Table 1.

Signs assessed

Sign assessed	Notes
Bowel
Mural thickening	If distended: >3 mm considered abnormal
	If collapsed >10 mm considered abnormal
Mural thinning
Pneumatosis
Bowel wall oedema	Wall thickening with fluid attenuation
Small bowel faeces sign	The presence of particulate (colon-like) faeculent matter mingled with gas bubbles in the lumen of dilated loops of the small intestine
Bowel obstruction
Bowel-loop dilatation	Small bowel: >2.5 cm considered abnormal
	Large bowel: >6 cm considered abnormal (Caecum: >8 cm)
Vascular
Differential mural enhancement	Considered pathological when absent, inhomogeneous, or marked and persistent
Venous thrombus
Arterial occlusion	SMA/IMA/coeliac
Arterial calcification	SMA/IMA/coeliac
Other
Mesenteric stranding
Ascites	Not quantified
Solid organ infarction
Free intraperitoneal air	Allowing for expected post-operative gas
Portal venous gas
Mesenteric venous gas	Including presence of gas within the mesenteric venules
IABP position	See text

IABP, intra-arterial balloon pump; IMA, inferior mesenteric artery; SMA, superior mesenteric artery.