Acute epiploic appendagitis most commonly manifests with acute lower quadrant pain. Its clinical features are similar to those of acute diverticulitis or, less commonly, acute appendicitis. The conditions that may mimic acute epiploic appendagitis at computed tomography (CT) include acute omental infarction, mesenteric panniculitis, fat-containing tumor, and primary and secondary acute inflammatory processes in the large bowel (eg, diverticulitis and appendicitis). Whereas the location of acute epiploic appendagitis is most commonly adjacent to the sigmoid colon, acute omental infarction is typically located in the right lower quadrant and often is mistaken for acute appendicitis. It is important to correctly diagnose acute epiploic appendagitis and acute omental infarction on CT images because these conditions may be mistaken for acute abdomen, and the mistake may lead to unnecessary surgery. The CT features of acute epiploic appendagitis include an oval lesion 1.5-3.5 cm in diameter, with attenuation similar to that of fat and with surrounding inflammatory changes, that abuts the anterior sigmoid colon wall. The CT features of acute omental infarction include a well-circumscribed triangular or oval heterogeneous fatty mass with a whorled pattern of concentric linear fat stranding between the anterior abdominal wall and the transverse or ascending colon. As CT increasingly is used for the evaluation of acute abdomen, radiologists are likely to see acute epiploic appendagitis and its mimics more often. Recognition of these conditions on CT images will allow appropriate management of acute abdominal pain and may help to prevent unnecessary surgery.

Routine appendiceal CT performed in patients who present with suspected appendicitis improves patient care and reduces the use of hospital resources.

Appendix CT examination can help diagnose or exclude appendicitis and establish an alternative diagnosis.

Fournier gangrene is a rapidly progressing necrotizing fasciitis involving the perineal, perianal, or genital regions and constitutes a true surgical emergency with a potentially high mortality rate. Although the diagnosis of Fournier gangrene is often made clinically, emergency computed tomography (CT) can lead to early diagnosis with accurate assessment of disease extent. CT not only helps evaluate the perineal structures that can become involved by Fournier gangrene, but also helps assess the retroperitoneum, to which the disease can spread. Findings at CT include asymmetric fascial thickening, subcutaneous emphysema, fluid collections, and abscess formation. Subcutaneous emphysema is the hallmark of Fournier gangrene but is not seen in all cases. Compared with radiography and ultrasonography, CT provides a higher specificity for the diagnosis of Fournier gangrene and superior evaluation of disease extent; however, diagnosis and evaluation can also be performed with these other modalities. The administration of broad-spectrum antibiotics and aggressive surgical débridement of the nonviable tissue are both essential for successful treatment. An awareness of the CT features of Fournier gangrene is imperative for prompt diagnosis and effective treatment planning.

Individual appendiceal CT signs of appendicitis vary in sensitivity, specificity, and thus diagnostic value. An enlarged appendix with periappendiceal fat stranding occurs in 93% of appendicitis CT cases. Less common but specific signs [cecal apical changes, appendolith(s) are usually present in the remaining appendicitis cases. Some signs seen with appendicitis (adenopathy, fat stranding, adjacent bowel wall thickening, fluid) can also be noted with alternative conditions, and in these cases normal appendix identification is the key to excluding appendicitis.