title: Use of in vivo near-infrared laser confocal endomicroscopy with indocyanine green to detect the boundary of infiltrative tumor.
abstract: OBJECTIVE
  Infiltrative tumor resection is based on regional (macroscopic) imaging identification of tumorous tissue and the attempt to delineate invasive tumor margins in macroscopically normal-appearing tissue, while preserving normal brain tissue. The authors tested miniaturized confocal fiberoptic endomicroscopy by using a near-infrared (NIR) imaging system with indocyanine green (ICG) as an in vivo tool to identify infiltrating glioblastoma cells and tumor margins.
  
  
  METHODS
  Thirty mice underwent craniectomy and imaging in vivo 14 days after implantation with GL261-luc cells. A 0.4 mg/kg injection of ICG was administered intravenously. The NIR images of normal brain, obvious tumor, and peritumoral zones were collected using the handheld confocal endomicroscope probe. Histological samples were acquired from matching imaged areas for correlation of tissue images.
  
  
  RESULTS
  In vivo NIR wavelength confocal endomicroscopy with ICG detects fluorescence of tumor cells. The NIR and ICG macroscopic imaging performed using a surgical microscope correlated generally to tumor and peritumor regions, but NIR confocal endomicroscopy performed using ICG revealed individual tumor cells and satellites within peritumoral tissue; a definitive tumor border; and striking fluorescent microvascular, cellular, and subcellular structures (for example, mitoses, nuclei) in various tumor regions correlating with standard clinical histological features and known tissue architecture.
  
  
  CONCLUSIONS
  Macroscopic fluorescence was effective for gross tumor detection, but NIR confocal endomicroscopy performed using ICG enhanced sensitivity of tumor detection, providing real-time true microscopic histological information precisely related to the site of imaging. This first-time use of such NIR technology to detect cancer suggests that combined macroscopic and microscopic in vivo ICG imaging could allow interactive identification of microscopic tumor cell infiltration into the brain, substantially improving intraoperative decisions.
authors.affiliation: Neurosurgery Research Laboratory, Division of Neurological Surgery, Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013, USA.
authors.forename: Nikolay L
authors.initials: NL
authors.lastname: Martirosyan
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Cavalcanti
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Eschbacher
authors.forename: Peter M
authors.initials: PM
authors.lastname: Delaney
authors.forename: Adrienne C
authors.initials: AC
authors.lastname: Scheck
authors.forename: Mohammed G
authors.initials: MG
authors.lastname: Abdelwahab
authors.forename: Peter
authors.initials: P
authors.lastname: Nakaji
authors.forename: Robert F
authors.initials: RF
authors.lastname: Spetzler
authors.forename: Mark C
authors.initials: MC
authors.lastname: Preul
mesh_terms: D000818:Animals; D001706:Biopsy; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery*; D002533:Cerebral Angiography / Q000295:instrumentation / Q000379:methods; D004396:Coloring Agents; D003399:Craniotomy; D004195:Disease Models, Animal; D005260:Female; D005909:Glioblastoma / Q000473:pathology* / Q000601:surgery*; D007208:Indocyanine Green; D007259:Infrared Rays; D007432:Intraoperative Period; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods; D018715:Microscopy, Video / Q000295:instrumentation / Q000379:methods; D008904:Miniaturization
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green