: The most common type. They are short (1–2 cm), thin (
Kerley B lines are short, horizontal lines at the lung periphery, typically seen at the costophrenic angles. They represent interstitial edema and are often associated with: septal lines on chest x ray
"Lung fields: There are bilateral Kerley B lines, suggestive of interstitial edema. The lungs are otherwise clear. : The most common type
Pleura: No significant effusion.
Septal lines in lung | Radiology Reference Article - Radiopaedia The lungs are otherwise clear
These lines are a result of the thickening of the interlobular septa due to fluid accumulation or fibrosis. The presence of septal lines on a chest X-ray suggests that there may be an underlying condition affecting the lung interstitium.
In a patient with acute dyspnea, almost always point to elevated left atrial pressure (e.g., congestive heart failure), often appearing before overt alveolar edema (i.e., before diffuse airspace opacities). Their presence helps distinguish cardiogenic from noncardiogenic pulmonary edema (e.g., ARDS) – though not absolute, septal lines are much more common in cardiogenic causes.