Duplex transcranial sonography is a non-invasive examination method which makes possible direct visualization of basic segments of arteries of the circle of Willis along with angular correction during dopplerometric examinations which provides more accurate information on actual flow rates. The authors examined a total of 435 subjects with other than cerebrovascular diseases or healthy subjects aged 11 to 90 years. The authors assessed the maximum flow rate (peak systolic velocity – PSV), the velocity at the end of the diastole (end diastolic velocity – EDV) and the resistance index (RI) in the following arteries: horizontal M1 section of the a. cerebri media (ACM), precommunicating A1 section of the a. cerebri anterior (ACA), precommunicating section P1 of the a. cerebri posterior (ACP) in intracranial portions of the vertebral artery (AV) and a. basilaris (AB). The authors found mean angular corrected values of PSV, EDV and RI, incl. values of standard deviations (SD) for the following age groups: under 20 years, 21–30 years, 31–40 years, 41–50 years, 51–60 years, 61–70 years, 71–90 years. They observed a gradual decline of flow rates and increased resistance in relation to age and higher PSV in some arteries in women before the menopause. Assessment of mean flow rates in the cerebral arteries in the healthy population is essential for the further application of transcranial duplex sonography in cerebrovascular diseases.

        Key words: transcranial duplex sonography, mean flow rates