title: Halo sign: useful CT sign for differentiating benign from malignant colonic disease.
abstract: OBJECTIVE
  To evaluate the halo sign for accurately distinguishing benign from malignant colonic wall thickening.
  
  
  METHODS
  Computed tomography (CT) examinations of 92 patients (70 men; 22 women; mean age 57 years) with pathologically proven colonic wall thickening (51 benign and 41 malignant) were retrospectively reviewed in a blinded fashion. The affected segment was assessed for presence of the halo sign, degree and uniformity of thickness and density of the intramural stratum.
  
  
  RESULTS
  The halo sign was present in 74.5% (38/51) patients with benign and 7.3% (3/41) patients with malignant bowel disease. The presence of the halo sign was 75.4% sensitive and 92.5% specific for benign bowel wall thickening. All 38 benign halos showed uniform, continuous stratification; only one of three malignant halos met the strict criteria for benign halo.
  
  
  CONCLUSIONS
  The halo sign is a moderately sensitive and highly specific sign for distinguishing benign from malignant bowel wall thickening. However, it is not pathognomonic for benign disease. Detailed analysis of halo characteristics is necessary to improve the usefulness of this finding.
authors.affiliation: Division of Abdominal Imaging and Intervention, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA. mharisinghani@partners.org
authors.forename: M G
authors.initials: MG
authors.lastname: Harisinghani
authors.forename: J
authors.initials: J
authors.lastname: Wittenberg
authors.forename: M A
authors.initials: MA
authors.lastname: Blake
authors.forename: S
authors.initials: S
authors.lastname: Chen
authors.forename: K
authors.initials: K
authors.lastname: Jhaveri
authors.forename: P R
authors.initials: PR
authors.lastname: Mueller
mesh_terms: D003108:Colonic Diseases / Q000000981:diagnostic imaging*; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*