Extracranial Cerebrovascular Pathology Flashcards
Describe plaque of atherosclerotic disease
Location
Surface characteristics - smooth vs irregular
Echogenicity - homogeneous, heterogeneous, calcification
(low, moderate, strong)
describe atherosclerosis
thickening
hardening
loss of elasticity
name the 6 types/forms of plaque
plaque accumulations lipid complex carbohydrates fibrous tissue calcium fibrin
describe fatty streak plaque
thin layer of lipid material
homogeneous
low level echoes
describe fibrous plaque
homogeneous
low to medium echoes
accumulation of lipid and other
describe complicated lesion plaque
fibrous with collagen and debris
heterogeneous
bright echoes with shadow
describe ulcerative lesion plaque
deterioration of the surface
may result in embolization - breaking off
what plays a role in plaque
inflammation
plaque has a ______ matrix because lipids are ingested by ______
fibrous
macrophages
define plaque
echogenic material that encroaches on the arterial lumen
uncomplicated or stable plaque is ______
uniform
complicated plaque is _____ _____ and has _______
not uniform
ulcerations
what is embolism
piece of thrombus that moves until it lodges in a blood vessel
what is an aneurysm
abnormal localized dilatation - rare in the cervical carotid
what are 2 types of nonatherosclerotic disease
arteritis
Takayasu’s
what is Takayasu’s
chronic inflammation that results in narrowing of arteries
describe degree of stenosis
elevated velocity through the narrowed segment color changes post stenotic disturbances turbulent blood flow spectrul broadening
Important to differentiate a stenosis from an ______
occlusion
how do you rule out any trickle of flow
doppler color doppler power doppler decrease color PRF adjust sample volume
describe an ICA occlusion - secondary characteristics
echogenic material filling the lumen lack of arterial pulsations reversed blood flow loss of diastolic flow in CCA increase velocity in ECA increased velcity in contra ICA
describe a stenosis
increased velocity - peak systolic velocity, end diastolic velocity, systolic velocity ratio
what is the criteria for a stenosis
important
Stenosis chance PSV EDV
< 50% < 125 cm/sec n/a
50-79% >/= 125 cm/sec n/a
80-99% >/= 125 cm/sec >/= 140 cm/sec
describe a critical stenosis
pressure and flow volume descrease
what does a degree of abnormality depend on when dealing with a critical stenosis
length of narrowing diameter of narrowing pressure resistance collateral
describe the 3 things in a stenosis profile
prox to stenosis, flow is dampened and pulsatility increases
at the stenosis, increase velocities and spectral broadening
post stenotic, flow reversals, disturbed flow
stenosis:
_____ pitched sound
_____ velocities
_____ broadening
_____ to a stenosis - turbulent (dampeded/more round)
higher
higher
spectral
distal
the highest velocity obtained from and ICA stenosis is used to classify what
degree of narrowing
doppler signals obtained distal to the area of poststenotic flow disturbance may be _____ or _____, and the upstroke of the distal doppler spectral waveform may be _____
normal or diminished
slowed
stenosis usually happen where
distally
stenosis are _____ and systolic peak is _____
dampened
rounded
stenosis have a ______ ______ - delay arrival of systolic peak with low velocity
Tardus parvus
An ICA occlusion is not amenable to _______ intervention
surgical
To characterize an ICA as occluded, the artery should be evaluated with what
doppler, color doppler, and power doppler to rule out the presence of trickle flow
when determining if the ICA is occluded, the color PRF should be ______ to document the presence of any slow moving blood flow and the color gain should be ______ to enchance any blood flow that may be present
decreased
increased
how is a residual lumen/trickle flow seen sonographically
the “string sign” using power doppler
what surgery is done for plaque removal
thrombo endarterectomy
Flow compensation:
internalized ECA - indicates _______
high grade stenosis of ECA - _____ flow elevated
high grade stenosis of ICA - _____ demonstrates higher resistance flow
disease - CCA occlusion
ICA
CCA
turbulent flow is caused by what
stenosis
kinking
tortuosity
increase in vessel diameter
describe vertebral artery
branches of the subclavian arteries
asymmetrical
unite to form basilar artery
long CCA - angle posterolaterally toward the back of neck
wide variation in velocities
direction of flow
reversal of flow = subclavian steal –> obstruction in subclavian artery on same side
describe subclavian steal
reversed flow in vertebral artery
monophasic flow dampened
more often on left side
deceleration with late systolic velocities
describe subclavain artery
multiphasic high resistance doppler
blood pressure difference of greater than 20 mmHG is associated with disease in the side of the lower pressure
what needs to be interpreted with a carotid exam
location of stenosis extent of plaque patency of distal ICA presence of tortuosity characteristics of plaque
2 types of error interpretations
technique - positioning
equipment settings
Placement of sample volume must be _______ to the vessel wall
parallel
sample volume should be kept ______
small
sample volume in the ______ of the vessel
center
angle of _____ degrees or less must be used for doppler
60
describe 5 things about aneurysms
uncommon pulsatile neck masss bruit weakness of the media blood swirling
describe CCA aneurysms
tortuous
significant increase in vessel diameter
abn blood flow pattern
describe a dissection
blunt and penetrating trauma cervial injuries neck flexion associated with Marfan's syndrome between intima & medial layers creating a false lumen
dissections can be caused by ______
trauma
desribe dissection appearance
blood tears through the intima into the media
different flow in lumen
luminal narrowing
describe fibromuscular dysplasia (FMD)
non atherosclerotic unknown etiology affects the media of the arterial wall mid segment of the ICA bilateral in 65% usually in females
FMD gold standard is
angiography - “string of pearls”
turbulent flow and absence of plaque
what is the carotid body
small mass of vascular tissue that adjoins the carotid sinuses
ovoid - 1 mm in size
located in adventitia - posterior aspect of CCA bifurcation
component of autonomic nervous system
carotid body assists in regulating ______, ______, and ______
heart rate
blood pressure
respiration
describe carotid body tumors
rare
hypervascular structure that usually lies between the ICA and ECA
ECA branch supplies blood to the tumor
slow growing neoplasms
clinical symptoms of a carotid body tumor
palpable neck mass
headache
after a endarterectomy the ______ layer is missing because of removal
intima
_____ _____ _____ is a technique that has been introduced as an alternative to carotid endarterectomy in selected patients
carotid artery stenting
the gray scale image of a stent produces ______ echos
bright
review protocol…
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