title: Reflectance confocal microscopy for the diagnosis of eosinophilic esophagitis: a pilot study conducted on biopsy specimens.
abstract: BACKGROUND
  Diagnosis of eosinophilic esophagitis (EoE) currently requires endoscopic biopsy and histopathologic analysis of the biopsy specimens to count intraepithelial eosinophils. Reflectance confocal microscopy (RCM) is an endomicroscopy technology that is capable of obtaining high-resolution, optically sectioned images of esophageal mucosa without the administration of exogenous contrast.
  
  
  OBJECTIVE
  In this study, we investigated the capability of a high-speed form of RCM, termed spectrally encoded confocal microscopy (SECM), to count intraepithelial esophageal eosinophils and characterize other microscopic findings of EoE.
  
  
  METHODS
  A total of 43 biopsy samples from 35 pediatric patients and 8 biopsy samples from 8 adult patients undergoing EGD for EoE were imaged by SECM immediately after their removal and then processed for routine histopathology. Two SECM readers, trained on adult cases, prospectively counted intraepithelial eosinophils and detected the presence of abscess, degranulation, and basal cell hyperplasia on SECM images from the pediatric patients. A pathologist blinded to the SECM data analyzed the same from corresponding slides.
  
  
  METHODS
  The Gastrointestinal Unit, Massachusetts General Hospital.
  
  
  RESULTS
  Eosinophils by SECM demonstrated a higher reflectance than the surrounding cells and other inflammatory cells. There was good correlation between SECM and histology maximum eosinophil counts/high-power field (R = 0.76, P < .0001). Intra- and interobserver correlations for SECM counts were very good (R = 0.93 and R = 0.92, respectively; P < .0001). For the commonly used eosinophil count cutoff of 15 per high-power field, the sensitivity and specificity of SECM for EoE were 100%. The sensitivity and specificity for abscess, degranulation, and basal cell hyperplasia were 100% and 82%, 91% and 60%, and 94% and 80%, respectively. Intra- and interobserver agreements for these microscopic features of EoE were very good (κ = 0.9/0.9, 0.84/1.0, 0.91/0.81, respectively).
  
  
  CONCLUSIONS
  Ex vivo study.
  
  
  CONCLUSIONS
  This study demonstrates that RCM can be used to accurately count intraepithelial eosinophils and identify other microscopic abnormalities associated with EoE on freshly excised biopsy samples. These findings suggest that RCM may be developed into a tool for assessing eosinophilic infiltration in the esophagus in vivo.
authors.affiliation: Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
authors.forename: Hongki
authors.initials: H
authors.lastname: Yoo
authors.forename: DongKyun
authors.initials: D
authors.lastname: Kang
authors.forename: Aubrey J
authors.initials: AJ
authors.lastname: Katz
authors.forename: Gregory Y
authors.initials: GY
authors.lastname: Lauwers
authors.forename: Norman S
authors.initials: NS
authors.lastname: Nishioka
authors.forename: Yukako
authors.initials: Y
authors.lastname: Yagi
authors.forename: Pornthep
authors.initials: P
authors.lastname: Tanpowpong
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Namati
authors.forename: Brett E
authors.initials: BE
authors.lastname: Bouma
authors.forename: Guillermo J
authors.initials: GJ
authors.lastname: Tearney
mesh_terms: D000038:Abscess / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D001706:Biopsy; D002452:Cell Count; D015550:Cell Degranulation; D002648:Child; D002675:Child, Preschool; D016145:Endoscopy, Digestive System; D057765:Eosinophilic Esophagitis / Q000473:pathology*; D004804:Eosinophils / Q000473:pathology / Q000502:physiology*; D004947:Esophagus / Q000473:pathology*; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000473:pathology; D007223:Infant; D008297:Male; D018613:Microscopy, Confocal; D009092:Mucous Membrane / Q000473:pathology; D015588:Observer Variation; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D055815:Young Adult