Indocyanine green videoangiography
Indocyanine green videoangiography (ICG-VA) is an intraoperative technique used to highlight vessels in neurovascular surgery. Visualization of cerebral vessels, their branches, and the surrounding structures are essential during cerebrovascular surgery.
Its application in the study of the vascular pathophysiology in CNS tumors and its role in their surgical management is still rather limited.
An innovation of ICG-VA (i.e., the FLOW 800 algorithm integrated into the surgical microscope) allows a semiquantitative evaluation of cerebral blood flow. The aim of a study of Acerbi et al. was to evaluate for the first time the systematic application of ICG-VA and FLOW 800 analysis during surgical removal of CNS tumors 1).
Indications
Disadvantages
ICG flow alone, but not other structures, can be observed using ICG-VA.
Sato et al., from Fukushima, Japan, Essen, Germany, published in 2018 a novel high-resolution intraoperative imaging system using laser light source for simultaneously visualizing both visible light and near infrared (NIR) fluorescence images of indocyanine green videoangiography (ICG-VA).
They used a novel system for 14 cerebrovascular cases. The operative field was illuminated via an surgical microscope using a novel laser light source with four bands at 464 (blue), 532 (green), 640 (red), and 785 nm (NIR region). The observed light from the operative field was split using a beam splitter cube into visible (420- 660 nm) and NIR fluorescence emission light (832-900 nm). Images from the color video and NIR fluorescence emission windows were merged for visualization on a monitor screen simultaneously. Laser light was compared with xenon light, and both setups were tested for cerebrovascular surgery.
Laser light has numerous advantages over xenon light. The present setup clearly visualized the color operative field with enhanced blood flow. Complete clipping or incomplete clipping with neck remnant or remnant flow into an aneurysm was confirmed in aneurysm surgeries. Feeding artery and draining veins were easily distinguished in case of arteriovenous malformation.
Using the present setup, they can observe the color operative field and enhanced blood flow using ICG in real-time. This setup could facilitate cerebrovascular surgery 2).