Fat Halo Sign

An abdominal CT finding consisting of a thickened bowel wall
with three layers: an innermost layer corresponding to the mucosa, surrounded by a layer of fatty attenuation, which is in turn surrounded by the muscularis propria and serosa. Described as typical of inflammatory bowel disease—Crohn’s disease and ulcerative colitis—it has also been reported as an acute finding in graft-versus-host disease and cytoreductive surgery

References in periodicals archive ?

Intramural stratification with deposition of fat in the submucosal layer of the bowel wall, visualised on computed tomographic (CT) scans of the abdomen, is known as the fat halo sign. (1) Owing to infiltration of the submucosa by fat, the inner layer mucosa are separated from the outer layer of muscularis propria/serosa (both being of soft tissue density) by a layer of fat (of low attenuation) measuring between-18 to-64 Hounsfield units.

Historically, the fat halo sign has been associated with patients suffering from chronic inflammatory bowel disease.

conducted a study in 2003 evaluating the presence and frequency of the fat halo sign in patients undergoing abdominal CT for clinical indications unrelated to the gastrointestinal tract.

Pitfalls associated with interpretation of the fat halo sign specifically involve intestinal distension.

In conclusion: the presence of the fat halo sign may in the absence of clinical and radiological features of inflammatory bowel disease represent a normal finding that may also be related to obesity.

The fat halo sign

The fat halo sign is now known to occur only in patients whose mass exceeds 120 kg.