title: Indocyanine-green-loaded microballoons for  biliary imaging in cholecystectomy.
abstract: We encapsulate indocyanine green (ICG) in poly[(D,L-lactide-co-glycolide)-co-PEG] diblock (PLGA-PEG) microballoons for real-time fluorescence and hyperspectral imaging of biliary anatomy. ICG-loaded microballoons show superior fluorescence characteristics and slower degradation in comparison with pure ICG. The use of ICG-loaded microballoons in biliary imaging is demonstrated in both biliary-simulating phantoms and an ex vivo tissue model. The biliary-simulating phantoms are prepared by embedding ICG-loaded microballoons in agar gel and imaged by a fluorescence imaging module in a Da Vinci surgical robot. The ex vivo model consists of liver, gallbladder, common bile duct, and part of the duodenum freshly dissected from a domestic swine. After ICG-loaded microballoons are injected into the gallbladder, the biliary structure is imaged by both hyperspectral and fluorescence imaging modalities. Advanced spectral analysis and image processing algorithms are developed to classify the tissue types and identify the biliary anatomy. While fluorescence imaging provides dynamic information of movement and flow in the surgical region of interest, data from hyperspectral imaging allow for rapid identification of the bile duct and safe exclusion of any contaminant fluorescence from tissue not part of the biliary anatomy. Our experiments demonstrate the technical feasibility of using ICG-loaded microballoons for biliary imaging in cholecystectomy.
authors.affiliation: Ohio State University, Department of Biomedical Engineering, Columbus, Ohio 43210, USA.
authors.forename: Kinshuk
authors.initials: K
authors.lastname: Mitra
authors.forename: James
authors.initials: J
authors.lastname: Melvin
authors.forename: Shufang
authors.initials: S
authors.lastname: Chang
authors.forename: Kyoungjin
authors.initials: K
authors.lastname: Park
authors.forename: Alper
authors.initials: A
authors.lastname: Yilmaz
authors.forename: Scott
authors.initials: S
authors.lastname: Melvin
authors.forename: Ronald X
authors.initials: RX
authors.lastname: Xu
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000033:anatomy & histology; D001659:Biliary Tract / Q000033:anatomy & histology*; D002214:Capsules; D002763:Cholecystectomy; D005456:Fluorescent Dyes; D007208:Indocyanine Green; D007432:Intraoperative Period; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D061848:Optical Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D034421:Sus scrofa
chemical_list: D002214:Capsules; D005456:Fluorescent Dyes; D007208:Indocyanine Green