Epiploic appendages are lobulated masses of fat attached to the serosal surface of the colon, and because of its fatty density, normally they cannot be distinguished from the mesenteric fat. Only with ascites or perhaps with gross free air would one be able to distinguish a normal epiploic appendage.

Hyperattenuating ring sign has been described in the literature as a rather characteristic finding of epiploic appendagitis. These epiploic appendages can torse at its attachment to the serosal surface of the colon and become infarcted and inflammated due to compromise of the vascular supply. In this case, the inflammed peritoneum surrounding the epiploic appendage becomes thickened and evident on CT, drawing an apparent ring around the epiploic appendage.

Primary epiploic appendagitis has been reported in 2.5-7.1% of patients who are suspected clinically of having diverticulitis, and approximately in 1.0% of patients suspected of having appendicitis.