title: Confocal laser endomicroscopy for the differential diagnosis of ulcerative colitis and Crohn's disease: a pilot study.
abstract: OBJECTIVE
  The differential diagnosis of ulcerative colitis from Crohn's disease is of pivotal importance for the management of inflammatory bowel diseases, as both entities involve specific therapeutic management strategies. Confocal laser endomicroscopy (CLE) allows on-demand, in vivo characterization of architectural and cellular details during endoscopy. The aim of this study was to assess the efficacy of CLE to differentiate between ulcerative colitis and Crohn's disease.
  
  
  METHODS
  This was a prospective study involving consecutive patients with a well-established diagnosis of ulcerative colitis or Crohn's disease who underwent colonoscopy with fluorescein-aided confocal imaging.
  
  
  RESULTS
  Overall, 79 patients were included (40 Crohn's disease, 39 ulcerative colitis). CLE findings in patients with Crohn's disease, showed significantly more discontinuous inflammation (87.5 % vs. 5.1 %), focal cryptitis (75.0 % vs. 12.8 %), and discontinuous crypt architectural abnormality (87.5 % vs. 10.3 %) than in ulcerative colitis (P < 0.0001). Conversely, ulcerative colitis was associated with severe, widespread crypt distortion (87.2 % vs. 17.5 % in Crohn's disease), decreased crypt density (79.5 % vs. 22.5 %), and frankly irregular surface (89.7 % vs. 17.5 %; P < 0.0001 for all comparisons). Statistically significant differences were not seen for heavy, diffuse lamina propria cell increase or mucin preservation. No granulomas were visible. Based on these findings, a CLE scoring system was developed that revealed excellent accuracy (93.7 %) when compared with the historical clinical diagnosis and the histopathological gold standard.
  
  
  CONCLUSIONS
  CLE could visualize several disease-specific microscopic features, which are conventionally used in standard histopathology to differentiate between ulcerative colitis and Crohn's disease. However, because of the limited penetration depth of CLE, submucosal details or granulomas were not visible. The new scoring system may allow in vivo diagnosis of ulcerative colitis or Crohn's disease. Trial registered at ClinicalTrials.gov: NCT 02238665.
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Gian Eugenio
authors.initials: GE
authors.lastname: Tontini
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Jonas
authors.initials: J
authors.lastname: Mudter
authors.affiliation: Institute of Pathology, Klinikum Bayreuth, Bayreuth, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Vieth
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Raja
authors.initials: R
authors.lastname: Atreya
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Günther
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Yurdagül
authors.initials: Y
authors.lastname: Zopf
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Dane
authors.initials: D
authors.lastname: Wildner
authors.affiliation: St. Marienkrankenhaus Katharina-Kasper, Frankfurt am Main, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kiesslich
authors.affiliation: Gastroenterology and Digestive Endoscopy Unit, IRCCS Policlinico San Donato, San Donato Milanese, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Vecchi
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Markus F
authors.initials: MF
authors.lastname: Neurath
authors.affiliation: Department of Medicine, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Neumann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003093:Colitis, Ulcerative / Q000473:pathology*; D003113:Colonoscopy; D003424:Crohn Disease / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D019793:Fluorescein; D005456:Fluorescent Dyes; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology*; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D005456:Fluorescent Dyes; D019793:Fluorescein