Gut signature sign

The gut signature sign is an ultrasound term used to describe the appearance of the gastrointestinal wall.

Radiographic features 

Ultrasound

The bowel wall has five layers, composed of alternating hyperechoic and hypoechoic appearances. Anatomically these layers are as follows (innermost to outermost) :

• superficial mucosa: echogenic
• muscularis mucosa: hypoechoic
• submucosa: echogenic (this is the thickest layer )
• muscularis propria: hypoechoic
• serosa: echogenic

The gut signature can be used to differentiate benign conditions, where gut signature is preserved and long segments of bowel are involved from malignant conditions where there is destruction of gut signature usually short segments of bowel .

It can also be used to identify the appendix, enteric duplication cysts, or differentiate bowel from intra-abdominal fluid collections.

Differential diagnosis

An intussusception may demonstrate prominent bowel walls on ultrasound with a differing configuration from the normal five layers:

• target sign (cross-sectional) and pseudokidney sign (longitudinal)