Transcranial Doppler and Misc Cerebrovascular Flashcards Preview

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Flashcards in Transcranial Doppler and Misc Cerebrovascular Deck (28)
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1

What is capable of evaluating onset, severity, and time course of vasoconstriction from subarachnoid hemorrhage?

transcranial Doppler

2

Transcranial Doppler is capable of assessing what?

Intracranial arteriovenous malformations
Assess patients with suspected brain death
Intracranial stenosis, occlusions, and assess collateral circulation

3

Limitations of transcranial Doppler?

- Recent eye surgery
-Adequate penetration of temporal bone from hyperostosis
-Inaccurate vessel identification with nonimaging technique

4

What are three acoustic windows used for transcranial doppler?

transtemporal, transorbital, and transforaminal/suboccipital

5

What is required for accurate vessel identification with transcranial doppler?

- Depth of sample volume
-Velocity of blood flow
-Direction of blood flow
-Relationship of flow patterns to one another

6

2 MHz pulsed Doppler, zero angle of insonation is assumed, and time average max velocity (TAMV) or mean velocity are used in what?

transcranial doppler

7

The unilateral transtemporal approach if used for what vessels?

MCA, ACA, PCA, and terminal ICA

8

Ipsilateral transorbital approach to evaluate what arteries?

ophthalmic artery and carotid siphon

9

The intracranial vertebral and basilar arteries are evaluated with what approach?

transforminal/ suboccipital approach

10

What is the cross-over collateral pathway?
transcranial

Antegrade flow in anterior cerebral artery from contralateral ACA via anterior communicating artery

11

What is the external to internal collateral pathway?
transcranial

retrograde flow in opththalmic artery

12

What is the posterior to anterior collateral pathway?
transcranial

increased flow in posterior cerebral artery (PCA), reversing direction of flow in the PCom artery

13

Factors that may alter intracranial blood flow?

age, sex, hematocrit, blood gases, metabolism

14

Vasospasm transcranial?

-Most accurate in MCA
-Serial recordings necessary
-Mean velocities >120 cm/s
Severe vasospasm = >200cm/s

15

Indication of arteriovenous malformation in transcranial doppler?

- Increased systolic and diastolic flow velocities
- Very low pulsatility indices
- Reduced flow in adjacent arteries

16

Subclavian occlusion results in retrograde flow in what artery?

ipsilateral vertebral

17

What is a recommended treatment for subclavian steal?

bypass graft or endarerectomy

18

Indications of subclavian steal?

- BP difference of 15-20 mmHg
- Decreased pulses in affected arm
- Ipsilateral vertebral artery feeding high-resistance vascular bed
- Patient usually asymptomatic, arm claudication is rare

19

Inflammation of the arterial wall of the superficial temporal artery or its frontal and/or parietal branches?

temporal arteritis

20

Characteristics of temporal arteritis?

- Inflammed arterial segments usually larger in diameter with homogeneous thickening evident on B-mode
- An anechoic halo from edema of the intima may be seen
- Intimal thickening may result in hemodynamically significant stenosis where PSV's are doubled

21

An arteriography can be usesd to detect abnormalities such as?

filling defect, absent vessel, aberrant anatomy

22

Equation for calculating diameter reduction longitudinally?

DR=(1-d/D) x 100

23

Equation used to calculate diameter reduction in trans?

a=d^2

24

What test is extremely sensitive in detecting the presence of stenosis but tends to overestimate the disease process?

MR angiography

25

What test is most frequently used to evaluate cerebrovascular disease?

CT

26

For a stenosis what surgical treatment is done to remove atherosclerotic material?

endarerectomy

27

When there is an occlusion, what surgical intervention is done?

usually none

28

What is designed to maintain the intraluminal structure and patency of the artery and acts as a type of scaffold?

a stent
may expect some flow acceleration post-stenting