Primary epiploic appendagitis (PEA) and segmental omental infarction and their associated CT and MRI features
PEA and segmental omental infarction are self-limited conditions that often manifest with focal severe acute abdominal pain and tenderness and are treated with conservative therapy (e.g., analgesics). PEA is related to torsion, inflammation, and ischemia of an epiploic appendage, and segmental omental infarction is related to spontaneous infarction of a portion of the omentum.
CT and MRI findings of PEA include a small (1 to 5 cm) round or oval pedunculated fat attenuation/signal intensity structure with a soft tissue enhancing rim located adjacent to the serosal surface of the large bowel (in the expected location of an epiploic appendage), commonly with a high attenuation/low signal intensity central dot or line from thrombosis of a central vein or fibrosis. Associated inflammatory fat stranding and reactive bowel wall or peritoneal thickening may also be seen. PEA occurs most commonly adjacent to the sigmoid colon.
CT and MRI findings of segmental omental infarction include a large (5 to 10 cm) well-circumscribed focus of fat attenuation/signal intensity with associated inflammatory fat stranding. Typically, the infarction is located in the right anterolateral aspect of the abdomen between the colon and parietal peritoneum at or above the umbilical level (in the expected location of the greater omentum).
