Kerley B Lines
🫁 Kerley Lines Overview
Kerley lines are thin linear pulmonary opacities seen on chest X-ray, usually representing interstitial edema or interstitial thickening. They are often associated with pulmonary venous hypertension, congestive heart failure, or interstitial lung disease.
Types of Kerley Lines
| Type | Appearance / Location | Clinical Associations |
|---|---|---|
| Kerley A lines | Longer (2–6 cm), radiate from hilar region toward lung periphery, usually oblique, not reaching pleura | Interstitial edema, pulmonary venous hypertension; represent centrilobular interstitial thickening |
| Kerley B lines | Short (1–2 cm), horizontal, at lung bases, perpendicular to pleura, often at costophrenic angles | Most common; seen in pulmonary venous congestion, CHF |
| Kerley C lines | Fine reticular network throughout lungs; less distinct | Severe pulmonary edema; represents superimposed Kerley B lines |
| Kerley D lines (less common, sometimes called “L lines”) | Lines at upper lobes, similar to A lines | Pulmonary edema with redistribution; rare |
Radiographic Features
- Best seen on posterior-anterior (PA) chest X-ray; lateral views may help.
- Represent interlobular septal thickening.
- Often associated with cardiomegaly, pleural effusions, or pulmonary edema.
Clinical Significance
- CHF / Pulmonary venous hypertension → most common cause.
- Interstitial lung disease → may mimic Kerley lines.
- Pulmonary lymphangitic carcinomatosis → Kerley A lines may be prominent.
- Edema grading → Presence of B lines often indicates early pulmonary congestion.
Summary Table
| Feature | Kerley A | Kerley B | Kerley C |
|---|---|---|---|
| Length | 2–6 cm | 1–2 cm | Reticular network |
| Location | Radiates from hilum | Lung bases, peripheral | Throughout lungs |
| Orientation | Oblique | Horizontal, perpendicular to pleura | Reticular |
| Common Cause | Interstitial edema, CHF | Pulmonary venous congestion | Severe pulmonary edema |
🫁 Kerley B Lines – Quick Reference
Appearance
Short (1–2 cm), thin, horizontal lines
Perpendicular to pleura at lung bases
Location
Peripheral lower lung zones, near costophrenic angles
Pathophysiology
Thickened interlobular septa due to interstitial edema
Commonly caused by pulmonary venous congestion in CHF
Clinical Significance
Most sensitive radiographic sign of early interstitial edema
Helps assess severity and response to therapy in heart failure
Imaging Tips
Best seen on PA chest X-ray
Lateral view may help for further localization
🫁 Kerley Lines – MCQs
🫁 Kerley Lines – Key Points
Kerley A
2–6 cm long, oblique lines
Radiate from hilum toward periphery
Central interstitial thickening
Kerley B
1–2 cm short, horizontal lines
At lung bases, perpendicular to pleura
Most sensitive for interstitial edema
Kerley C
Fine reticular pattern
Throughout lungs
Superimposed Kerley B lines in severe edema
Kerley D
Rare, vertical/oblique lines
Upper lobes
Associated with pulmonary venous hypertension
Kerley D
Best seen on posterior-anterior (PA) chest X-ray;
lateral views may help.
Upper lobes
Associated with pulmonary venous hypertension
