title: Alvarado score: can it reduce unnecessary CT scans for evaluation of acute appendicitis?
abstract: OBJECTIVE
  The objective of the study is to assess the utility of Alvarado score in the diagnosis of acute appendicitis and the utility of computed tomographic (CT) scan for evaluation of acute appendicitis when stratified by Alvarado scores.
  
  
  METHODS
  Retrospective cohort study comprised adult patients who underwent abdominal CT for suspected acute appendicitis between January 2006 and December 2009. Two abdominal radiologists independently reviewed the CT scans; any discrepancies were resolved by a consensus review. Alvarado scores were calculated and categorized as low (0-3), equivocal (4-6), or high (7-10) probability for appendicitis. The diagnostic utility of CT scans and Alvarado score for acute appendicitis were compared with the criterion standard of combined medical chart review and pathology findings.
  
  
  RESULTS
  In a cohort of 158 subjects, 73 (46.2%) had clinical diagnoses of acute appendicitis. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CT scan in the diagnosis of acute appendicitis were 97.5%, 98.6%, 96.5%, 96.0%, and 98.8%, respectively. The mean Alvarado score for subjects with complicated appendicitis was significantly higher (7.95) than subjects with uncomplicated appendicitis (6.67) and those with other diagnoses (5.95). Acute appendicitis was confirmed in 2 (13.3%) of 15 subjects with low probability Alvarado scores, 16 (30.8%) of 52 subjects with equivocal scores, and 55 (60.4%) of 91 subjects with high probability scores.
  
  
  CONCLUSIONS
  The CT scan had high diagnostic utility for acute appendicitis. The Alvarado score was not a reliable independent predictive tool for acute appendicitis and could not replace CT scan.
authors.affiliation: Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand.
authors.forename: Piyaporn
authors.initials: P
authors.lastname: Apisarnthanarak
authors.affiliation: Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand.
authors.forename: Voraparee
authors.initials: V
authors.lastname: Suvannarerg
authors.affiliation: Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand.
authors.forename: Poompis
authors.initials: P
authors.lastname: Pattaranutaporn
authors.affiliation: Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand.
authors.forename: Aphinya
authors.initials: A
authors.lastname: Charoensak
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Raman
authors.affiliation: Division of Infectious Diseases, Thammasart University Hospital, Pratumthani, Thailand. Electronic address: anapisarn@yahoo.com.
authors.forename: Anucha
authors.initials: A
authors.lastname: Apisarnthanarak
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001064:Appendicitis / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D055815:Young Adult