A Confocal Endoscope for Cellular Imaging

ABSTRACT Since its inception, endoscopy has aimed to establish an immediate diagnosis that is virtually consistent with a histologic diagnosis. In the past decade, confocal laser scanning microscopy has been brought into endoscopy, thus enabling in vivo microscopic tissue visualization with a magnification and resolution comparable to that obtained with the ex vivo microscopy of histological specimens. The major challenge in the development of instrumentation lies in the miniaturization of a fiber-optic probe for microscopic imaging with micron-scale resolution. Here, we present the design and construction of a confocal endoscope based on a fiber bundle with 1.4-μm lateral resolution and 8-frames per second (fps) imaging speed. The fiber-optic probe has a diameter of 2.6 mm that is compatible with the biopsy channel of a conventional endoscope. The prototype of a confocal endoscope has been used to observe epithelial cells of the gastrointestinal tracts of mice and will be further demonstrated in clinical trials. In addition, the confocal endoscope can be used for translational studies of epithelial function in order to monitor how molecules work and how cells interact in their natural environment.

[1]  B Messerschmidt,et al.  Endoscope-compatible confocal microscope using a gradient index-lens system , 2001 .

[2]  C. Sheppard,et al.  Image formation in a fiber-optical confocal scanning microscope , 1991 .

[3]  R. Kiesslich,et al.  Technology Insight: confocal laser endoscopy for in vivo diagnosis of colorectal cancer , 2007, Nature Clinical Practice Oncology.

[4]  Markus F Neurath,et al.  Molecular imaging of VEGF in gastrointestinal cancer in vivo using confocal laser endomicroscopy , 2010, Gut.

[5]  Barry Campbell,et al.  Confocal laser endomicroscopy is a new imaging modality for recognition of intramucosal bacteria in inflammatory bowel disease in vivo , 2010, Gut.

[6]  Joel N. Bixler,et al.  Confocal Endomicroscopy: Instrumentation and Medical Applications , 2012, Annals of Biomedical Engineering.

[7]  Robert T Kester,et al.  Low cost, high performance, self-aligning miniature optical systems. , 2009, Applied optics.

[8]  W. Gong,et al.  The Accuracy of Confocal Laser Endomicroscopy, Narrow Band Imaging, and Chromoendoscopy for the Detection of Atrophic Gastritis , 2015, Journal of clinical gastroenterology.

[9]  David S. Greenberg,et al.  Visually evoked activity in cortical cells imaged in freely moving animals , 2009, Proceedings of the National Academy of Sciences.

[10]  Alexander Meining,et al.  Direct visualization of indeterminate pancreaticobiliary strictures with probe-based confocal laser endomicroscopy: a multicenter experience. , 2011, Gastrointestinal endoscopy.

[11]  A. Zvyagin.  Multiphoton endoscopy , 2007 .

[12]  Olav Solgaard,et al.  In vivo brain imaging using a portable 2.9 g two-photon microscope based on a microelectromechanical systems scanning mirror. , 2009, Optics letters.

[13]  L. E. Curtiss,et al.  Preliminary report on a long fiberscope for examination of stomach and duodenum. , 1957, Medical bulletin.

[14]  Michael Vieth,et al.  In vivo molecular imaging of colorectal cancer with confocal endomicroscopy by targeting epidermal growth factor receptor. , 2010, Gastroenterology.

[15]  E. Cocker,et al.  Fiber-optic fluorescence imaging , 2005, Nature Methods.

[16]  T. Stamey,et al.  Prostate-Specific Antigen as a Serum Marker for Adenocarcinoma of the Prostate , 1987 .

[17]  Moon Gi Kang,et al.  Super-resolution image reconstruction: a technical overview , 2003, IEEE Signal Process. Mag..

[18]  M. Descour,et al.  Design of a high-numerical-aperture miniature microscope objective for an endoscopic fiber confocal reflectance microscope. , 2002, Applied optics.

[19]  A. Polglase,et al.  Confocal laser endoscopy for diagnosing intraepithelial neoplasias and colorectal cancer in vivo. , 2004, Gastroenterology.

[20]  P. Cochat,et al.  Et al , 2008, Archives de pediatrie : organe officiel de la Societe francaise de pediatrie.

[21]  O. Pech,et al.  Comparison of computed virtual chromoendoscopy and conventional chromoendoscopy with acetic acid for detection of neoplasia in Barrett’s esophagus , 2007, Endoscopy.

[22]  A. Mehta,et al.  Multiphoton endoscopy: optical design and application to in vivo imaging of mammalian hippocampal neurons , 2003, Conference on Lasers and Electro-Optics, 2003. CLEO '03..

[23]  M. Wallace,et al.  New classification for probe-based confocal laser endomicroscopy in the colon , 2011, Endoscopy.

[24]  Martin Goetz,et al.  Microscopic imaging in endoscopy: endomicroscopy and endocytoscopy , 2014, Nature Reviews Gastroenterology &Hepatology.

[25]  A. Gmitro,et al.  Confocal microscopy through a fiber-optic imaging bundle. , 1993, Optics letters.

[26]  Z. Li,et al.  Note: a resonant fiber-optic piezoelectric scanner achieves a raster pattern by combining two distinct resonances. , 2012, The Review of scientific instruments.

[27]  Matthew D. Chidley,et al.  Design, assembly, and optical bench testing of a high-numerical-aperture miniature injection-molded objective for fiber-optic confocal reflectance microscopy. , 2006, Applied optics.

[28]  T Wilson,et al.  Confocal scanning optical microscope using single-mode fiber for signal detection. , 1991, Applied optics.

[29]  Angelique Kano,et al.  Design and demonstration of a miniature catheter for a confocal microendoscope. , 2004, Applied optics.

[30]  Martin Goetz,et al.  Confocal laser endomicroscopy in gastrointestinal diseases , 2011, Journal of biophotonics.

[31]  M. Goetz.  Endomicroscopy and targeted imaging of gastric neoplasia. , 2013, Gastrointestinal endoscopy clinics of North America.

[32]  Linas Giniunas,et al.  Scanning fibre-optic microscope , 1991 .

[33]  Paul Fockens,et al.  Probe-based confocal laser endomicroscopy. , 2009, Gastroenterology.

[34]  V. Sharma,et al.  Excited state characteristics of acridine dyes: acriflavine and acridine orange. , 2003, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[35]  M. Kubista,et al.  Absorption and fluorescence properties of fluorescein , 1995 .

[36]  Xiao Wang,et al.  Needle-based fluorescence endomicroscopy via structured illumination with a plastic, achromatic objective , 2013, Journal of biomedical optics.

[37]  Kenneth K Wang,et al.  Endoscopic evaluation and advanced imaging of Barrett's esophagus. , 2011, Gastrointestinal endoscopy clinics of North America.

[38]  B. Hirschowitz.  A personal history of the fiberscope. , 1979, Gastroenterology.

[39]  H. Kiyono,et al.  Epithelial barrier: an interface for the cross‐communication between gut flora and immune system , 2012, Immunological reviews.

[40]  Kartikeya Murari,et al.  A compact fiber-optic SHG scanning endomicroscope and its application to visualize cervical remodeling during pregnancy , 2012, Proceedings of the National Academy of Sciences.

[41]  N. K. Bose,et al.  High resolution image formation from low resolution frames using Delaunay triangulation , 2002, IEEE Trans. Image Process..

[42]  W. Denk,et al.  Miniature random-access fiber scanner for in vivo multiphoton imaging , 2007 .

[43]  Z. Li,et al.  Scanning properties of a resonant fiber-optic piezoelectric scanner. , 2011, The Review of scientific instruments.

[44]  A. Polglase,et al.  A fluorescence confocal endomicroscope for in vivo microscopy of the upper- and the lower-GI tract. , 2005, Gastrointestinal endoscopy.

[45]  J. Edmonson.  History of the instruments for gastrointestinal endoscopy. , 1991, Gastrointestinal endoscopy.

[46]  Timothy D. Soper,et al.  Scanning fiber endoscopy with highly flexible, 1 mm catheterscopes for wide‐field, full‐color imaging , 2010, Journal of biophotonics.