Cerebrovascular Duplex Imaging

Question 1

5 indications for cerebrovascular duplex imaging

Answer 1

1. evaluate patients with signs or symptoms
2. identify and localize disease in extracranial carotid system
3. document the progression of disease
4. plaque characteristics
5. other diseases - dissection, aneurysm, tumor

Question 2

3 limitations of cerebrovascular duplex imaging

Answer 2

1. size of neck, depth of vessels
2. shadowing due to plaque calcification
3. dressing, sutures, etc

Question 3

tapping on the temporal artery can result in oscillations in the ___

Answer 3

ECA

Question 4

appearance of wall thickening/minor plaque

Answer 4

hypoechoic low level echoes
“fatty streaking”

Question 5

minor plaque usually is located at ___

Answer 5

distal CCA, origin of the ICA

Question 6

moderate plaque usually is seen at the ___

Answer 6

proximal ICA with shadowing from calcification

Question 7

plaque characteristics

homogenous -
heterogenous -

Answer 7

homogenous - smooth fibrous lesion
heterogenous - irregular

Question 8

plaque characteristics

homogenous & heterogenous areas -
heterogenous with calcification -

Answer 8

homogenous & heterogenous areas - complicated lesion (smooth and irregular)
heterogenous with calcification - smooth and irregular, difficult to tell

Question 9

plaques are often ___ and measurement greatly depends upon ___

Answer 9

often asymmetrical
depends upon the plane of the US beam

Question 10

cerebrovascular duplex imaging

PSV
normal -
< 50% stenosis -
> 50% stenosis -
> 80% stenosis -

Answer 10

PSV

normal: <125 cm/sec
< 50% stenosis: <125cm/sec
> 50% stenosis: >125cm/sec
> 80% stenosis: >125 cm/sec

Question 11

cerebrovascular duplex imaging

EDV
normal -
< 50% stenosis -
> 50% stenosis -
> 80% stenosis -

Answer 11

EDV

normal: < 125cm/sec
< 50% stenosis: < 125cm/sec
> 50% stenosis: < 140cm/sec
> 80% stenosis: > 140cm/sec

Question 12

cerebrovascular duplex imaging

PSV > 125cm/sec =
EDV > 140cm/sec =

Answer 12

PSV > 125cm/sec = > 50% stenosis
EDV > 140cm/sec = > 80% stenosis

Question 13

cerebrovascular duplex disease

3 potential sources of error that cause over-estimation of disease

Answer 13

1. angle of insonation - tortuous vessels
2. increased cardiac output
3. compensatory flow

Question 14

6 potential sources of error that would cause underestimation of disease

Answer 14

1. angle of insonation
2. poor technique - miss the highest velocity jet
3. PSVs may be less than expected in very severe stenoses
4. altered cardiac output, severe LV dysfunction, critically ill patients, LVAD
5. stenosis in dilatation, prominent carotid blub
6. geometry of the stenosis/lumen

Question 15

vertebral artery courses along the spinal column through the ___

Answer 15

vertebral processes

Question 16

vertebral evaluation is an accurate indirect assessment of the ___

Answer 16

subclavian

Question 17

what is subclavian steal?

Answer 17

occlusion of the subclavian artery with flow traveling up one vertebral artery, down the contralateral artery via the basilar artery

Question 18

3 indications of subclavian steal

Answer 18

1. retrograde flow in vertebral artery
2. abnormal subclavian artery waveform
3. brachial BP difference of > 20mmHg

Question 19

subclavian artery stenosis is more common on the ___

Answer 19

left

Question 20

subclavian artery lesion is often ___

Answer 20

intrathoracic

Question 21

what is the North American Symptomatic Carotid Endarterectomy Trial (NASCET)?

Answer 21

important trial that determined the efficacy of intervention for carotid artery disease

sympathetic patients with >70% stenosis benefited from endarterectomy

Question 22

ICA/CCA ratio =

normal -

Answer 22

ICA/CCA ratio = PSV of ICA / PSV of distal CCA

normal < 2.0

Question 23

ICA/CCA ratio > 4.0

Answer 23

70% stenosis

Question 24

___ is typically considered the gold standard for carotid artery evaluation

Answer 24

angiography

Question 25

diameter reduction =

Answer 25

diameter reduction = [ 1 - (D1/D2) ] x 100

Question 26

what is endarterectomy?

Answer 26

surgical procedure in which the artery is isolated and opened to remove plaque

Question 27

post endarterectomy try to identify the ___

Answer 27

proximal and distal endpoints

Question 28

post endarterectomy recurrent disease 1. ____ most common 3-24months 2. ___ most common > 24 months

Answer 28

1. intimal hyperplasia (3-24 months) 2. recurrent atherosclerotic disease (>24 months)

Question 29

carotid artery post angioplasty check patency of ___ if the stent spans the origin

Answer 29

ECA

Question 30

4 intra-operative applications

Answer 30

1. assess adequacy of surgical technique 2. identify defects and/or platelet aggregation 3. evaluate hemodynamics 4. very detailed, high resolution images