2. Carotid ultrasound shows whether a waxy substance
called plaque has built up in your carotid arteries. The
buildup of plaque in the carotid arteries is called carotid
artery disease.
3. Carotid Atherosclerosis – Progession of
Dz
Plaque Formation
Plaque ulceration
Formation of Thrombus
Further Stenosis or
Occlusion
Release of Emboli
Plaque Enlargement
Decrease Cerebral Flow
Decreased or Absent Flow
4.
5. Over time, plaque can harden or rupture (break open).
Hardened plaque narrows the carotid arteries and reduces
the flow of oxygen-rich blood to the brain.
If the plaque ruptures, a blood clot can form on its surface. A
clot can mostly or completely block blood flow through a
carotid artery, which can cause a stroke.
A piece of plaque or a blood clot also can break away from
the wall of the carotid artery. The plaque or clot can travel
through the bloodstream and get stuck in one of the brain's
smaller arteries. This can block blood flow in the artery and
cause a stroke.
6. Who Needs Carotid Ultrasound?
1. Had a stroke or mini-stroke recently. During a mini-stroke, you may
have some or all of the symptoms of a stroke. However, the
symptoms usually go away on their own within 24 hours.
2. Have an abnormal sound called a carotid bruit in one of your
carotid arteries. Your doctor can hear a carotid bruit using a
stethoscope. A bruit might suggest a partial blockage in your carotid
artery, which could lead to a stroke.
3. Blood clots in one of your carotid arteries
4. A split between the layers of your carotid artery wall (dissection).
The split can weaken the wall or reduce blood flow to your brain.
7.
8. ULTRASOUND OF THE CAROTIDS - NORMALULTRASOUND OF THE CAROTIDS - NORMAL
Normal carotid bifurcation. Common carotid artery (CCA). Internal carotid
artery (ICA). External carotid artery (ECA)
10. The CCA is readily visible. Locate
it in transverse and rotate into
longitudinal.
The CCA will have a doppler trace that is
representative of both upstream and down stream
influences. Normal PSV for the CCA is usually less
than 100cms./sec
11. Assess the bifurcation in
transverse. Rotate on the ECA
origin to sample it longitudinally.
The ECA waveform is high resistance and may
have retrograde flow in diastole. A 'temporal-tap'
(TT) was employed here to confirm it was the ECA.
The normal range of PSV (peak systolic velocity)
for the ECA is from 77 cms./sec. to 115 cms./sec.
12. The ICA will have low resistance flow,
with constant forward flow during
diastole. The ICA origin incoporates
the bulb which may create a degree of
turbulent flow.
Normal Carotid bifurcation with the ICA
bulb and branch off the ECA.
13. Distal ICA scan plane. You may only
be able to see a few cm of the ICA if
there is a high bifurcation.
Unless the vessel is tortuous, you should
see a low resistance waveform with a clean
spectral window beneath the trace. The
normal PSV (Vmax in our image), ranges
from55 to 88 cms./sec. in the ICA
14. Transverse bifurcation scan plane.
These transverse images show the difference in
ICA-bulb vs ECA at the bifurcation and then
approximately 1cm further distal.
15. From the mid-distal CCA slide and
angle posteriorly to visualise the
cervical transverse processes and
the vertebral artery.
The vertebral arteries can be variable in
diameter. They should always demonstrate
antegrade flow (toward the brain) and be low
resistance similar to the ICA.
16. Calcific lesions of carotid arteries
These ultrasound images of a young, asymptomatic adult female patient
reveal multiple calcific plaques of the common carotid arteries of both sides.
The intimal plaques measure 1.5 to 4mm. in size. These sonographic images
are diagnostic of dystrophic calcification of the intima of the carotid arteries.
Such lesions are very unlikely to cause stroke or thromboembolic events and
are hence of little significance.
17. Intima-media thickness (IMT) of carotid artery
The carotid artery/ arteries consist of 3 layers- the intima (the inner most thin
layer of endothelium), the middle layer or media (formed by smooth muscles)
and the outermost layer- the adventitia (formed by loose connective tissue.
Normal common carotid artery thickness should be less than 0.9 mm.
18. This middle aged male patient had a recent
partial stroke affecting the left side of face
and left upper limb. The B-mode ultrasound
images of the right Common carotid artery
show an atheromatous plaque of the lower
third of the vessel. This plaque is non
calcific and shows no evidence of
ulceration. The Color Doppler images of the
common carotid artery show no significant
obstruction to blood flow in this artery.
Possibly, there might have been a small
embolic episode some time ago resulting in
cerebral ischemia on this side.
19. This plaque also shows ulceration of the
surface which further complicates the
situation increasing the possibility of
embolism. Color Doppler ultrasound image
above shows no significant obstruction (less
than 50 % stenosis) to the flow through this
area of the carotid artery.The color Doppler
and spectral Doppler ultrasound images show
and confirm the extent of ulceration of the
surface of the carotid plaque. The degree of
stenosis of the common carotid artery does
not appear to be significant.
20. Ultrasound and color Doppler images of the right Common carotid (CCA) and
ICA (internal carotid) arteries show increased peak systolic velocity in both
these vessels. However, no major pathology was seen on the right side. The
right ECA (external carotid artery) also showed similar changes .The left CCA
shows marked high resistance flow with absent diastolic flow and in fact there
is flow reversal during diastole. Clearly there is a major pathology on the left
side.
21. Ultrasound and color Doppler images of the right Common carotid (CCA) and
ICA (internal carotid) arteries show increased peak systolic velocity in both
these vessels. However, no major pathology was seen on the right side. The
right ECA (external carotid artery) also showed similar changes .The left CCA
shows marked high resistance flow with absent diastolic flow and in fact there
is flow reversal during diastole. Clearly there is a major pathology on the left
side.
