title: Helical CT combined with contrast material administered only through the colon for imaging of suspected appendicitis.
abstract: OBJECTIVE
  Helical CT combined with contrast material administered by mouth and through the colon has been shown to be accurate for appendiceal imaging. This investigation was performed to determine if helical CT combined with contrast material administered only through the colon has comparable accuracy.
  
  
  METHODS
  One hundred patients prospectively underwent appendiceal CT imaging with thin-collimation, helical scanning limited to the lower abdomen and upper pelvis after contrast material was administered only through the colon. CT results were correlated with surgical and pathologic findings at appendectomy (56 patients), other surgery (three patients), or clinical follow-up at least 2 months after the CT scan (41 patients).
  
  
  RESULTS
  Fifty-three CT scans were interpreted as positive for appendicitis, including 52 true-positives (with surgical-pathologic correlation) and on false-positive (with clinical follow-up). Forty-seven CT scans were interpreted as negative for appendicitis, including 40 true-negatives with clinical follow-up, three true-negatives with appendectomy and pathologic correlation, three true-negatives with other surgery and pathologic correlation, and one false-negative with appendectomy and pathologic correlation. CT had a 98% sensitivity, 98% specificity, 98% positive predictive value, 98% negative predictive value, and 98% accuracy for diagnosing or excluding appendicitis. In 47 normal appendix cases at CT, the appendix was seen in 44 cases (94%), and an alternative diagnosis was identified in 29 cases (62%).
  
  
  CONCLUSIONS
  For diagnosing appendicitis, helical CT combined with contrast material administered only through the colon proved to be as accurate (98%) as helical CT combined with contrast material administered by mouth and through the colon. Helical CT with contrast material administered only through the colon also could be performed immediately and without any of the potential patient risks or discomforts of contrast material administered i.v. or by mouth.
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: A A
authors.initials: AA
authors.lastname: Mostafavi
authors.forename: J N
authors.initials: JN
authors.lastname: Lawrason
authors.forename: C J
authors.initials: CJ
authors.lastname: McCabe
mesh_terms: D000328:Adult; D001064:Appendicitis / Q000000981:diagnostic imaging*; D003106:Colon; D003287:Contrast Media / Q000008:administration & dosage*; D003974:Diatrizoate Meglumine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D003974:Diatrizoate Meglumine