In a prospective study of the natural development of total cerebral blood flow volume (CBFV), the common, external and internal carotid and vertebral arteries were examined in 94 healthy children and adolescents between 3 and 18 years of age (sex and age evenly distributed) using a 7.0-MHz transducer of a computed sonography system. Intravascular flow volumes were calculated with the product of angle-corrected time-averaged flow velocity and the cross-sectional area of the vessel. CBFV was determined as the sum of flow volumes in the internal carotid and vertebral arteries of both sides. CBFV increased significantly between 3 and 6.5 years of age (from 687 +/- 85 to 896 +/- 110 ml/min; age correlation, p < or = 0.01) and declined thereafter (p < or = 0.001) to a constant level of approximately 700 ml/min at 15 years of age. There was no difference in CBFV between sexes. The proportion of bilateral vertebral artery flow volume in total CBFV decreased significantly between the ages of 3 and 18 years (p < or = 0.001). As the flow volumes of the external carotid arteries increased markedly from childhood to adulthood, flow volumes of the common carotid arteries were not representative of CBFV. Intrasession test-retest correlation of CBFV was high (r = 0.89, p < or = 0.0001). Reference data for the childhood years presented here and previously described results from healthy adults allow us to outline the natural evolution of CBFV in humans. The reliability of the method has already been demonstrated. Thus, it may now be introduced into clinical application.