Pleural effusion is a buildup of fluid between the layers lining the lungs and chest wall.
Symptoms can include shortness of breath, chest discomfort, cough, reduced exercise tolerance, or sometimes no symptoms if the fluid amount is small.
Imaging helps confirm that fluid is present, show how much there is, and guide drainage when doctors need to test or relieve it.
Chest X-ray, ultrasound, and CT can help show the fluid, estimate how much is present, and guide drainage when needed.
Treatment may involve removing the fluid and addressing the cause, such as heart failure, infection, cancer, or inflammation.
This entry explains the finding. The next step is having a radiologist interpret your specific scan, not a general definition.