A 55-year-old man presented with intracerebral hemorrhage and his angiographic evaluation revealed a S-M Grade 4 AVM in his right parietal area [] and was selected for microsurgery. As demonstrated in Figure –, ICG studies are helpful in different stages of the surgery. After opening the dura, the AVM is observed [], and ICG-VA shows the precise anatomy of the vessels []. To distinguish arteries from veins, this image was further reinforced by the color-coded FLOW 800 [] where one can observe the feeding artery in red and the draining vein in blue. This visual color map featured an overview of blood flow dynamics and facilitated identifying the feeding arteries at a single glance. As the operation goes on, changes of blood flow in AVM can be tracked by further color-coded images []. When the resection was completed, a final ICG-VA depicted total AVM removal with no residual nidus [].
Figure – shows a 62-year-old man diagnosed with a cerebellar AVM with feeders from left superior and posterior inferior cerebellar arteries. After exposing the lesion, ICG-VA demonstrates AVM vessels []. illustrates the same view after being rendered by the FLOW 800. Early appearing blood flow is showed in red and late appearing flow in blue. After selecting ROIs for the software, semi-quantitative characteristics of the blood flow in desired vessels were analyzed and demonstrated in curves by the FLOW 800 []. After microsurgical resection of the AVM was complete, ICG-VA showed no remnant of the AVM []. Visual color map showed hemodynamic changes after AVM resection [] in contrast with preresection status []. Furthermore, analytical graphs show changes in flow parameters immediately after AVM resection [Figure and ]. To make it easy to understand, we removed all curves of except for one to demonstrate image analysis performed with ImageJ software []. Time to peak, rise time, and MFI are all showed on the curve. Although CBFI is also calculated, we should notice that this curve is derived from a venous blood flow not brain parenchyma and this index is demonstrated as an example to explain its calculation.