title: A comparison of magnifying and nonmagnifying colonoscopy for diagnosis of colorectal polyps: A prospective study.
abstract: BACKGROUND
  Discrimination between neoplastic and non-neoplastic colorectal polyps is essential for determining appropriate treatment. The mucosal crypt pattern of polyps can be observed with a nonmagnifying colonoscope; however, mucosal crypt patterns are better seen by magnifying colonoscopy, which can also be a noninvasive means for predicting histopathology. This study prospectively compared the ability to distinguish between neoplastic and non-neoplastic lesions by magnifying and nonmagnifying colonoscopy.
  
  
  METHODS
  Six hundred sixty patients were randomly assigned to undergo magnifying or nonmagnifying colonoscopy (2 groups each of 330 patients). The mucosal crypt pattern of colorectal lesions was classified into types I through V after spraying with 0.2% Indigo carmine dye. The histopathology of all lesions was confirmed by evaluation of endoscopic resection specimens or biopsy specimens. Only lesions 10 mm or less in diameter were included in the study.
  
  
  RESULTS
  The accuracy of magnifying colonoscopy in distinguishing neoplastic from non-neoplastic lesions (92%, 372/405) was significantly higher than for nonmagnifying colonoscopy (68%, 278/407). Insertion of magnifying and nonmagnifying colonoscopes to the cecum was successful in, respectively, 321 patients (97%) and 317 patients (96%), with no significant differences in the average time to reach the cecum or average total procedure time. No serious complication was observed during or immediately after the examinations.
  
  
  CONCLUSIONS
  Observation of mucosal crypt pattern with magnifying colonoscopy is superior to nonmagnifying colonoscopy for distinguishing between neoplastic and non-neoplastic colorectal lesions.
authors.affiliation: Second Department of Internal Medicine, Division of Hospital Pathology, Showa University School of Medicine, Tokyo, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Konishi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kaneko
authors.forename: Toshinori
authors.initials: T
authors.lastname: Kurahashi
authors.forename: Taikan
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Miki
authors.initials: M
authors.lastname: Kushima
authors.forename: Akira
authors.initials: A
authors.lastname: Kanda
authors.forename: Hisao
authors.initials: H
authors.lastname: Tajiri
authors.forename: Keiji
authors.initials: K
authors.lastname: Mitamura
mesh_terms: D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy / Q000379:methods*; D004396:Coloring Agents; D003937:Diagnosis, Differential; D006801:Humans; D007203:Indigo Carmine; D007413:Intestinal Mucosa / Q000473:pathology*; D011230:Precancerous Conditions / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D004396:Coloring Agents; D007203:Indigo Carmine