Near-infrared fluorescence angiography with Indocyangreen
(NIRF)
Near-infrared fluorescence angiography (NIRF) provides real-time
visualization of vessel structure during surgical procedures. This uses
near-infrared fluorescence technology to visualize detailed information
about the blood vessels. This is done by injecting a dye -mostly-
indocyanine green (ICG) intravenously - binding to albumin in the plasma
[67] and capturing images with near-infrared light. NIRF delivers
intraoperative visualization of vascular structures, leveraging advanced
near-infrared fluorescence technology. By intravenously administering
indocyanine green (ICG), NIRF enables real-time imaging of intricate
blood vessel networks, as meticulously detailed in the Meta-analysis
conducted by Smit et al. This timeframe varies between 12 and 27
seconds. [68]
Depending on the available system, a movable arm allows flexible
positioning of light sources and optics over the surgical area. The
captured images can be displayed either as still images or as movies on
monitors. This technique has proven successful in both preclinical
research and clinical applications from vascular surgery over Plastic
surgery [67] to breast reconstruction after mastectomy. [69]
Perfusion patterns visualized with NIRF imaging are quantified using
time-intensity curves, providing various parameters for statistical
analysis and visualization. These parameters, including Ingress, Egress,
Fluorescence intensity, Tmax, T1/2, and
others, allow for standardized quantification of tissue perfusion using
NIRF imaging, aiding in clinical decision-making and optimizing surgical
outcomes. [67]
It can also be used to assess tissue flap perfusion during surgical
planning in the location of perforators to predict tissue flap survival
and reduce the risk of necrosis areas. [69-72] As described in the
study by Lee et al, near-infrared fluorescence angiography enables
real-time visualization of vessel structure intraoperatively.
Near-infrared fluorescence angiography can be used in the course of flap
planning of perforating vessels and a study by Matsiu et al was able to
predict the survival of submental flaps via ICG injections at 0, 0.5,
24, 48, and 72 hours postoperatively via the percentage area of vital
perfusing flap areas and predict necrosis areas after 72 hours. [72]
In a study by Lohman et al, the above technology application had a high
sensitivity of 90 per cent in intraoperative flap planning in terms of
blood flow indication. [73] Furthermore, as described by Ludolph et
al, this technique can be a viable tool for perfusion monitoring over
longer periods and can be used to evaluate free flap-Autonomization.
[21]