title: The most useful findings for diagnosing acute appendicitis on contrast-enhanced helical CT.
abstract: OBJECTIVE
  To evaluate the most useful findings to look for in diagnosing acute appendicitis on contrast-enhanced helical CT.
  
  
  METHODS
  Appendiceal helical CT scans with intravenous contrast administration (abdomen, 7-mm collimation; abdominopelvic junction, 5-mm collimation) of 71 patients with surgically proven acute appendicitis and 167 patients with alternative diagnoses were reviewed retrospectively. Three radiologists analyzed the following parameters: enlarged appendix (>6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), appendiceal intraluminal air, intramural air, extraluminal air, periappendiceal fat stranding, extraluminal fluid, phlegmon, abscess, lymphadenopathy, segmental terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. The features that best distinguished appendicitis from alternative diagnoses were selected with stepwise logistic regression analysis.
  
  
  RESULTS
  Nine CT findings distinguished acute appendicitis from alternative diagnoses (P < 0.05): enlarged appendix (R = 0.739), appendiceal wall thickening (R = 0.525), periappendiceal fat stranding (R = 0.414), appendiceal wall enhancement (R = 0.404), focal cecal apical thickening (R = 0.171), appendicolith(s) (R = 0.157), extraluminal air (R = 0.050), intramural air (R = 0.043), and phlegmon (R = 0.030). Enlarged appendix (sensitivity, 93%; specificity, 92%), appendiceal wall thickening (sensitivity, 66%; specificity, 96%), periappendiceal fat stranding (sensitivity, 87%; specificity, 74%), and appendiceal wall enhancement (sensitivity, 75%; specificity, 85%) showed the statistically most significant association with acute appendicitis.
  
  
  CONCLUSIONS
  On 5-mm-section contrast-enhanced helical CT examinations, enlarged appendix, appendiceal wall thickening, periappendiceal fat stranding, and appendiceal wall enhancement were the most useful findings for diagnosing acute appendicitis.
authors: Department of Radiology, Kangbuk Samsung Hospital, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. dichoi@smc.samsung.co.kr
authors: D
authors: D
authors: Choi
authors: H
authors: H
authors: Park
authors: Y R
authors: YR
authors: Lee
authors: S-H
authors: SH
authors: Kook
authors: S K
authors: SK
authors: Kim
authors: H J
authors: HJ
authors: Kwag
authors: E C
authors: EC
authors: Chung
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; D001466:Barium Sulfate; D002648:Child; D003287:Contrast Media; D003937:Diagnosis, Differential; D003974:Diatrizoate Meglumine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed
chemical_list: D003287:Contrast Media; D001466:Barium Sulfate; D003974:Diatrizoate Meglumine