title: Ultrasonography in acute appendicitis. Body mass index as selection factor for US examination.
abstract: OBJECTIVE
  Acute appendicitis is often difficult to diagnose and a negative laparotomy rate of about 25% is common. At Danderyd Hospital we started routine US in these patients, the aim being to estimate the sensitivity and the specificity for US when compared with the body mass index (BMI) of the patient.
  
  
  METHODS
  All patient records were examined: During a period of 6 months 142 patients over 14 years of age were investigated with US. Their height and weight were noted and the BMI was calculated.
  
  
  RESULTS
  The sensitivity for US examination was 0.76 in patients with a BMI < 25 but only 0.37 in patients with BMI > or = 25. This difference was statistically significant.
  
  
  CONCLUSIONS
  US is a good method for examination of patients with BMI less than 25 but not in patients with BMI over 25.
authors.affiliation: Department of Radiology, Karolinska Institutet at Danderyd Hospital, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Josephson
authors.forename: J
authors.initials: J
authors.lastname: Styrud
authors.forename: S
authors.initials: S
authors.lastname: Eriksson
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000601:surgery; D001065:Appendix / Q000000981:diagnostic imaging; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002137:Calculi / Q000000981:diagnostic imaging; D016009:Chi-Square Distribution; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007813:Laparotomy; D008297:Male; D018579:Patient Selection; D012680:Sensitivity and Specificity; D014463:Ultrasonography