title: Accuracy and radiation dose reduction of a limited abdominopelvic CT in the diagnosis of acute appendicitis.
abstract: OBJECTIVE
  To determine the accuracy and radiation dose reduction of a limited abdominopelvic CT from the bottom of T10 to the top of the pubic symphysis in patients with suspected acute appendicitis.
  
  
  METHODS
  We performed a HIPAA compliant and IRB-approved retrospective study of adult patients who underwent CT abdomen/pelvis for suspected appendicitis. The Z-axis length and whole body effective doses of the original full scan and theoretical limited scan from the bottom of T10 to the top of the pubic symphysis were recorded. Images were reviewed to determine if the appendix or entire cecum would be visualized and if any cases of appendicitis or alternative diagnoses would be missed with the limited scan.
  
  
  RESULTS
  235 patients (89 male, mean age 44.6 years) were included. The limited scan resulted in a mean Z-axis length reduction of 5.1 cm superiorly, 6.1 cm inferiorly, and a total reduction of 11.2 cm (24%). The mean whole body effective dose was 11.8 and 9.1 mSv for the original and limited scans, respectively (23% reduction). The entire appendix or cecum was visualized in all cases. Appendicitis was present in 24 cases and an alternative diagnosis was made in 75. No cases of appendicitis or alternative diagnoses were missed using the limited scan.
  
  
  CONCLUSIONS
  A limited range CT from the bottom of T10 to the top of the pubic symphysis is as accurate as full abdominopelvic CT in evaluating patients with suspected acute appendicitis and results in approximately 23% dose reduction.
authors.affiliation: Department of Radiology, University of California, Davis Medical Center, 4860 Y Street, Suite 3100, Sacramento, CA, 95817, USA, Michael.corwin@ucdmc.ucdavis.edu.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Corwin
authors.forename: Melanie
authors.initials: M
authors.lastname: Chang
authors.forename: Ghaneh
authors.initials: G
authors.lastname: Fananapazir
authors.forename: Anthony
authors.initials: A
authors.lastname: Seibert
authors.forename: Ramit
authors.initials: R
authors.lastname: Lamba
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000000981:diagnostic imaging*; D001065:Appendix / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult