Fundamental Radiological Findings: Air Fluid Level Over The Lung Field

OVERVIEW

This page is dedicated to covering the important radiological finding of an air/fluid level over the lung field. 

WHAT IS IT?

A air fluid level refers to the presence of both fluid and air in the same physiological compartment of the body. This page is dedicated to discussing air fluid levels that are seen in the lung fields radiologically (typically seen on a chest X-ray). 

DIFFERENTIAL DIAGNOSIS FOR THIS FINDING

When seeing a air/fluid level over the lung field, it is important to keep in mind the following possible causes of this finding:

• Pleural effusion
• Hydropneumothorax 
• Lung abscess 
• Hiatal hernia 
• Empyemas 
• Necrotic tumors 

KEY FEATURES TO LOOK FOR WHEN CHARACTERIZING THE FINDING

When seeing a air/fluid level over the lung field, there are a few important radiological features one should look at to try and characterize the finding. These features can help navigate the differential diagnosis above.

• Shape of the air/fluid level: typically levels that have a meniscus are more associated with conditions like a pleural effusion, while flat horizontal levels are characteristic of conditions like a hydropneumothorax. 

Page Updated: 03.01.2017