The evaluation of carotid artery perfusion with Doppler-ultrasound is based on semiquantitative measurements of blood flow in the terminal branches of the ophthalmic arteries (supratrochlear and supraorbital artery) and the common carotid arteries. Diagnosis is performed with a set of 8 parameters and informs about obstructions in the carotid artery as well as the collateral circulation. The method was applied on 1500 patients of whom 340 underwent angiography and has proved to be about 90% reliable. Its value in carotid artery surgery was evaluated with 62 extracranial reconstructive operations on 55 patients and 35 iatrogene anastomoses between the temporal superficial and a branch of the middle cerebral artery on 35 patients.