title: Identification of liver metastases with probe-based confocal laser endomicroscopy at two excitation wavelengths.
abstract: Metastasis of colorectal cancer to the liver is the most common indication for hepatic resection in a western population. Incomplete excision of malignancy due to residual microscopic disease normally results in worse patient outcome. Therefore, a method aiding in the real time discrimination of normal and malignant tissue on a microscopic level would be of benefit.
  
  
  
  The ability of fluorescent probe-based confocal laser endomicroscopy (pCLE) to identify normal and malignant liver tissue was evaluated in an orthotopic murine model of colorectal cancer liver metastasis (CRLM). To maximise information yield, two clinical fluorophores, fluorescein and indocyanine green (ICG) were injected and imaged in a dual wavelength approach (488 and 660 nm, respectively). Visual tissue characteristics on pCLE examination were compared with histological features. Fluorescence intensity in both tissues was statistically analysed to elucidate if this can be used to differentiate between normal and malignant tissue.
  
  
  
  Fluorescein (488 nm) enabled good visualisation of normal and CRLM tissue, whereas ICG (660 nm) visualisation was limited to normal liver tissue only. Fluorescence intensity in areas of CRLM was typically 53-100% lower than normal hepatic parenchyma. Using general linear mixed modelling and receiver operating characteristic analysis, high fluorescence intensity was found to be statistically more likely in normal hepatic tissue.
  
  
  
  Real time discrimination between normal liver parenchyma and metastatic tissue with pCLE examination of fluorescein and ICG is feasible. Employing two (rather than a single) fluorophores allows a combination of qualitative and quantitative characteristics to be used to distinguish between hepatic parenchyma and CRLM. Lasers Surg. Med. 49:280-292, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Division of Surgery & Interventional Science, University College London, Floor 9, Royal Free Hospital, London, NW3 2QG, UK.
authors.forename: Crispin
authors.initials: C
authors.lastname: Schneider
authors.affiliation: UCL Centre for Advanced Biomedical Imaging, Paul O'Gorman Building, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Johnson
authors.affiliation: Division of Surgery & Interventional Science, University College London, Floor 9, Royal Free Hospital, London, NW3 2QG, UK.
authors.forename: Kurinchi
authors.initials: K
authors.lastname: Gurusamy
authors.affiliation: Department of Tissue Engineering and Biophotonics, King's College London, Dental Institute-Central Office, Floor 18, Guy's Tower, Guy's Hospital, London, SE1 9RT, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cook
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, UK.
authors.forename: Adrien E
authors.initials: AE
authors.lastname: Desjardins
authors.affiliation: Centre for Medical Image Computing, University College London, The Front Engineering Building, Floor 3, Malet Place, London, WC1E 7JE, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Hawkes
authors.affiliation: Division of Surgery & Interventional Science, University College London, Floor 9, Royal Free Hospital, London, NW3 2QG, UK.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Davidson
authors.affiliation: UCL Centre for Advanced Biomedical Imaging, Paul O'Gorman Building, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Walker-Samuel
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D004195:Disease Models, Animal; D005260:Female; D019793:Fluorescein; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary*; D051379:Mice; D008815:Mice, Inbred Strains; D018613:Microscopy, Confocal / Q000379:methods*; D011897:Random Allocation; D012016:Reference Values
chemical_list: D019793:Fluorescein
keywords: confocal laser endomicroscopy; fluorescein; fluorescence microscopy; indocyanine green; liver metastases; virtual histology