Fat stranding

3 things to know first

1. It is a CT appearance. Fat looks hazier or streakier than usual.
2. It is not one disease. Inflammation, infection, injury, or other processes can cause it.
3. Its location gives the clue. The organ and other findings determine what it may mean.

What it is

Body fat normally appears relatively dark and uniform on CT. Fat stranding describes fine lines or a hazy increase in density within that fat. It is often seen around bowel, appendix, pancreas, kidney, or other structures, but may occur elsewhere.

Why it appears on your report

The radiologist notes fat stranding because it can help locate a process. For example, stranding next to an inflamed organ may support that organ as the source of symptoms. The report should be read together with organ appearance, fluid, symptoms, and laboratory findings.

How serious is it

Fat stranding alone does not establish the cause or urgency. Mild changes may have several explanations; marked stranding with other concerning findings may need prompt care. The final impression is more useful than the phrase in isolation.

When to seek care urgently

Seek urgent assessment for severe or worsening abdominal pain, persistent vomiting, fever with significant illness, or a rigid abdomen.

What usually happens next

1. Identify where the stranding is and what structure is nearby.
2. Review accompanying CT findings and symptoms.
3. Follow the clinician's plan for observation, additional tests, or treatment.

A simple analogy

Clear packing around an object looks cloudy when disturbed. CT fat stranding is a similar visual clue that something nearby may be affecting the tissue.

Further reading

• RSNA — RadLex and imaging observations
• ACR — Appropriateness Criteria