Table 2.

Mean cerebral blood flow velocity (cm/s) related to age

Artery	Age 20-40 yr	Age 40-60 yr	Age > 60 yr
Anterior cerebral artery	56-60	53-61	44-51
Middle cerebral artery	74-81	72-73	58-59
Posterior cerebral artery P1	48-57	41-56	37-47
Posterior cerebral artery P2	43-51	40-57	37-47
Vertebral artery	37-51	29-50	30-37
Basilar artery	39-58	27-56	29-47