Week 4 Part 2

Question 1

Transcranial Doppler is used to

Answer 1

assess cerebral hemodynamics and evaluate intracranial cerebrovascular disease

Question 2

What’s used in TCD

Answer 2

power Doppler, duplex sonography and contrast agents

Question 3

Transcranial instruments have a ______ bandwidth

Answer 3

Lower

Question 4

What is the transmitting power on TCD instruments

Answer 4

b/w 10 and 100mW/cm/sec

Question 5

Focusing of beam is _______ to _______ from probe

Answer 5

40-60mm

Question 6

What type of transducer is used with TCD?

Answer 6

2MHz pulsed range gated Doppler device

Question 7

What are the indications for a TCD? Part 1

Answer 7

Detection of intracranial stenosis and occlusions in the major arteries
Evaluation of intracranial hemodynamics and collateral flow where there is extracranial disease
Monitoring of intracranial vessel recanalization in acute stroke
Monitoring intracranial hemodynamics after:
Hemorrhage
Endarterectomy/angioplasty

Question 8

What are the indications for a TCD? Part 2

Answer 8

Detection of right to left shunts
Detection of cerebral microemboli
During functional tests:
Stimulation with vasoconstrictive drugs
External stimulation of visual cortex
Before neurosurgery
During open heart surgery

Question 9

The ACA has __ segments.

Answer 9

2 – A1 and A2

Question 10

Carotid Siphon (just proximal to ICA intracranial branches) has ____ segments.

Answer 10

3 – C1, C2, C3

Question 11

Opthalamic artery branches at the junction of _____ and _____

Answer 11

C2 and C3

Question 12

MCA has ___ segments.

Answer 12

M1 and M2

Question 13

PCA has ___ segments.

Answer 13

P1 and P2

Question 14

Segments that are labelled 1 are closest to ____ ________ __ ____ _________.

Answer 14

The midline of the brain

Question 15

What are the windows for TCD?

Answer 15

temporal
orbital
submandibular
suboccipital

Question 16

Submandibular approach:

Answer 16

probe is directed towards proximal intracranial ICA

window- below mandible at the angle using the carotid triangle

Question 17

We use the submandibular approach to visualize the _______ ________ ____.

Answer 17

proximal intracranial ICA

Question 18

Suboccipital approach:

Answer 18

probe is placed under base of skull and angled up into foramen

Question 19

Patient is laying on their right or left side w/ their back towards you for a suboccipital approach.

Answer 19

Left

head tucked in towards chest

Question 20

Transorbital approach:

Answer 20

carotid siphon and opthalamic artery
probe is directed toward the orb to locate the OA and then followed to the carotid siphon - distal to the intracranial ICA

Question 21

Transtemporal approach:

Answer 21

cephalad to zygomatic arch

immediately anterior and slightly superior to tragus of ear

Question 22

Patient is in a ________ position for a transtemporal approach

Answer 22

supine

Question 23

When we’re in the anterior orientation of the transtemporal approach, what do we visualize?

Answer 23

M1 and M2
C1 of carotid siphon
A1 of ACA and AComm

Question 24

When we’re in the posterior orientation of the transtemporal approach, what do we visualize?

Answer 24

P1 and P2 of PCa
top of basilar artery
Pcomm’s

Question 25

Suboccipital-transforaminal is essential screening what?

Answer 25

distal vertebral arteries (V4) and the basilar artery through its entire length

Question 26

Suboccipital-transforminal approach:

Answer 26

probe is placed between the posterior margin of the foramen magnum and the spinous process of C1 vertebra laying on side with head tucked into chest beam is aimed at bridge of nose

Question 27

What types of people pose a difficulty for scanning using the suboccipital transforminal approach?

Answer 27

the elderly

Question 28

What are some other approaches that can be used?

Answer 28

transorbital (can see OA and anterior circulation) submandibular (extracranial studies, probe is placed in retromandibular area, useful for carotid dissections and chronic ICA occlusion w/ collaterals)

Question 29

What are the typical insonation depths for the following vessels? (transtemporal approach--mm) MCA, ACA, carotid siphon, PCA and basilar

Answer 29

``` MCA- 50 ACA- 70 CS- 65 PCA- 65-70 B- 75 ```

Question 30

What are the typical velocities for the following vessels? (transtemporal approach--cm/s) MCA, ACA, carotid siphon, PCA and basilar

Answer 30

``` MCA- 55 ACA- 50 CS- 39 PCA- 40 B- 40 ```

Question 31

How do we identify cerebral arteries?

Answer 31

``` insonation depth direction of flow @ insonation depth flow velocity probe position (window) direction of US beam (ex. posterior, anterior) traceability of vessels ```

Question 32

What flow is seen in the cerebral arteries?

Answer 32

Low resistance flow spectrum similar to ICA flow

Question 33

How to start exam:

Answer 33

Start with the transtemporal approach Identify the midline of the brain If the midline is not visible,then the exam may be futile Once it is identified,turn on the color The MCA is identified on either side of the midline at a depth of 50-55 mm Track the ipsilateral arterial network,by angling he probe anteriorly toward the ACA and then posteriorly toward the PCA

Question 34

MCA and other arteries can be tracked from more shallow insonation depth ____mm to deeper sites _____mm

Answer 34

35-55

Question 35

Changes in what can indicate disease?

Answer 35

flow profile and direction

Question 36

When tracking the MCA medially (65-70mm depth),an abrupt change in flow direction-away from the probe-indicates insonation of A1 segment. Is this normal?

Answer 36

Yep