Table 7. – Criteria for the identification of intracranial vessels.

Artery	Window	Transducer angle in relation to the skull	Vessel depth	Mean flow velocity	Flow direction
Intrasellar carotid siphon	Orbital	Perpendicular	55-70 mm	40-50 cm/s	Negative
Geniculate carotid siphon	Orbital	Perpendicular	55-70 mm	40-50 cm/s	Negative positive
Suprasellar carotid siphon	Orbital	Perpendicular	55-70 mm	40-50 cm/s	Positive
Ophthalmic	Orbital	Perpendicular	40-60 mm	20 cm/s	Positive
Distal internal carotid	Temporal	Downward	55-70 mm	45 cm/s	Positive
Anterior cerebral	Temporal	Upward and anterior	60-70 mm	60 cm/s	Negative
Middle cerebral	Temporal	Perpendicular	35-60 mm	70 cm/s	Positive
Posterior cerebral (p1)	Temporal	Downward and posterior	55-70 mm	40 cm/s	Positive
Posterior cerebral (p2)	Temporal	Downward and posterior	55-70 mm	40 cm/s	Negative
Vertebral (V4)	Foraminal	Slightly upward and lateral	55-70 mm	40 cm/s	Negative
Proximal basilar	Foraminal	Slightly upward and central	70-120 mm	45 cm/s	Negative
Inferior posterior cerebral	Foraminal	Slightly upward and lateral	40-55 mm	45 cm/s	Positive