Transcranial Doppler Ultrasound: A Review of the Physical Principles and Major Applications in Critical Care

Table 1

Insonation characteristics of the cerebral vasculature. Adapted from Nicoletto and Burkman [3]. Permission obtained; copyright owner ASET (American Society of Electroneurodiagnostic Technologists), the Neurodiagnostic Society.

Artery	Acoustic window	Probe angle	Depth; (mm)	Flow direction	Resistance	Adult MFV; (cm/sec)
ECICA	Retromandibular	Superior-medial	45–50	Away	Low	30±9
MCA	Middle transtemporal	Straight/Anterior-superior	30–65	Toward	Low	55±12
ACA	Middle transtemporal	Straight/Anterior-superior	60–75	Away	Low	50±11
PCA—segment 1	Posterior transtemporal	Straight/Posterior	60–70	Toward	Low	39±10
PCA—segment 2	Posterior transtemporal	Straight/Posterior-superior	60–70	Away	Low	40±10
BA	Suboccipital	Superior	80–120	Away	Low	41±10
VA	Suboccipital	Superior lateral	60–75	Away	Low	38±10
OA	Transorbital	Straight	45–55	Toward	High	21±5
Supraclinoid ICA	Transorbital	Superior	65–80	Away	Low	41±11
Parasellar ICA	Transorbital	Inferior	65–80	Toward	Low	47±14

(ECICA: extracranial internal carotid artery, MCA: middle cerebral artery, ACA: anterior cerebral artery, PCA: posterior cerebral artery, BA: basilar artery, OA: ophthalmic artery).