What it means
Edema is extra water held in the body's tissues, the same thing that makes a sprained ankle puffy. Water looks bright on some MRI images, and on CT it changes the tissue's usual shade of gray, so radiologists can spot it. Edema is a reaction, not a disease. It shows that a tissue is irritated or injured, or that fluid is not draining away as it should.
When it matters
Mild edema after a sprain, a fall or an operation is common and usually fades as the tissue heals. The key question is the cause, so the radiologist looks at what sits at the center of the swelling. Edema in the brain or the lungs gets more attention, because swelling there can affect how the organ works. A later scan can show whether it is going away.
Questions to ask your doctor
- What is the most likely cause of the edema on my scan?
- Could the edema explain the pain or swelling I feel?
- How long does edema like this usually take to settle?
