title: A quantitative method for evaluating local perfusion using indocyanine green fluorescence imaging.
abstract: BACKGROUND
  The purpose of this study is to introduce a new method, indocyanine green fluorescence imaging (ICG-FI), as an adjunct to distal pressure measurements in patients with peripheral arterial disease and symptomatic lower limb ischemia.
  
  
  METHODS
  A total of 34 patients with peripheral arterial disease, including 11 with claudication (Fontaine II), 7 with rest pain (FIII), and 16 with an ulcer or gangrene (FIV), were enrolled. After an intravenous injection of ICG (0.1 mg/kg), foot perfusion was recorded by an infrared light camera. Fluorescence intensity was plotted on a time-intensity curve using recorded images, allowing the calculation of new parameters. Severity of ischemia was assessed as the duration between the rising point and half value of maximum brightness (T½). The difference in the fluorescence intensity between 10 seconds after the rising point and baseline (PDE10) was compared with the transcutaneous oxygen pressure (tcPO2) at the same site (n=51).
  
  
  RESULTS
  Median T½ was 23 seconds in FII, 41 seconds in FIII (P<0.05), and 17 seconds in FIV patients. PDE10 correlated moderately with tcpO2 (r2=0.5). A cut-off value (PDE10=28) predicted a critically ischemic limb (FIII and FIV), defined as tcpO2<30 mm Hg with a sensitivity of 100% and specificity of 86.6%.
  
  
  CONCLUSIONS
  Local tissue perfusion can be quantitatively evaluated by using ICG fluorescence imaging. It is a safe, fast, noncontact method of imaging, which may be useful even at the ulcer itself and in the circumferential area.
authors: Department of Vascular and Applied Surgery, Tokyo Medical and Dental University, Graduate School, Tokyo, Japan. Electronic address: terasaki.srg1@tmd.ac.jp.
authors: Hiroaki
authors: H
authors: Terasaki
authors: Yoshinori
authors: Y
authors: Inoue
authors: Norihide
authors: N
authors: Sugano
authors: Masatoshi
authors: M
authors: Jibiki
authors: Toshihumi
authors: T
authors: Kudo
authors: Mauri
authors: M
authors: Lepäntalo
authors: Maarit
authors: M
authors: Venermo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D001785:Blood Gas Monitoring, Transcutaneous; D005260:Female; D005456:Fluorescent Dyes / Q000008:administration & dosage; D005528:Foot / Q000098:blood supply*; D005734:Gangrene; D006801:Humans; D007208:Indocyanine Green / Q000008:administration & dosage; D007275:Injections, Intravenous; D007383:Intermittent Claudication / Q000175:diagnosis / Q000503:physiopathology; D007511:Ischemia / Q000175:diagnosis* / Q000503:physiopathology; D007871:Leg Ulcer / Q000175:diagnosis / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D061848:Optical Imaging; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D007208:Indocyanine Green