Extracranial Cerebrovascular Evaluation Flashcards
(122 cards)
0
Q
spectrum analysis sorts out the _____ _____ - FFT
A
Doppler frequencies
1
Q
describe blood flow through spectrum analysis
A
pulsatile flow is slower at the periphery vessels are not straight vessels are not uniform distorted by pathology
2
Q
_____ _____ graphs the Doppler frequencies by moving blood
A
Doppler Spectrum
3
Q
Doppler angle of _____ degrees or less is required for accurate frequency and velocity information
A
60 degrees
4
Q
_____ _____ needs to be correctly positioned for Doppler Spectrum
A
sample volume
5
Q
examples of broad systolic peak and forward flow throughout distole
A
CCA, ICA, vertebral, renal, celiac
low peripheral resistance
entire waveform above or below baseline
6
Q
examples of tall, narrow sharp systolic peaks, reversed or absent flow through diastole
A
extremity arteries, ECA, SMA (fasting)
high peripheral resistance
7
Q
pulsatility varies depending on _____
A
location
8
Q
what alters pulsatility
A
physiology and pathology
9
Q
pulsatility shows status of _____ function
A
cardiac
10
Q
what is acceleration
A
flow velocity accelerates rapidly in systole
severe arterial obstruction, flow acceleration may be slowed
11
Q
the greater the energy difference (gradient) the ______ the flow
A
greater
12
Q
movement goes from _____ pressure to _____ pressure
A
high to low
13
Q
describe disturbed flow
A
less orderly widening of the waveform vascular disease normal tortuous vessels prominent area -- bulb
14
Q
arterial obstruction description
A
increased velocity disturbed flow post stenotic prox pulsatility changes distal pulsatility changes indirect effects - collateralization
15
Q
Poiseuille’s Law formula
A
Q = volume flow R = vessel radius - most important b/c its to the 4th power L = length of the vessel N = viscosity
16
Q
Poiseuille’s Law: the velocity of the steady flow of a fluid through a narrow tube varies ______ as the pressure and the 4th power of the radius of the tube and _____ as the length of the tube and the coefficient of viscosity
A
directly
inversely
17
Q
Poiseuille’s Law: volume flow is _____ to the 4th power of the radius, even small changes in radius can result in _____ changes in flow
A
proportional
large
18
Q
Poiseuille’s Law:
if pressure difference increases, flow rate _____
if diameter increases, flow rate _____
if length increases, flow rate _____
if viscosity increases, flow rate _____
A
increases
increases
decreases
decreases
19
Q
Bernoulli’s Priciple
stenotic segment - pressure decreases, velocity _____
prox to a stenosis - pressure ______
distal to a stenosis - pressure _____
A
increases
increases
increases
20
Q
flow moves along the path of least ______
A
resistance
21
Q
_____ _____ _____ is a hallmark of high resistance vascular beds
A
diastolic flow reversal
22
Q
_____ relationships are important as you evaluate arteries with US and Doppler
A
flow
23
Q
______ or ______ is a interruption of blood flow to the brain
A
ischemic stroke or brain attack - 80%
24
_____ _____ ruptured intracranial blood vessel
intracranial hemorrhage - 20%
25
_____ _____ _____ disease is responsible for more than 50% of all stroke
extracranial carotid artery disease
26
_____ are the 3rd leading cause of death in the USA
strokes
27
what is the reasoning for scanning the carotid
to detect potential causes of stroke
28
what is a stroke or CVA
PERMANENT ischemic deficit
29
what is TIA
Transient ischemic neurologic deficit
resolves in < 24 hrs (1-30 mins)
30
what is RIND
reversible ischemic neurologic deficit
resolves in > 24 hrs (up to 3 weeks)
31
brain depends on the vascular system so even _____ episodes of interrupted cerebral blow can cause symptoms and cellular death
short
32
_____ remains the best treatment for stroke
prevention - take care of yourself (exercise, diet, etc)
33
what is a thrombotic stroke
clot in artery in the brain
34
what is an embolic stroke
piece of a clot is carried to the brain
35
what is a hemorrhagic stroke
blood vessel in the brain breaks
36
non modifiable risk factors
age - risk increases
sex - higher in males
race - higher in african americans
previous stroke
37
modifiable or controllable risk factors
```
hypertension
atrial fibrillation
cardiac disease
diabetes mellitus
elevated cholesterol
smoking
sedentary lifestyle
obesity
```
38
warning signs of stroke
```
sudden numbness or weakness
sudden confusion, trouble speaking
sudden vision issues
sudden trouble walking, dizziness, or loss or balance
sudden headache
```
39
symptoms of a stroke
weakness/numbness of one side indicate disease on the contralateral carotid
ocular symptoms indicate disease on the same side - ipsilateral
40
signs of a stroke
smile
talk
raise both arms
stick out the tongue
41
asymptomatic symptoms of a stroke
risk factor
| bruit
42
symptoms of a stroke:
what is...
```
amaurosis fugax
hemiparesis
dysarthria
aphasia
dysphagia
ataxia
diplopia
vertigo
```
```
amaurosis fugax - transient vision loss
hemiparesis - paralysis
dysarthria - speech difficulty
aphasia - inability to communicate
dysphagia - difficulty swallowing
ataxia - gait disturbances
diplopia - double vision
vertigo - sensation of moving objects
```
43
aortic flow goes ----->
ascending aorta --> arch --> descending aorta
44
ascending aorta comes from _____
left ventricle
45
what are the 3 main arteries on the aortic arch
brachiocephalic or innominate artery
left CCA
left subclavian artery
46
the brachiocephalic artery divides into what 2 arteries
right CCA and right subclavian
47
brachiocephalic artery (right CCA & subclavian) gives rise to the right _____
right vertebral
48
left CCA originates to the left of the _____ artery
innominate or brachiocephalic
49
left CCA is usually _____ than the right CCA
longer
50
left subclavian artery gives rise to the _____
vertebral
51
aortic arch variants:
left CCA forming a _____ origin with the innominate artery
left vertebral artery arising from the _____
right subclavian artery arises from the arch _____ to the left
left innominate _____ ____
common
arch
distal
may exist
52
in the neck, the _____ artery, _____ vein, and _____ nerve are enclosed in connective tissue called a ______ _____
carotid artery
jugular vein
vagus nerve
carotid sheath
53
CCA is located _____ to the trachea and the thyroid gland
lateral
54
CCA is...
```
_____ in the neck
_____ to the jugular vein
_____ mm in diameter
_____ longer than right
connective tissue - ______ ______
______ ______ lies between the artery and vein
usually _____ branches
```
```
anterolaterally
medial
6-8
left
carotid sheath
vagus nerve
no
```
55
CCA terminates at the ______ of the ___ and ___
bifurcation of the ICA and ECA
56
Spectral analysis is performed by the _______ _____
computerized FFT
57
ECA originates at the ___ ____ ____, usually the _____ branch, and has a ____ resistance waveform
mid cervical level
smaller branch
high resistance
58
identifying characteristics of the ECA
```
smaller than ICA in diameter
usually anteriomedial vessel
has no bulb
cervical portion has branches
high resistance flow
responses to temporal percussion (tapping above ear lightly)
```
59
ECA has _____ branches
8
superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, superior temporal, internal maxillary
60
_____ _____ artery is the most commonly seen branch of the ECA
superior thyroid artery
61
____ ____ are used to signify ECA
temporal taps
62
ECA supplies blood to the ....
face, scalp, tongue, and neck
63
ECA runs _____ and _____ to the ICA
medially and anteriorly
64
ICA arises from the _____ _____
CCA bifurcation
65
ICA enters base of skull through the _____ ____
petrous bone
66
ICA is the _____ branch of the CCA terminal branches
larger
67
ICA supplies blood to the ...
brain, eyes, forehead, and part of the nose
68
ICA enter the cranial cavity via the _____ _____ in the temporal bone
carotid canal
69
ICA gives off ____ branches within the neck region
no
70
ICA bulb includes...
distal CCA and prox ECA and ICA
71
Cervical ICA usually does not have ______
branches
72
Area evaluated by Doppler may be tortuous, coiled, or kinked with ____ and ____
age and disease
73
ICA passing into the skull gives off the _______ artery at the carotid siphon
ophthalmic
*postero-laterally in the neck
74
ICA terminates at the _____ __ _____
circle of Willis
75
ICA distributes to the ____ resistance vascular bed
low
76
ICA vs ECA
ICA - lateral and posterior, no branches present in neck, low resistance waveform, no response to temporal tapping
ECA - medial and anterior, branches early in neck (superior thyroid artery), high resistance waveform, temporal tapping affects waveform
77
Carotid imaging procedure
gray scale
color
doppler
consistent doppler angle
78
4 things about duplex imaging
location of stenosis
extent of the plaque and patency of the distal ICA
presence of tortuosity or kinking of the vessels
plaque characteristics
79
doppler must be ______ to vessel walls
parallel
80
technical aspects of carotid imaging
```
high frequency linear transducer
color assignment
color scale - PRF
wall filter
color box
color gain
```
81
image the carotid in ____ ____ first before doing anything else
gray scale
82
how can the CCA be distinguished from the jugular vein
vein changes with respiration
| vein compresses
83
_____ and _____ scale (PRF) should be adjusted throughout the exam to evaluate the changing velocity patterns
color and velocity scale
84
make sure color and Doppler wall filter is set ____
low
85
The US transducer is moved from _____ following the CCA to the level of the _____ _____
cephalad
carotid bifurcation (thyroid cartilage)
86
at the bifurcation, the transducer is moved slightly ______ and _____ to image the origin of the ECA and ICA
anteriorly and posteriorly
87
doppler signals are recorded from the ____, _____, _____ CCA
evaluate all doppler signals ______
prox, mid, distal
bilaterally
88
ICA and ECA are individually followed distally to the angle of the _____
mandible
89
what degree should be used to doppler at vessel
60 degrees or less
90
using a _____ doppler angle permits comparison of repeated studies in the same individual
constant
91
CCA doppler signal will display a ______ doppler shift throughout cardiac cycle
positive
92
normal CCA carotid doppler appearance
sharp upstroke
clear doppler window
diastolic flow
93
____ ____ usually includes origin of ICA
carotid bulb
*dilation of prox vessel produces a change in blood flow characteristics
94
____ ____ ____ is a normal flow disturbance, is detected as a transient reversal of blood flow along posterior wall of the bulb
boundary layer separation
95
sample volume for ICA should start just _____ to this area
distal
96
ICA waveform shape is
smooth
97
ICA - _____ color, _____ waveform, ____ resistance
continuous
smooth
low
98
ECA demonstrates _______ pulsatile doppler signal because it supplies blood to skin and muscular bed of the scalp and face
more
99
ECA usually has a ________ slope to peak systole and blood flow velocity to ______ in late diastole
faster
zero
100
ECA - ______ pulsitile, ______ slope to peak, ______ resistance, color pattern ______ during diastole, ______ diameter, branch of the _______ ______ artery
```
more
faster
high
decreases
smaller
superior thyroid
```
101
vertebral artery is a branch of the ________ artery
subclavian
102
segments of the vertebral artery are...
extravertebral
intervertebral
horizontal
intracranial
103
___________ is evaluated during a carotid exam
extravertebral
104
the vertebral artery lies ______ than the CCA
deeper
105
how do you reliably identify the vertebral artery
it should be followed distally and periodic shadowing should be visualized from the transverse processes of the vertebrae
106
follow the vertebral artery as far _________ as possible
proximally
107
compare vertebral artery flow direction to CCA to confirm _______ or _______ flow
antegrade or retrograde
108
________ color velocity scale is helpful in locating the vertebral artery
decreasing
109
color flow pattern in vertebral artery will demonstrate ________ color throughout cardiac cycle, and the blood flow velocity is _______ resistive and ______ zero baseline throughout the cardiac cycle
continuous
low
above
110
medical history...
arm pressures - difference of > 20 mmHg suggests a stenosis or occulsion of subclavian artery on the side of lower pressure
presence of bruits
111
what is a subclavian steal
reversal of vertebral artery blood flow direction secondary to a significant obstruction prox to the origin of the vertebral artery in the ipsilateral subclavian or innominate artery
112
do all stenosis in carotid arteries cause bruits
no
113
gold standard method for ICA and ECA examination is ________ or ________
arteriography or magnetic resonance angiography
114
technical errors when doing a carotid scan
```
frequency too high for depth
inaccurate focal zone
incorrect angle
color gain too low
color scale too high
```
115
what is evaluated during a carotid scan
peak systolic velocity
end diastolic velocity
direction of blood flow
shape of doppler spectral waveforms
116
what is the most reliable way to distinguish the ICA from the ECA
doppler signal
117
features of ICA and ECA
```
size
branches
orientation
doppler
temporal tap
pulsatility
diastolic
dicrotic notch
```
ECA ICA
size smaller larger
branches yes no
orientation anterior posterior
doppler high res low res
temporal tap yes no
pulsatility flickers constant
diastolic low high
dicrotic notch clear unclear
118
what is systolic velocity ratio (SVR)
ICA / CCA
119
as stenosis develops _______ becomes elevated
PSV
120
______ is a good marker for high grade stenosis
EDV
121
what is bruit
noise caused by tissue vibration that is produced by turbulance
may be identified from normal artery or the bruit may be transmitted (cardiac)
