title: Optical coherence tomography: advanced technology for the endoscopic imaging of Barrett's esophagus.
abstract: OBJECTIVE
  Endoscopic optical coherence tomography (OCT) is an emerging medical technology capable of generating high-resolution cross-sectional imaging of tissue microstructure in situ and in real time. We assess the use and feasibility of OCT for real-time screening and diagnosis of Barrett's esophagus, and also review state-of-the-art OCT technology for endoscopic imaging.
  
  
  METHODS
  OCT imaging was performed as an adjunct to endoscopic imaging of the human esophagus. Real-time OCT (13-microm resolution) was used to perform image-guided evaluation of normal esophagus and Barrett's esophagus. Beam delivery was accomplished with a 1-mm diameter OCT catheter-probe that can be introduced into the accessory channel of a standard endoscope. Different catheter-probe imaging designs which performed linear and radial scanning were assessed. Novel ultrahigh-resolution (1.1-microm resolution) and spectroscopic OCT techniques were used to image in vitro specimens of Barrett's esophagus.
  
  
  RESULTS
  Endoscopic OCT images revealed distinct layers of normal human esophagus extending from the epithelium to the muscularis propria. In contrast, the presence of gland- and crypt-like morphologies and the absence of layered structures were observed in Barrett's esophagus. All OCT images showed strong correlations with architectural morphology in histological findings. Ultrahigh-resolution OCT techniques achieved 1.1-microm image resolution in in vitro specimens and showed enhanced resolution of architectural features. Spectroscopic OCT identified localized regions of wavelength-dependent optical scattering, enhancing the differentiation of Barrett's esophagus.
  
  
  CONCLUSIONS
  OCT technology with compact fiberoptic imaging probes can be used as an adjunct to endoscopy for real-time image-guided evaluation of Barrett's esophagus. Linear and radial scan patterns have different advantages and limitations depending upon the application. Ultrahigh-resolution and spectroscopic OCT techniques improve structural tissue recognition and suggest future potential for resolution and contrast enhancements in clinical studies. A new balloon catheter-probe delivery device is proposed for systematic imaging and screening of the esophagus.
authors.affiliation: Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, USA.
authors.forename: X D
authors.initials: XD
authors.lastname: Li
authors.forename: S A
authors.initials: SA
authors.lastname: Boppart
authors.forename: J
authors.initials: J
authors.lastname: Van Dam
authors.forename: H
authors.initials: H
authors.lastname: Mashimo
authors.forename: M
authors.initials: M
authors.lastname: Mutinga
authors.forename: W
authors.initials: W
authors.lastname: Drexler
authors.forename: M
authors.initials: M
authors.lastname: Klein
authors.forename: C
authors.initials: C
authors.lastname: Pitris
authors.forename: M L
authors.initials: ML
authors.lastname: Krinsky
authors.forename: M E
authors.initials: ME
authors.lastname: Brezinski
authors.forename: J G
authors.initials: JG
authors.lastname: Fujimoto
mesh_terms: D001471:Barrett Esophagus / Q000473:pathology*; D004867:Equipment Design; D020701:Esophagoscopes; D004945:Esophagoscopy / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D014054:Tomography