Utilization of indocynanine green fluorescent imaging (ICG-FI) for the assessment of microperfusion in vascular medicine

Figure 1:. Indocyanine green fluorescent imaging (IDG-FI): After intravenous injection, the region of interest is illuminated with near-infrared light (785 nm). The fluorescence emission of the excited dye is detected by an infrared-sensitive charge-coupled device camera system (dynamic range 54 dB) equipped with a band pass filter for the selective transmission of light at the emission maximum of ICG (830 nm).

Figure 2:. Left: experimental setting of ICG-FI. The tissue in the region of interest is illuminated with near-infrared light at a wavelength of 785 nm with a total output of 80 mW in a field of view of 10 cm in diameter (1 mW/cm2) operating at a distance of approximately 20 cm above tissue. The fluorescence emission of the excited dye is detected by an infrared-sensitive charge-coupled device (CCD) camera system (dynamic range 54 dB). Right: ICG-FI before stenosis (above) and myocardial perfusion during flow-limiting coronary stenosis of high severity (lower).

Figure 3:. Setting for ICG-FI measurements. The camera is positioned perpendicular to area of interest. ICG-FI is captured when all light sources are removed.

Figure 4:. Green time-intensity curve corresponding to preoperative ICG-FI measurement. Purple time-intensity curve corresponding to postoperative ICG-FI measurement. Yellow line (linear regression trendline) corresponding to SFI manually fitted to the maximum incline of the curves. Reprinted from Publication Vasa, 46/5, H. C. Rieß et al., A new tool for fluorescent imaging, pp. 383–388. Copyright Hogrefe Publishing Corp. Reproduced with permission.

Figure 5:. Microembolization of digitus I of the left foot. Before (left side) and after 10 days of treatment with Heparin and Alprostadil (Prostavasin).

Figure 6:. Induced mesenteric ischemia in a porcine model on the left. On the right side, the corresponding ICG-FI picture with total loss of fluorescence in the left loop.