title: Fat halo sign in the bowel wall of patients with Crohn's disease.
abstract: OBJECTIVE
  To evaluate the prevalence and localization of the deposition of submucosal fat, the "fat halo sign" (FHS), using computed tomography (CT) in the bowel wall of patients with Crohn's Disease, and to assess its relation to the duration of the disease.
  
  
  METHODS
  The abdominal CT examinations of 100 consecutive patients were reviewed for the presence of the FHS in the bowel wall. A measurement of less than -10HU was regarded as indicative of fat. CT findings were correlated with the duration of the disease and statistically tested by simple regression analysis. The patients were divided into two groups: group A included 26 patients with a disease duration of less than 1 year and group B included 73 with a longer disease duration. In one patient disease duration was unknown. To test the relationship between disease duration and FHS the cumulative number of FHS positive and negative patients was plotted against disease duration.
  
  
  RESULTS
  The FHS was present in 17 of the 100 patients in 20 bowel segments, mainly in the ileum (10) and the ascending colon (8). The FHS was present in 3.8% in group A and in 21.9% in group B (p<0.0375).
  
  
  CONCLUSIONS
  The FHS was present in 17% of patients with CD. Its location was mainly in the terminal ileum and ascending colon, typical sites of the disease. Its prevalence was significantly duration dependent.
authors.affiliation: Department of Imaging, Chaim Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. michal.amitai@sheba.health.gov.il
authors.forename: M M
authors.initials: MM
authors.lastname: Amitai
authors.forename: T
authors.initials: T
authors.lastname: Arazi-Kleinman
authors.forename: B
authors.initials: B
authors.lastname: Avidan
authors.forename: S
authors.initials: S
authors.lastname: Apter
authors.forename: E
authors.initials: E
authors.lastname: Konen
authors.forename: A
authors.initials: A
authors.lastname: Biegon
authors.forename: M
authors.initials: M
authors.lastname: Hertz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003106:Colon / Q000000981:diagnostic imaging* / Q000473:pathology; D003424:Crohn Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014057:Tomography, X-Ray Computed