title: Helical CT technique for the diagnosis of appendicitis: prospective evaluation of a focused appendix CT examination.
abstract: OBJECTIVE
  To evaluate a focused, helical computed tomographic (CT) technique for imaging the appendix in patients suspected of having appendicitis.
  
  
  METHODS
  One hundred patients prospectively underwent appendix CT examination, with use of oral and colon contrast media and contiguous, thin-collimation, helical CT imaging of the right lower quadrant. Results were correlated with the results of surgery and pathologic examination from 61 patients or from clinical follow-up in 39 patients.
  
  
  RESULTS
  CT scans were positive for appendicitis in 59 patients: true-positive in 56 patients on the basis of surgery and pathologic examination, and false-positive in two patients on the basis of clinical follow-up; in the case of the other positive scan, the clinical outcome was indeterminate. CT scans were negative for appendicitis in 41 patients: true-negative in five patients on the basis of surgery and pathologic examination, and true-negative in 36 patients on the basis of clinical follow-up. CT had a sensitivity of 100%, a specificity of 95%, a positive predictive value of 97%, a negative predictive value of 100%, and an accuracy of 98%. The normal appendix was always identified. CT helped establish alternative diagnoses in 33 of the 41 patients (80%) in whom the results of CT were negative for appendicitis.
  
  
  CONCLUSIONS
  Appendix CT examination can help diagnose or exclude appendicitis and establish an alternative diagnosis.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Rao
authors.forename: J T
authors.initials: JT
authors.lastname: Rhea
authors.forename: R A
authors.initials: RA
authors.lastname: Novelline
authors.forename: C J
authors.initials: CJ
authors.lastname: McCabe
authors.forename: J N
authors.initials: JN
authors.lastname: Lawrason
authors.forename: D L
authors.initials: DL
authors.lastname: Berger
authors.forename: R
authors.initials: R
authors.lastname: Sacknoff
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000000981:diagnostic imaging*; D001065:Appendix / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*