title: Preclinical study of near-infrared-guided sentinel lymph node mapping of the porcine lung.
abstract: BACKGROUND
  The presence of lymph node metastasis is the most important prognostic factor in early non-small cell lung cancer. Our objective was to develop a rapid, simple, and reliable method for thoracic sentinel lymph node (SLN) identification using near-infrared fluorescence imaging and clinically available contrast agents.
  
  
  METHODS
  Indocyanine green (ICG) reconstituted in saline, human serum albumin, human fresh frozen plasma, and autologous porcine plasma was evaluated for optimal formulation and dosing for SLN within porcine lungs. Animals were imaged using the fluorescence-assisted resection and exploration for surgery imaging system. The SLN identification rate, time to identification and fluorescence intensity of the SLN, bronchus, and background were measured.
  
  
  RESULTS
  The SLN identification rates varied widely, ranging from 33% to 100% as a function of the carrier used for ICG reconstitution. No significant difference was noted in SLN fluorescence intensity; however, bronchial intensity was significantly higher with ICG: albumin, which resulted in the lowest rate of SLN identification. Subsequent evaluation with 125 μM and 250 μM ICG:porcine plasma resulted in identification of strongly fluorescent SLNs, with identification rates of 93% and 100% and median signal-to-background ratios of 8.5 and 12.15, respectively, in less than 2 minutes in situ.
  
  
  CONCLUSIONS
  Near-infrared fluorescence imaging with ICG is a reliable method for SLN mapping in the lung with high sensitivity. Mixing of ICG with plasma resulted in strong SLN fluorescence signal with reliable identification rates.
authors.affiliation: Division of Thoracic Surgery, Brigham & Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Onkar V
authors.initials: OV
authors.lastname: Khullar
authors.forename: Denis M
authors.initials: DM
authors.lastname: Gilmore
authors.forename: Aya
authors.initials: A
authors.lastname: Matsui
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Ashitate
authors.forename: Yolonda L
authors.initials: YL
authors.lastname: Colson
mesh_terms: D000818:Animals; D004396:Coloring Agents; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D007208:Indocyanine Green; D008168:Lung / Q000473:pathology*; D008175:Lung Neoplasms / Q000175:diagnosis / Q000556:secondary*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D009374:Neoplasms, Experimental / Q000175:diagnosis*; D015203:Reproducibility of Results; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D013552:Swine
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green