Fat stranding: Meaning in a Radiology Report

Also written as: stranding, fat haziness, inflammatory stranding, dirty fat sign

Fat stranding means hazy, streaky lines in the fat around an organ on CT. It usually signals inflammation nearby.

What it means

Normal fat looks smooth and evenly dark on CT. When a nearby organ is inflamed, fluid and swelling seep into the fat and show up as hazy, gray streaks. Radiologists call this fat stranding. It is a useful clue, because it often points to exactly where the trouble is, such as an inflamed appendix, gallbladder or small pouch in the colon wall.

When it matters

Fat stranding is a sign, not a diagnosis. Common causes include appendicitis, diverticulitis, gallbladder inflammation, pancreatitis and infection. It is also seen after surgery or an injury, and with fluid build-up from heart, liver or kidney conditions. The radiologist links it to the organ at its center. What happens next depends on the cause and your symptoms, from a repeat scan to urgent care.

Questions to ask your doctor

Which organ is the fat stranding centered on?
Is the stranding mild, and does it fit with my symptoms?
Do I need blood tests or a follow-up scan to check it settles?

General information, not medical advice. What a finding means for you depends on your symptoms, your history and the images themselves, so talk your results through with a doctor.