Objective: The aim of the present study is to assess whether the technique of surgical microscope-based indocyanine green videoangiography (ICG-VA) and the FLOW800 system are efficient for hemodynamic evaluation during carotid endarterectomy (CEA). Methods: 20 CEAs for 19 patients were performed from January to July 2011. Before and after endarterectomy, ICG was injected intravenously. After the procedure, ICG-VA was analyzed by FLOW800. Regions of interest were the common carotid artery, the plaque, the internal carotid artery, and the external carotid artery to evaluate changes in each intensity value. Results: The distal end of carotid plaque and the proximal end were identified in 85% of CEAs and 78.9% of cases. In 5 cases (26.3%) with more severe stenosis (&gt
90%), the decrease of blood flow intensity in the internal carotid artery was delayed before endarterectomy. After endarterectomy, the finding was improved in all the 5 cases. After the endarterectomy, the intensity values in the common carotid artery, the plaque, the internal carotid artery, and the external carotid artery had increased 162±129, 337±212, 139±151 and 177±143. Especially in the value of the plaque, there was a great improvement. Conclusions: ICG-VA provides information of the plaque location and the patency of the arterial vessel during CEA. Using FLOW800, semiquantitive information of hemodynamics was able to be acquired, especially for the case of severe stenosis with collapse of the internal carotid artery.