title: Computed tomography and ultrasonography do not improve and may delay the diagnosis and treatment of acute appendicitis.
abstract: OBJECTIVE
  Computed tomography (CT) and ultrasonography (US) do not improve the overall diagnostic accuracy for acute appendicitis.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  University tertiary care center.
  
  
  METHODS
  Seven hundred sixty-six consecutive patients undergoing appendectomy for suspected appendicitis from January 1, 1995, to December 31, 1999.
  
  
  METHODS
  Epidemiology of acute appendicitis and the roles of clinical assessment, CT, US, and laparoscopy.
  
  
  RESULTS
  The negative appendectomy rate was 15.7%, and the incidence of perforated appendicitis was 14.6%. A history of migratory pain had the highest positive predictive value (91%), followed by leukocytosis greater than 12 x 10(9)/L (90.1%), CT (83.8%), and US (81.3%). The false-negative rates were 60% for CT and 76.1% for US. Emergency department evaluation took a mean +/- SD of 5.2 +/- 5.4 hours and was prolonged by US or CT (6.4 +/- 7.4 h and 7.8 +/- 10.8 h, respectively). The duration of emergency department evaluation did not affect the perforation rate, but patients with postoperative complications had longer evaluations (mean +/- SD, 8.0 +/- 12.7 h) than did those without (4.8 +/- 3.3 h) (P =.04). Morbidity was 9.1%, 6.4% for nonperforated cases and 19.8% for perforated cases. Seventy-six patients had laparoscopic appendectomy, with a negative appendectomy rate of 42.1%, compared with 15.4% for open appendectomy (P<.001). Laparoscopy, however, had minimal morbidity (1.3%) and correctly identified the abnormality in 91.6% of patients who had a normal-appearing appendix.
  
  
  CONCLUSIONS
  Migratory pain, physical examination, and initial leukocytosis remain reliable and accurate in diagnosing acute appendicitis. Neither CT nor US improves the diagnostic accuracy or the negative appendectomy rate; in fact, they may delay surgical consultation and appendectomy. In atypical cases, one should consider the selective use of diagnostic laparoscopy instead.
authors.affiliation: Department of Surgery, University of California Davis Medical Center, 2221 Stockton Blvd, 3rd Floor, Sacramento, CA 95817, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Lee
authors.forename: A J
authors.initials: AJ
authors.lastname: Walsh
authors.forename: H S
authors.initials: HS
authors.lastname: Ho
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001062:Appendectomy / Q000379:methods; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000601:surgery; D002648:Child; D005260:Female; D006801:Humans; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography