title: Chromoendoscopy in magnetically guided capsule endoscopy.
abstract: BACKGROUND
  Diagnosis of intestinal metaplasia and dysplasia via conventional endoscopy is characterized by low interobserver agreement and poor correlation with histopathologic findings. Chromoendoscopy significantly enhances the visibility of mucosa irregularities, like metaplasia and dysplasia mucosa. Magnetically guided capsule endoscopy (MGCE) offers an alternative technology for upper GI examination. We expect the difficulties of diagnosis of neoplasm in conventional endoscopy to transfer to MGCE. Thus, we aim to chart a path for the application of chromoendoscopy on MGCE via an ex-vivo animal study.
  
  
  METHODS
  We propose a modified preparation protocol which adds a staining step to the existing MGCE preparation protocol. An optimal staining concentration is quantitatively determined for different stain types and pathologies. To that end 190 pig stomach tissue samples with and without lesion imitations were stained with different dye concentrations. Quantitative visual criteria are introduced to measure the quality of the staining with respect to mucosa and lesion visibility. Thusly determined optimal concentrations are tested in an ex-vivo pig stomach experiment under magnetic guidance of an endoscopic capsule with the modified protocol.
  
  
  RESULTS
  We found that the proposed protocol modification does not impact the visibility in the stomach or steerability of the endoscopy capsule. An average optimal staining concentration for the proposed protocol was found at 0.4% for Methylene blue and Indigo carmine. The lesion visibility is improved using the previously obtained optimal dye concentration.
  
  
  CONCLUSIONS
  We conclude that chromoendoscopy may be applied in MGCE and improves mucosa and lesion visibility. Systematic evaluation provides important information on appropriate staining concentration. However, further animal and human in-vivo studies are necessary.
authors.affiliation: Pattern Recognition Lab, University of Erlangen-Nuremberg, Martensstrasse 3, Erlangen Germany. philip.mewes@siemens.com
authors.forename: Philip W
authors.initials: PW
authors.lastname: Mewes
authors.forename: Stefan
authors.initials: S
authors.lastname: Foertsch
authors.forename: Aleksandar Lj
authors.initials: ALj
authors.lastname: Juloski
authors.forename: Elli
authors.initials: E
authors.lastname: Angelopoulou
authors.forename: Stefan K
authors.initials: SK
authors.lastname: Goelder
authors.forename: Dirk
authors.initials: D
authors.lastname: Guldi
authors.forename: Joachim
authors.initials: J
authors.lastname: Hornegger
authors.forename: Helmut
authors.initials: H
authors.lastname: Messmann
mesh_terms: D000818:Animals; D053704:Capsule Endoscopy / Q000379:methods*; D004396:Coloring Agents / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism; D060328:Magnetic Phenomena; D013194:Staining and Labeling; D013270:Stomach / Q000601:surgery; D013552:Swine
chemical_list: D004396:Coloring Agents