Kerley lines are a sign seen on chest radiographs with interstitial

pulmonary edema Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due t ...

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

Associated conditions

They are suggestive for the diagnosis of

congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

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

pulmonary fibrosis Pulmonary fibrosis is a condition in which the lungs become scarred over time. Symptoms include shortness of breath, a dry cough, feeling tired, weight loss, and nail clubbing. Complications may include pulmonary hypertension, respiratory failu ...

, interstitial deposition of heavy metal particles or

carcinomatosis Carcinosis, or carcinomatosis, is disseminated cancer, forms of metastasis, whether used generally or in specific patterns of spread. Usage Carcinomatosis is often restricted to tumors of epithelial origin, adenocarcinomas, while sarcomatosis desc ...

of the lung. Chronic Kerley B lines may be caused by fibrosis or

hemosiderin Hemosiderin image of a kidney viewed under a microscope. The brown areas represent hemosiderin Hemosiderin or haemosiderin is an iron-storage complex that is composed of partially digested ferritin and lysosomes. The breakdown of heme gives rise ...

deposition caused by recurrent

Types

Kerley A lines

These are longer (at least 2cm and up to 6cm) unbranching lines coursing diagonally from the hila 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. Chest radiograph of a lung with Kerley B lines - annotated

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 The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips b ...

. 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. Causes of Kerley B lines include pulmonary edema, lymphangitis carcinomatosa and malignant lymphoma, viral and mycoplasmal pneumonia, interstitial pulmonary fibrosis, pneumoconiosis, and sarcoidosis. They can be an evanescent sign on the chest x-ray of a patient in and out of heart failure.

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.

References

External links

Kerley B lines
- GPNotebook

- FPNotebook
Kerley B lines image
- catscanman.net

- medstudents.com.br
Kerley's A, B, and C lines
- Images in Clinical Medicine, New England Journal of Medicine website.

- Swimming Induced Pulmonary Edema - MedPix Database {{Radiologic signs Radiologic signs