Extracranial pathology Flashcards
Atherosclerotic disease: what do you need to evaluate?
location?
surface characteristics: smooth vs irregular??
echogenicty: homogeneous, heterogenous, calcification??
What is atherosclerosis?
thickening
hardening
loss of elasticity
WHat is plaque made of?
lipid complex carbohydrates
fibrous tissue
calcium
fibrin
it accumulates and causes the lumen to move
Where is the most common location for plaque?
typically in the bulb
What is a fatty streak of plaque?
thin layer of lipid material
homogeneous
low level echoes
what is fibrous plaque?
homogeneous
low to medium echoes
accumulation of lipid
what is a complicated lesion of plaque?
fibrous with collagen and debris
heterogeneous
bright echoes with shadow
what is an ulcerative lesion of plaque?
deterioration of the surface
may result in embolization
What causes a carotid artery stenosis?
accumulated plaque
Can a carotid have an aneurysm?
yes
walls should look like railroad tracks
rare but any artery can have an aneurysm
what is takayasu’s?
chronic inflammation that results in narrowing of arteries
arteritis - nonatherosclorotic
How do you determine the degree of stenosis?
elevated velocity through narrowed segment
color changes
post stenotic disturbances
turbulent blood flow
spectral broadening
How do you differentiate a stenosis from an occlusion?
rule out any trickle flow by using:
doppler
color doppler
power doppler
decrease color PRF
adjust sample volume
What are the secondary characteristics of an ICA occlusion?
echogenic material filling the lumen
lack of arterial pulsations
reveresed blood flow
loss of diastolic flow in the CCA
increase velocity in the ECA
increase velocity in the contralateral ICA
Where do you get the highest velocity?
at a stenosis
What is the stenosis criteria?
diameter PSV EDV
=. >=125cm/sec N/A
80-99% >=125cm/sec >= 140 cm/sec
What happens when there is a critical stenosis?
pressure and flow volume decrease cant get blood to brain
degree of abnormality depends on:
length of narrowing
diameter of narrowing
pressure
resistance
collateral
proximal to a stenosis flow is _______ and pulsatility _________
dampened
increases
At the stenosis _________velocities and spectral __________
increase
broadening
post stenotic flow ___________ and flow is _____________
reversed
disturbed
What sound does a stenosis produce?
higher pitched sound
also have:
higher velocities
spectral broadening
distal to a stenosis: turbulence
dampened more rounded see slide 171 for picture
how do you get rid of color alasing?
adjust the color scale
what is the highest velocity obtained from an ICA stenosis is used to classify what?
the degree of narrowing
What do the doppler signals obtained distal to the area of poststenotic flow disturbance look like?
may be normal or diminished
upstroke of the distal doppler spectral waveform may be slowed
What is tardus parvus?
delay arrival of systolic peak with low velocity
see slide 174 for picture
Is surgical intervention available for ICA occlusion?
no
if you aren’t seeing good color, how might you improve the image?
change the PRF (scale) or the color gain
What happens when you have an ICA occlusion on one side?
the other side changes velocity
What is the sign name for trickle flow?
string sign (may need to use power doppler)
What is the surgery called to remove a carotid stenosis?
thrombo endarterectomy
If the ECA starts to look like the ICA what usually has disease?
the CCA is usually occluded
if you have a high grade stenosis of ECA what happens to ICA
flow is elevated
what causes turbulent flow?
stenosis
kinking
tortuosity
increase in vessel diameter
what does the vertebral artery unite to form?
basilar artery
how do you see the vertebral artery?
angle back toward the spine
what kind of flow does a subclavian steal have?
monophasic flow damped
more often on the left side
reversed flow
What questions must you answer for stenosis evaluation?
location of stenosis
extent of plaque patency of distal ICA
presence of tortuosity
characteristics of plaque
What causes a dissection?
blunt and penetrating trauma
what is Marfan’s syndrome?
connective tissue disorder
genetic
can cause aortic enlargement
What is fibromuscular dysplasia (FMD)
non atherosclerotic
unknown etiology
affects the media of the arterial wall
mid segment of the ICA
bilateral in 65%
usually females
“string of pearls”
turbulent flow
absence of plaque
What is a carotid body?
small mass of vascular tissue that adjoins the carotid sinuses
ovoid structure 1 mm in size
located in the adventitia
component of the nervous system
what does the carotid body do?
assists in regulating heart rate, blood pressure, and respiration
chemoreceptor within the adventitial layer of the bifurcation
what is a carotid body tumor?
rare
palpable neck mass
headache
hypervascular
between ICA and RCA
Blood supply via ECA branches
slow growing neoplasm/mass
carotid body is ___________carotid body tumor is ___________
normal
abnormal
What are some common features of a carotid aneurysm?
uncommon
pulsatile neck mass
bruit
weakness of the media
blood swirling
tortuous CCA
significant increase in vessel diameter
abnormal blood flow pattern
What is the pathology of a dissection?
blunt and penetrating trauma
cervical injuries
neck flexion
associated with marfan’s syndrome
between the intima and medial layers creating a false lumen
What is a carotid endarterectomy?
the assessment of the carotid endarterectomy site by duplex imaging for technical adequacy is an effective method to improve the results of the operation
transducer is placed in a sterile sleeve and imaging is performed on the exposed artery
after endarterectomy the intima is missing because of removal
What is carotid artery stenting
technique that has been introduced as an alternative to carotid endarterectomy in selected patients
grayscale image of stent produces bright echoes
