title: Near-infrared fluorescence imaging of thoracic duct anatomy and function in open surgery and video-assisted thoracic surgery.
abstract: OBJECTIVE
  Chylothorax resulting from thoracic duct damage is often difficult to identify and repair. We hypothesized that near-infrared fluorescent light could provide sensitive, real-time, high-resolution intraoperative imaging of thoracic duct anatomy and function.
  
  
  METHODS
  In 16 rats, 4 potential near-infrared fluorescent lymphatic tracers were compared in terms of signal strength and imaging time: indocyanine green, the carboxylic acid of IRDye 800CW (LI-COR, Lincoln, Neb), indocyanine green adsorbed to human serum albumin, and IRDye 800CW conjugated covalently to human serum albumin. Optimal agent was validated in 8 pigs approaching human size (n = 6 by open surgery with FLARE imaging system [Beth Israel Deaconess Medical Center, Boston, Mass] and n = 2 by video-assisted thoracoscopic surgery minimally invasive [m-FLARE] imaging system [Beth Israel Deaconess Medical Center]). Lymphatic tracer injection site, dose, and timing were optimized.
  
  
  RESULTS
  For signal strength, sustained imaging time, and clinical translatability, the best lymphatic tracer was indocyanine green, which is already Food and Drug Administration approved for other indications. In pigs, a simple subcutaneous injection of indocyanine green into lower leg (≥ 36 μg/kg), provided thoracic duct imaging with onset of about 5 minutes after injection, sustained imaging for at least 60 minutes after injection, and signal-to-background ratio of at least 2. With this technology, normal thoracic duct flow, collateral flow, injury models, and repair models could all be observed under direct visualization.
  
  
  CONCLUSIONS
  Near-infrared fluorescent light could provide sensitive, sustained, real-time imaging of thoracic duct anatomy and function during both open and video-assisted thoracoscopic surgery in animal models.
authors.affiliation: Division of Hematology/Oncology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Mass 02215, USA.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Ashitate
authors.forename: Eiichi
authors.initials: E
authors.lastname: Tanaka
authors.forename: Alan
authors.initials: A
authors.lastname: Stockdale
authors.forename: Hak Soo
authors.initials: HS
authors.lastname: Choi
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
mesh_terms: D000818:Animals; D002916:Chylothorax / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D003952:Diagnostic Imaging / Q000295:instrumentation / Q000379:methods*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000008:administration & dosage; D007208:Indocyanine Green / Q000008:administration & dosage / Q000031:analogs & derivatives; D007259:Infrared Rays; D007279:Injections, Subcutaneous; D008297:Male; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013552:Swine; D013897:Thoracic Duct / Q000293:injuries* / Q000473:pathology; D020775:Thoracic Surgery, Video-Assisted / Q000009:adverse effects / Q000295:instrumentation; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D007208:Indocyanine Green