title: Real-time simultaneous near-infrared fluorescence imaging of bile duct and arterial anatomy.
abstract: BACKGROUND
  We hypothesized that two independent wavelengths of near-infrared (NIR) fluorescent light could be used to identify bile ducts and hepatic arteries simultaneously, and intraoperatively.
  
  
  METHODS
  Three different combinations of 700 and 800 nm fluorescent contrast agents specific for bile ducts and arteries were injected into N = 10 35-kg female Yorkshire pigs intravenously. Combination 1 (C-1) was methylene blue (MB) for arterial imaging and indocyanine green (ICG) for bile duct imaging. Combination 2 (C-2) was ICG for arterial imaging and MB for bile duct imaging. Combination 3 (C-3) was a newly developed, zwitterionic NIR fluorophore ZW800-1 for arterial imaging and MB for bile duct imaging. Open and minimally invasive surgeries were imaged using the fluorescence-assisted resection and exploration (FLARE) surgical imaging system and minimally invasive FLARE (m-FLARE) imaging systems, respectively.
  
  
  RESULTS
  Although the desired bile duct and arterial anatomy could be imaged with contrast-to-background ratios (CBRs) ≥ 6 using all three combinations, each one differed significantly in terms of repetition and prolonged imaging. ICG injection resulted in high CBR of the liver and common bile duct (CBD) and prolonged imaging time (120 min) of the CBD (C-1). However, because ICG also resulted in high background of liver and CBD relative to arteries, ICG produced a lower arterial CBR (C-2) at some time points. C-3 provided the best overall performance, although C-2, which is clinically available, did enable effective laparoscopy.
  
  
  CONCLUSIONS
  We demonstrate that dual-channel NIR fluorescence imaging provides simultaneous, real-time, and high resolution identification of bile ducts and hepatic arteries during biliary tract surgery.
authors.affiliation: Department of Medicine, Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. jfrangio@bidmc.harvard.edu
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Ashitate
authors.forename: Alan
authors.initials: A
authors.lastname: Stockdale
authors.forename: Hak Soo
authors.initials: HS
authors.lastname: Choi
authors.forename: Rita G
authors.initials: RG
authors.lastname: Laurence
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000033:anatomy & histology*; D017081:Cholecystectomy, Laparoscopic / Q000379:methods*; D003199:Computer Systems; D003287:Contrast Media; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005456:Fluorescent Dyes; D006499:Hepatic Artery / Q000033:anatomy & histology*; D007208:Indocyanine Green; D008751:Methylene Blue; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D023421:Models, Animal; D013552:Swine
chemical_list: D003287:Contrast Media; D005456:Fluorescent Dyes; D007208:Indocyanine Green; D008751:Methylene Blue