comb sign

Massive
porto-mesenteric venous thrombosis in Crohn"s disease. Distal ileum with thickened wall and mucosal hyperenhancement (arrowheads), hypertrophied mesenteric fat with vascular engorgement ("comb sign", *) consistent with active Crohn"s disease, mild upstream bowel dilatation (*). Note patent portal (thick arrow) and mesenteric (arrows) veins.
www.eurorad.org • CC by-nc-sa-4.0
Massive
porto-mesenteric venous thrombosis in Crohn"s disease. Distal ileum with thickened wall and mucosal hyperenhancement (arrowheads), hypertrophied mesenteric fat with vascular engorgement ("comb sign", *) consistent with active Crohn"s disease.
www.eurorad.org • CC by-nc-sa-4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

The comb sign refers to the hypervascular appearance of the mesentery in active Crohn disease. Fibrofatty proliferation and perivascular inflammatory infiltration outline the distended intestinal arcades. This forms linear densities on the mesenteric side of the affected segments of small bowel, which give the appearance of the teeth of a comb.

The sign may be seen on both CT and MRI. It is not pathognomonic of Crohn disease; however, in a known case of Crohn disease would suggest that the disease was extensive, advanced and active. However, the comb sign can be seen in other acute inflammatory conditions of bowel and lupus mesenteric vasculitis.

The comb sign may be used to differentiate active inflammatory conditions from lymphoma and metastases, which tend to be hypovascular.

See also

Siehe auch:
Assoziationen und Differentialdiagnosen zu comb sign:
superior
mesenteric artery (SMA)
Wikipedia • Public domain
Comb sign of
Crohn disease
www.eurorad.org • CC by-nc-sa-4.0