Kerley B lines represent (connective tissue between secondary pulmonary lobules). Causes include:

In standard radiology literature, there is no Kerley D classification . The term “Kerley D” is occasionally misused informally to refer to subpleural edema lines or thickened septa in atypical locations , but it is not a recognized subtype. This report will therefore focus on Kerley B lines as the most relevant finding.

: They represent thickening of the anterior interlobular septa, often due to fluid (edema) or cellular infiltration (fibrosis). Clinical Significance