title: Predicting the survival of experimental ischaemic small bowel using intraoperative near-infrared fluorescence angiography.
abstract: BACKGROUND
  Predicting the long-term viability of ischaemic bowel during surgery is challenging. The aim was to determine whether intraoperative near-infrared angiography (NIR-AG) of ischaemic bowel might provide metrics that were predictive of long-term outcome.
  
  
  METHODS
  NIR-AG using indocyanine green was performed on 24 pigs before, and after inducing bowel ischaemia to determine the feasibility of NIR-AG for detecting compromised perfusion. Contrast-to-background ratio (CBR) over time was measured in regions of interest throughout the bowel, and various metrics of the CBR-time curve were developed. Sixty rat small bowels, with or without strangulation, were imaged during surgery and on day 3 after operation. CBR metrics and clinical findings were assessed quantitatively for their ability to predict animal survival, histological grade of ischaemic injury and visible necrosis on day 3.
  
  
  RESULTS
  In ischaemic pig small bowel, various qualitative and quantitative CBR metrics appeared to correlate with bowel injury as a function of distance from normal bowel. In rats, intraoperative clinical assessment showed high specificity but low sensitivity for predicting outcome on day 3 after operation. Qualitative patterns of the CBR-time curve, such as absence of an arterial inflow peak and presence of a NIR filling defect, resulted in better prediction of survival (90 per cent), histological grade (85 per cent) and visible necrosis on day 3 (92 per cent).
  
  
  CONCLUSIONS
  Survival of ischaemic bowel was predicted by intraoperative NIR-AG with greater accuracy than clinical evaluation alone.
authors.affiliation: Division of Haematology/Oncology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
authors.forename: A
authors.initials: A
authors.lastname: Matsui
authors.forename: J H
authors.initials: JH
authors.lastname: Winer
authors.forename: R G
authors.initials: RG
authors.lastname: Laurence
authors.forename: J V
authors.initials: JV
authors.lastname: Frangioni
mesh_terms: D000818:Animals; D004396:Coloring Agents; D005240:Feasibility Studies; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D007208:Indocyanine Green; D007415:Intestinal Obstruction / Q000601:surgery; D007421:Intestine, Small / Q000098:blood supply*; D007432:Intraoperative Period; D007511:Ischemia / Q000601:surgery*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D016019:Survival Analysis; D013552:Swine
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green