This document provides an overview of performing a normal carotid artery Doppler study. It discusses the anatomy of the carotid arteries and examines protocol, including using high-frequency transducers, color Doppler, and analyzing Doppler spectral waveforms. The appearance of normal carotid artery walls and blood flow characteristics are described. Tips are provided for differentiating the external and internal carotid arteries. The document references sources for further information on vascular ultrasonography techniques and carotid artery anatomy.

1. Normal Carotid
Artery Doppler
Study
Dr. ABDULJELIL, R1

2. OUTLINE
ü Carotid Artery Anatomy
ü Examination protocol and Instrumentation
ü Ultrasound Appearance of the Normal Carotid
Artery Walls
ü Normal Blood Flow Characteristics
ü Tips for Differentiating the ECA from ICA
2

3. Carotid Artery Anatomy
The brain is supplied
directly by four
vessels

5. ICA and ECA

6. • ECA normally supply no blood to the brain. However,
several of their branches can become important
collateral pathways if occlusion occurs in the internal
carotid or vertebral arteries.

11. LATERALCRANIALPROJECTION

12. Anomalous Arch formations
• most commonly involving the origins of the
carotid and vertebral arteries

14. Examination protocol and Instrumentation
•
1. high-frequency (5 MHz or above)
transducers
2.color Doppler imaging
3.Duplex ultrasound with angle
correction capabilities
4.Doppler spectral waveform
analysis

16. ü Harmonic imaging is recommended to improve resolution and reduce
artifacts
ü Power Doppler imaging is recommended to assess low flow states and
possible occlusions
ü Doppler angle 60 degree or less by using angle correction setting(AC)
ü Sample volume is squarely within the center of the vessel~1/3 of vessel
diameter

17. Starting Carotid Ultrasonography: Patient
Position
ü Two option:
1. overhead position:-
The beneft of this position is that
the examiner can use both
hands and there are plenty of
positions possible for the US
probe.
The examiner should be familiar
with using both hands, which
requires some practice.

18. 2. lateral sitting position:-
which is used for most other ultrasonography
examinations.
This position makes it easy to control the machines
However, the right posterior projection is a bit more
diffcult.
Between these two choices, the overhead
position for Doppler ultrasonography of the
carotid artery is recommended.

19. ü A pillow is not necessary. In fact, it produces a
poorer window for the carotid artery.
ü The optimal patient head position is tilted about
45° away from the artery being examined.
ü The neck of the patients should be relaxed.
Contractions of the sternocleidomastoid muscle
cause poor sonic penetration and make
positioning of the probes diffcult.

20. •Transducer Position
ü long-axis (longitudinal) planes:
vGenerally,the posterolateral and far-posterolateral
positions are most useful for showing the carotid
bifurcation and the ICA, but,in some cases, an
anterolateral approach works best (very thick necks).
• far posterolateral approach often provides the best
images of the distal ICA. To use this view effectively, it
is necessary to turn the patient’s head far to the
contralateral side and to place the transducer
posterior to the sternocleidomastoid muscle
ü short-axis (transverse) views: anterior, lateral, or
posterolateral approach

22. Ultrasound Appearance of the Normal Carotid
Artery Walls
Three layers:
Intima
ü endothelial lining of the artery.
Media
ü connective tissue…. CCA
ü smooth muscle cells…ICA
Adventitia
ü connective tissue

23. • optimal gray-scale image of the longitudinal scan of the
carotid artery shows two bright interfaces along the
artery wal

24. intima-medial thickness (IMT)
• distance between the upper and lower bright line
• has been widely used as one of the parameters of
atherosclerosis
• is generally measured on the distal CCA at the far wall
because:-
1. the CCA is easier to image and less variable than the
ICA due to the angle of the beam or depth of the vessel
2. Focal atherosclerotic lesions are much more common in
the ICA than in the CCA
<1mm -normal
1-2mm-initial atherosclerotic lesion
>=2mm-sign of mild plaque

25. Normal Blood Flow Characteristics:

26. Abnormal Flow

28. normal flow reversal zone

29. spectral arterial wave

30. ü mean peak systolic velocity in the ECA is 77 cm/sec to 115 cm/sec

31. ü ICA Peak systolic velocities is up to 100 cm/sec

32. ü CCA peak systolic velocity obtained 2 to 4 cm below bulb
ü Show moderately broad systolic peaks
ü moderate amount of blood flow throughout diastole

33. Tips for Differentiating the ECA from ICA

37. References
• Introduction to Vascular Ultrasonography,6th edition
• Peripheral Vascular Ultrasound HOW, WHY AND
WHEN,2nd edition
• General principles of carotid Doppler
ultrasonography:REVIEW ARTICLE
• NETTER ATLAS OF HUMAN ANATOMY, 7th edition

38. THANK YOU