Detection of Hyperechoic Inflammatory Fatty Tissue during Transabdominal Ultrasonography: Diagnostic Role in Acute Abdomen

Park, Seong Jin; Lee, Hae Kyung; Yi, Bum Ha; Kim, Hyun Cheol

Abstract

PURPOSE
To assess the incidence and diagnostic role of hyperechoic inflammatory fatty tissue (HIFT) in transabdominal ultrasonography (TAUS) for acute abdomen. MATERIALS AND METHODS: With TAUS, we examined 98 consecutive patients (68 women, 30 men; mean age, 32 years; age range, 4-84 years) having acute abdominal pain. We examined the abdomen and pelvis by TAUS to determine the cause of acute abdomen, to check for the presence of HIFT, and to investigate whether it was easier and earlier to find the main cause and HIFT presence. We also prospectively evaluated the shape, distribution, and diagnostic role of HIFT. Final diagnoses consisted of 47 cases of acute appendicitis, 14 of enterocolitis, 13 of PID, 7 of gynecological hemoperitoneum, 5 of colonic diverticulitis, 3 of ovarian torsion, 2 of colon perforation, 2 of only presence of non-specific HIFT, 1 of mesenteric lymphadenitis, and 4 of normal. RESULTS: HIFT were seen in 67 patients (68.4%), including 44/47(93.6%) of acute appendicitis, 2/14(14.3%) of enterocolitis, 11/13(84.6%) of PID, 0/7 of hemoperitoneum, 5/5 of colonic diverticulitis, 0/3 of ovarian torsion, 2/2 of colon perforation, and 1/1 mesenteric lymphadenitis. HIFT were detected earlier than the main cause in 17/44 of acute appendicitis, 6/11 of PID, and 4/5 of colonic diverticulitis. In acute appendicitis, the shape of HIFT appeared as fat thickening along the mesoappendix in 12/44, fat thickening along the mesoappendix and the opposite side in 13/44, fat encircled appendix in 6/44, fatty mass wrapping abscess in 10/44, and diffuse intraperitoneal fat thickening in 3/44. In PID, HIFT appeared as a single fatty mass in the pelvis and lower abdomen in 6/11, wrapping pelvic abscess in 2/11, and multiple fatty masses scattered in abdomen and pelvis in 3/11. In colonic diverticulitis, all 5 cases appeared as hyperechoic hemispheric mass covering the inflamed diverticulum. CONCLUSION: HIFT are a usual US finding in patients with acute abdomen, particularly on abdominal and pelvic inflammatory conditions, and they appear with characteristic shape and location in each disease. Therefore, earlier detection of HIFT using TAUS may be useful to make differential diagnosis and find complication in acute abdomen.