Color Duplex Measurement of Cerebral Blood Flow Volume in Healthy Adults

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Abstract
Global cerebral blood flow (CBF) is an important yet largely unknown quantity in the treatment of neurological intensive care patients. Color duplex sonography of the extracranial cerebral arteries can be used to measure global CBF volume directly at the bedside. To establish reference data on global CBF volume and to test the influence of sex and age on this parameter, a prospective study was performed in a group of 78 healthy adults aged 20 to 85 years (39 women, 39 men; mean age, 52+/-19 years in either sex). The common, external, and internal carotid arteries and the vertebral arteries were examined with the use of a 7.0-MHz transducer of a computed sonography system. Angle-corrected time-averaged flow velocity and the diameter of the vessel were measured. Intravascular flow volumes were calculated as the product of angle-corrected time-averaged flow velocity and the cross-sectional area of the circular vessel. CBF volume was determined as the sum of flow volumes in the internal carotid and vertebral arteries of both sides. From 20 to 85 years of age, CBF volume decreased significantly (P</=0.0001), on average by approximately 3 mL/min per year. There were no sex-linked differences in CBF volume. The mean relative contributions of the internal carotid artery and the vertebral arteries to global CBF volume remained constant with age (76% versus 24%). The reference data on CBF volume established for the groups aged 20 to 39 years, 40 to 59 years, and 60 to 85 years were 727+/-102, 656+/-121, and 603+/-106 mL/min, respectively. The data presented here provide additional information on the natural development of global cerebral perfusion in "benign aging." CBF volume reference data for different age groups were also established. These data provide a basis for the clinical application of CBF volume measurements at the bedside, especially in the monitoring of CBF volume in neurological intensive care patients.