Fat stranding (summary)

This is a basic article for medical students and other non-radiologists

Fat stranding is a sign that is seen on CT. It describes the change in attenuation of fat around an inflamed structure and is a very helpful signpost for intra-abdominal pathology.

Reference article

This is a summary article; read more in our article on fat stranding on CT.

Summary

• pathophysiology
  • relatively high sensitivity for intra-abdominal pathology
    • many inflammatory processes will cause fat-stranding
  • non-specific
    • fat stranding just means that there is inflammation close by
  • common causes
    • appendicitis
    • pancreatitis
    • cholecystitis
    • diverticulitis
    • pyelonephritis
  • other causes
    • ischemia/infarction, e.g. omental infarction
    • vascular, e.g. aneurysm
• investigation
  • fat stranding is primarily seen on CT
  • inflammatory fat may be seen on US and MRI

Radiographic features

CT

The density of the affected fat changes. Usually fat is dark grey, but when there is edema in the fat, the density increases and it becomes progressively lighter and progressively closer to the density of muscle.​