PURPOSE: To determine the changes in the computed tomographic (CT) appearance of primary epiploic appendagitis. MATERIALS AND METHODS: Clinical records and CT scans were reviewed in 10 patients who were initially suspected of having diverticulitis or appendicitis but were later determined to have primary epiploic appendagitis. The scans were obtained at the time of presentation and at follow-up 1-84 weeks later. RESULTS: Initial CT characteristics included mean size of 14 x 21 mm, oval (n = 9) or round (n = 1) shape, mean attenuation of -53 HU, visceral (n = 10) or parietal (n = 7) peritoneal thickening, periappendageal fat stranding (n = 10), adjacent bowel wall thickening (n = 4) or compression (n = 2), and central high-attenuating dot (n = 2). Follow-up CT characteristics included residual abnormality (n = 9); mean size of 10 x 15 mm; oval (n = 6), round (n = 2), or indistinct (n = 1) shape; mean attenuation of -68 HU; visceral (n = 5) or parietal (n = 3) peritoneal thickening; periappendageal fat stranding (n = 1); and central high-attenuating dot (n = 1). CT characteristics of the remnant lesion included smaller lesion with fat attenuation (n = 6), nugget with soft-tissue attenuation (n = 2), and nondescript fat stranding (n = 1). CONCLUSION: Awareness of the CT appearance of acute and healing primary epiploic appendagitis may help in the differential diagnosis of pericolonic abnormality.