

They are suggestive for the diagnosis of congestive heart failure

Congestive heart failure

Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...

, but are also seen in various non-cardiac conditions such as pulmonary fibrosis

Pulmonary fibrosis

Pulmonary fibrosis is the formation or development of excess fibrous connective tissue in the lungs. It is also described as "scarring of the lung".-Symptoms:Symptoms of pulmonary fibrosis are mainly:...

, interstitial deposition of heavy metal particles or carcinomatosis of the lung. Chronic Kerley B lines may be caused by fibrosis or hemosiderin

Hemosiderin

thumb|Hemosiderin image of a kidney viewed under a microscope. The brown areas represent hemosiderinHemosiderin or haemosiderin is an iron-storage complex. It is always found within cells and appears to be a complex of ferritin, denatured ferritin and other material...

 deposition caused by recurrent pulmonary oedema.

Types

Kerley A lines

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

Hilum of lung

Above and behind the cardiac impression is a triangular depression named the hilum, where the structures which form the root of the lung enter and leave the viscus. These include the pulmonary artery, superiormost on the left lung, the superior and inferior pulmonary veins, lymphatic vessels and...

 out to the periphery of the lungs. They are caused by distension of anastomotic channels between peripheral and central lymphatics of the lungs. Kerley A lines are less commonly seen than Kerley B lines. Kerley A lines are never seen without Kerley B or C lines also present.

Kerley B lines

These are short parallel lines at the lung periphery. 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. They are located peripherally in contact with the pleura, but are generally absent along fissural surfaces. They may be seen in any zone but are most frequently observed at the lung bases at the costophrenic angles on the PA radiograph, and in the substernal region on lateral radiographs. Kerley B lines are seen in Congestive Heart Failure (CHF) and Interstitial Lung Diseases (ILD).

Kerley C lines

These are the least commonly seen of the Kerley lines. They are short, fine lines throughout the lungs, with a reticular appearance. They may represent thickening of anastomotic lymphatics or superimposition of many Kerley B lines.

External links

• Kerley B lines - GPnotebook.
• An example of Kerley B - hcoa.org.
• Cardiothoracic imaging - Kerley's lines - Yale University.
• Causes of pulmonary edema - medstudents.com.br