title: Dual optical modality endoscopic imaging of cancer development in the mouse colon.
abstract: OBJECTIVE
  We utilize a miniature, dual-modality endoscope that combines fluorescence-based surface magnifying chromoendoscopy (SMC) and optical coherence tomography (OCT) to follow the anatomical changes that occur during adenoma development in the mouse colon.
  
  
  METHODS
  Twenty-five mice were treated with the carcinogen azoxymethane (AOM) to induce tumor development in the distal colon, or were treated with saline as control, and were imaged over six months. OCT detects adenoma number with high sensitivity and specificity and can measure lesion size. In methylene blue-lavaged colons, SMC detects changes in the colonic crypts. SMC images of control mouse colons exhibit reticulated patterns of crypts of equal size, forming either a dot or honeycomb pattern.
  
  
  RESULTS
  Images of AOM-treated colons show mild crypt irregularities even in grossly normal tissue. Images of small to medium adenoma exhibit larger crypts, more intense signal, and irregular spacing whereas those of large adenoma have heterogeneous, intense signal and loss of crypt structure.
  
  
  CONCLUSIONS
  The combination of OCT and SMC permits the detection of neoplastic events from the earliest stages of crypt irregularities before gross tissue changes are noted, through to measuring the growth of protruding adenoma.
authors.affiliation: The University of Arizona, Department of Biomedical Engineering, 1657 E. Helen Street, 210240, Tucson, Arizona, 85721.
authors.forename: Molly R
authors.initials: MR
authors.lastname: Keenan
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Leung
authors.forename: Photini S
authors.initials: PS
authors.lastname: Rice
authors.forename: R Andrew
authors.initials: RA
authors.lastname: Wall
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Barton
mesh_terms: D000236:Adenoma / Q000139:chemically induced / Q000175:diagnosis*; D000818:Animals; D001397:Azoxymethane; D002273:Carcinogens; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000175:diagnosis*; D003113:Colonoscopy / Q000379:methods*; D004396:Coloring Agents; D005260:Female; D008751:Methylene Blue; D051379:Mice; D015588:Observer Variation; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D002273:Carcinogens; D004396:Coloring Agents; D001397:Azoxymethane; D008751:Methylene Blue
keywords: Chromoendoscopy; magnifying endoscopy; methylene blue; optical coherence tomography; pit pattern