Ch 13 Transcranial Doppler Flashcards
What is transcranial doppler (TCD)?
Imaging technique of the intracranial ICA + vessels within the circle of willis
What vessels are in the circle of willis?
ICA, MCA, vertebral arteries, etc.
(not ECA b/c it does not supply blood to brain)
Which blood vessels connect the extracranial cerebrovascular system with the circle of willis?
ICA’s + vertebral arteries
What probe should be used for TCD?
-Low frequency (2-5 MHz)
-Phased array probe
What are the names of the acoustic windows?
-Temporal (m/c)
-Occipital
-Opthalamic (l/c)
What is the m/c acoustic window used?
Temporal
What vessels are imaged from the temporal window?
-MCA
-ACA (anterior cerebral artery)
-Terminal ICA
-PCA (posterior cerebral artery)
What vessels are imaged from the foramen magnum/suboccipital window?
-Both vertebral arteries
-Basilar artery
What vessels are imaged from the orbital window?
Opthalamic artery
What other considerations should be given when imaging from the orbital window?
Transmit power should be reduced to 10%
What TAPV velocities do we expect to see in the MCA, ACA, PCA + basilar arteries?
MCA: 60 cm/s
ACA: 50 cm/s
PCA: 40 cm/s
Basilar: 40 cm/s
What direction of flow should we see in the MCA?
Forward flow above the baseline in the ipsilateral MCA
What is the standard probe orientation from the temporal window?
Indicator should point towards pt’s nose
What makes TCD imaging challenging?
-Imaging through bone
-Size of vessels
What is TAPV?
-Time average peak velocity
-It is the peak velocity throughout a cardiac cycle + its average
