Week 5 Abnormal carotid / vertebral Scanning Flashcards
Waveform?
triphasic
*3 components of the cardiac cycle (peak systole, early diastole, & end diastole)
waveform?
turbulent
waveform?
biphasic
- End diastolic component missing
- Only the peak systolic & early diastolic components are present
waveform?
monophasic
- Early diastolic & end diastolic components missing
- Does not cross the baseline
waveform ?
laminar
waveform?
disturbed
what is Carotid bruit?
abnormal sound(s) heard by placing a stethoscope over a vessel
cause of bruit
- skin/tissue/vessel wall vibration
- diseased, tortuous vessels, or cardiac in origin
most common cause of stenosis
atherosclerosis
_____ disease changes the strength of signal
proximal
PROXIMAL TO THE STENOS
Proximal to an occlusion or high-grade stenosis, the _____ will increase
resistance
PROXIMAL TO THE STENOS In any antegrade diastolic flow proximal to stenosis, if it is present, it may be reduced or absent.
T or F ?
T
PROXIMAL TO THE STENOS
Proximal to stenosis pulsatility _______
pulsatility decreases
lower pulsatility due to increased resistance
AT THE STENOSIS
______ velocities compared to pre stenotic segment
_______ flow
Elevated
Laminar
BEYOND THE STENOSIS *Post stenotic ______ flow (right after the stenosis, not distal to stenosis) ____ broadening ____ of well define spectral edge
- turbulence or disturbed
- Spectral
- Loss
4 characteristics of distal stenotic flow:
- tardus parvus flow 2. prolonged systolic acceleration time 3. low pulsatility 4. dropped velocity
!!!
DISTAL TO THE STENOSIS characteristics
- Downstream ______ waveform
- prolonged _______
- Diminished _______
- Velocity should _____ distal to stenosis
- tardus-parvus *note: Tardus: Slow & late, Parvus: Small & little
- Systolic acceleration time
- pulsatility
- drop off
DISTAL TO THE STENOSIS
- Downstream tardus-parvus waveform
- Systolic acceleration time prolonged
- Acceleration time prolonged
- Diminished pulsatility
- Velocity should drop off distal to stenosis
EXCEPT: _______________
long stenosis, near occlusive lesions
FLOW WITH PRESENCE OF STENOSIS
site of stenosis?
proximal
FLOW WITH PRESENCE OF STENOSIS
site of stenosis?
mid
At stenotic lesion
*Note that monophasic, laminar flow
FLOW WITH PRESENCE OF STENOSIS
site of stenosis?
distal
waveform very distal to stenosis
Tardus Parvus
INTERPRETATION/GRADING STENOSIS
Currently the only published standards are for categorizing _______
ICA narrowing
*No published standards to quantify CCA or ECA stenosis (can qualitate them)
INTERPRETATION(ICA): degree of stenosis
ICA PSV >125 cm/s
(in %)
>50%
*125 cm/s is a key number
INTERPRETATION(ICA): degree of stenosis
ICA PSV >230 cm/s
ICA EDV >100 cm/s
≥70 but less than near occlusion
INTERPRETATION(ICA): degree of stenosis
If spectral waveforms are normal velocities, but plaque present, according to the criteria by SRU (chart on previous side), it gets reported as ______
<50%
INTERPRETATION ICA by visual
<15% stenosis by diameter
mild
INTERPRETATION ICA by visual
>80% stenosis by diameter
severe
INTERPRETATION ICA by visual
15-50% stenosis by diameter
moderate
NTERPRETATION ICA by visual
50-80% stenosis by diameter
moderately severe
INTERPRETATION(ICA): degree of stenosis
ICA EDV >140 cm/s
>80% *condition is more severe when EDV increases
INTERPRETATION(ICA): degree of stenosis
ICA EDV >140 cm/s
>80% *condition is more severe when EDV increases
INTERPRETATION(ICA) by waveform
<50% diameter diagnosis
INTERPRETATION(ICA) by waveform
50-74% stenosis
INTERPRETATION(ICA) by waveform
>75% diameter stenosis
3 parameters to assess stenosis
PSV
EDV
ICA/CCA ratio
_____ is useful in lower classes of stenois but it must/should be used in conjunction with EDV for higher grades of stenosis
PSV
As narrowing increases, _____ increases because resistance distally is decreasing allowing for flow to come
EDV
ICA/CCA ratio < ___ is considered within the normal range.
It is an estimate of at least less than 50% stenosis which can be described as no hemodynamically significant stenosis.
2.0
ICA/CCA ratio
comparing the mid CCA PSV to the PSV of the ICA
The peak systolic velocity of the ICA and the peak systolic velocity of the CCA and divide them
*ICA PSV / mid CCA PSV = ICA/CCA ratio; value <2.0 considered normal
!!!ICA/CCA ratio of ____ = an approximate 60% stenosis (according to SRU guidelines)
3
OBSERVATIONS: CCA
- Has mixed ______
- ____ demonstrates higher velocities due to proximity to the arch
- Distal decreases due to the ___________
- *Recommended to use the ______sample area for ICA/CCA ratio calculation
- resistance
- Proximal
- widening of the bulb area
- mid CCA PSV
OBSERVATIONS: ICA
- Most common site of stenosis is @______
- Distal ICA _____ in velocity
- the take off
- increases
What is SUBCLAVIAN STEAL SYNDROME?
Stenosis or occlusion of the subclavian artery proximal to the takeoff of the vertebral artery
-Severe narrowing of the proximal subclavian artery results in a collateral pathway that ‘steals’ blood from the brain to supply the arm
*shows on the Doppler - retrograde waveform of vertebral artery
!!!
SUBCLAVIAN STEAL SYNDROME
Blood will flow down the vertebral coming from the _______ side rather than cross the stenosis and flow upward
contralateral
SUBCLAVIAN STEAL SYNDROME
- More common on the ____ side
- Most commonly caused by _____
- left
- atherosclerosis
!!!
SUBCLAVIAN STEAL SYNDROME: evaluation approach
- Must determine the direction of both vertebral arteries
- Early onset of subclavian stenosis may not result in a full reversal of flow, but rather a to-and-fro flow pattern
- If retrograde vertebral flow is seen- always check the ____ for increased velocities
- May also check bilateral blood pressure _____ mmHG difference from side to side
- Treatment: bypass graft from the ____ to the ____
- subclavian
- >15-20
- carotid, subclavian
*Note: to-and-fro flow - a continuous or regular movement backward and forward; an alternating movement, flux, flow, etc.
!!!
What does this waveform present?
mild to moderate stenosis To-and-fro flow pattern: left vertebral artery side of subclavian stenosis- incomplete steal
What does this waveform present?
Retrograde flow within the left vertebral artery (side of subclavian stenosis)- complete steal
Which part of the artery is affected by fibromuscular dysplasia?
tunica media
What is FIBROMUSCULAR DYSPLASIA?
The medial layer (tunica media) of the arterial vessel develops hyperplasia, from increased collagen, and results in a lengthened narrowing- or narrowing that extends for a length of a vessel
FIBROMUSCULAR DYSPLASIA
- May see ___ sign/____ appearance
- Predominance in _____
- Common within the ____, bilaterally
- Results in ______ velocities
- string, beaded
- females
- distal ICA
- increased
What does the Doppler image present?
Color Doppler: swirling of the color within the aneurysm/out pouching PW Doppler: to-and-fro waveform
CAROTID ANEURYSM
- Widening, dilatation, ballooning of the vessel (___ times larger than its original size)
- Caused when portion of the vessel wall weakens
- Caused by ____ or _____
1.5, trauma, infection
DISSECTION
- _____ lining elevation resulting in flow appearing as a double lumen
- Can be fatal, causing ____ or ______
- Can be caused by ____, _____, or unknown
- Intimal
- stroke, asymptomatic
- trauma, genetic
Carotid Body Tumor
_______ is a tumor that develops between the ICA and ECA
Paraganglioma
*Note: Paraganglioma is a type of neuroendocrine tumor that forms near certain blood vessels and nerves outside of the adrenal glands.
Carotid Body Tumor
2 characteristics of paraganglioma:
- low malignancy (potential)
- highly vascular
*can become large and compress on adjacent vessels
Management of Carotid Disease
2 modalities:
MRI
arteriography
Treatment of Carotid Disease
name 2:
endarterectomy: surgical removal of part of the inner lining of an artery, together with any obstructive deposits, most often carried out on the carotid artery or on vessels supplying the legs
senting
