Chapter 21- Transcranial Dopplers Flashcards
The opthalmic artery branches off of what vessel?
terminal ICA
The frontal artery arises from what artery?
The opthalmic artery
The frontal artery supplies what part of the head?
forehead
The supraorbital artery arises from what artery?
the opthalmic artery
What is TCD’s good for detecting?
Brain death, emboli, subarachnoid hemorrhage, stenosis, occlusion
What is the main limitation with transcranial dopplerS?
The penetration of the temporal bone is not good.
What are the three acoustic windows we use for TCDs?
transtemporal, transorbital, and suboccipital
What are we measuring during a TCD?
Very important.
the Time Averaged Max Velocity(TAMV) OR MEAN VELOCITY
we are NOT NOT NOT doing peak systolic. only the mean velocity.
In what order of technique should we go in when doing TCD
remember the techniques are : Transorbital, transforamenal, and transtemporal.
1) Transtemporal to get the ICA, MCA, ACA, and PCA
2) Ipsilateral Transorbital to find opthalmic and carotid siphon
2) Transforamenal to get distal vertebral and basilar artery.
The following vessels should be seen in the Transtemporal view
(There is 4 of them)
Middle cerebral artery, terminal ica, Anterior communicating artery, and posterior cerebral artery
The following vessels should be seen in the transopthalmic view
There is 2
Opthalmic and ICA
Which vessels should be seen in the subforamenal view?
Vertebral and Basilar
The verebral and basilar arteries should have flow coming towards or away transducer?
Away
The middle cerebral artery should have flow going towards or away from transducer?
towards
Which vessel of the COW has the highest velocity?
middle cerebral
What are some factors that can affect the intracranial blood flow?
age, sex, hematocrit, oxygen levels.
The highest mean in all of these vessels shouldn’t get any higher than 55 TAMV cm/sec
True or False
True
In an intracranial stenosis, the velocities are going to be higher or lower?
Higher
Vasospasms most often are seen in which vessel?
Middle cerebral artery (mean velocity >120 cm/sec
When a patient is brain dead, the blood flow goes from low resistant to high resistant, so we will see NO diastolic flow in ICA, MCA, or ACA.
True or False
True. The brain is dying so it doesnt need the constant flow that low resistant provides, there fore becomes low-resistant
IMPORTANT!!!!
We can detect micro-emboli. Typically it will sound like a moan or chip. What will we see on the waveform?
a random line will be seen with the chirp noise.
Where does this micro-emboli come from?
Carotid stenosis or a cardiac source
What is an example of the cardiac source micro-emboli can come from?
The patent Foramen Ovale-
this alows blood and emboli to travel from the venous side to the arterial side in the left atrium.
MCA stands for ?
Middle cerebral artery
The middle cerebral artery can be seen best through which window?
Transtemporal, transorbital or transforamenal
temporal (side of head)
When imaging the middle cerebral artery, what depth should we have our transducer at?
30-60
When imaging the middle cerebral artery, what direction will the flow be coming in? and how should we angle our probe?
The flow will be coming towards (highest velocity of all) and we should have it anterior and superior
The terminal ICA can be seen best through which window?
Transtemporal, transorbital or transforamenal
transtemporal
When imaging the terminal ICA, what depth should we have our transducer?
55-65 (thnk its deeper than the middle cerebral artery so we need to go further than that)
What direction will the terminal ICA be going in a transtemporal view?
bidrectional. angle superior and anterior. just deeper than MCA
The Anterior cerebral artery can be seen best through which window?
Transtemporal, transorbital or transforamenal
Transtemporal view
When imaging the anterior cerebral artery, what depth should we be at?
60-80 (think it is deeper than the middle cerebral and terminal ICA in the brain so we need to go deeper)
When imaging the anterior cerebral artery from a transtemporal approach, what direction will the flow be going?
away from transducer.
The posterior cerebral artery can be seen best through which window?
Transtemporal, transorbital or transforamenal
Transtemporal
When imaging the posterior cerebral artery, what depth should we use?
60-70
When imaging the posterior cerebral artery from the temporal approach, should we angle anteriorly or posteriorly?
POSTERIORLY (HINT POSTERIOR cerebral artery)
When imaging the posterior cerebral artery from a transtemporal approach, which direction will the flow be going?
towards
The opthalmic artery can be seen best through which window?
Transtemporal, transorbital or transforamenal
Transorbital ( think opthalmic has to due with the EYE- hint orbital/eye)
When imaging the opthalmic artery, what depth should we be using?
40-60
When imaging the opthalmic artery from an transorbital approach, what direction will the flow be going?
TOWARDS.
When imaging the opthalmic artery from a transorbital approach, should we angle medially or laterally?
medially
The vertebral artery can be seen best through which window?
Transtemporal, transorbital or transforamenal
transforamenal
When imaging the vertebral artery, what depth should be at ?
60-90
When imaging the vertebral artery from transformenal approach, what direction will the flow be coming from?
away?
When imaging the vertebral artery from a transforamenal approach, how should we angle the probe?
right and left of midline
The basilar artery can be seen best through which window?
Transtemporal, transorbital or transforamenal
foramenal
When imaging the basilar artery from a transforamenal approach, what direction will the flow be coming from?
AWAY.
When imaging the basilar artery from a transforamenal approach, how should we angle our probe?
Midline
When we see velocities much higher than normal for each vessel, what should we suspect?
STENOSIS
What is the normal velocity for the middle cerebral artery?
55 +/- 12
What is the normal velocity for the terminal ICA?
55 +/- 12
What is the normal velocity for the anterior cerebral artery?
50 +/- 11
What is the normal velocity for the posterior cerebral artery?
39 +/- 10
What is the normal velocity for the ophthalmic artery?
21 +/- 10
What is the normal velocity for the vertebral artery?
38 +/- 10
What is the normal velocity for the basilar artery?
41 +/- 10
TRUE OR FALSE
We use the MEAN VELOCITY not the peak systolic velocity when doing these TSDs?
true true!!!!
Important to remember
In what two arteries do we often see occlusions in Transcranial dopplers/
ICA or Middle Cerebral artery
the anterior cerebral artery and its branches feed which lobes of the brain?
frontal, occiptal, parietal (can be more than one)
parietal and frontal lobes
What two branches in the brain feed the brain stem and cerebellum?
basilar and vertebral
Which branch of the circle of willis supplies the CSP and corpus collosum with blood supply?
anterior cerebral artery (midline anterior brain location)