ULTRASOUND EVALUATION OF CAROTID DISEASES

1. CAROTID DOPPLER STUDY
Dr.I.Gurubharath MD PhD Dr.Pooja MD

2. Doppler US Carotid arteries
• Anatomy of Carotid arteries
• Normal Doppler US of carotid arteries
• Causes of Carotid artery disease
• Effect Extra carotid arteries

3. CAROTID ARTERY ANATOMY
• The right and left CCAs ascend into the neck
posterolateral to the thyroid gland and lie deep to the
jugular vein and sternocleidomastoid muscle.
• The CCAs have different proximal configurations, with
the right originating at the bifurcation of the innominate
(brachiocephalic) artery into the common carotid and
subclavian arteries.
• The left CCA usually originates directly from the aortic
arch but often arises with the brachiocephalic trunk.
This is known as a “bovine arch” configuration.
• The CCA usually has no branches in its cervical region.

4. • Occasionally, however, it may give off the superior
thyroid artery, vertebral artery, ascending pharyngeal
artery, and occipital or inferior thyroid artery.
• At the carotid bifurcation, the CCA divides into the
external carotid artery (ECA) and the internal carotid
artery (ICA).
• The ICA usually has no branching vessels in the neck.
• The ECA, which supplies the facial musculature, has
multiple branches in the neck.
• The ICA may demonstrate an ampullary region of mild
dilation just beyond its origin.

7. Variants resulting due to elongation of ICA

8. Patient Position
One is the overhead position, in which the examiner sits beyond the
patient’s head beside the end of the examination table and use two
hands for ultrasonography. Head hyperextended and 45* away from side
being examined. High frequency linear tranducers

9. Transducer
• Higher-frequency linear transducers (>7 MHz) are
ideal for assessment of the intima-media
thickness and plaque morphology
• Lower frequency linear transducers (<7 MHz) are
preferred for Doppler examination.
• In a short muscular neck, if imaging with a linear
transducer is impossible, a curved-array
transducer (7 MHz)

10. All carotids artery examinesd should be performed with:
• Grey scale US
• Color Doppler
• Power Doppler
• Spectral doppler
• Vessels should be imaged as completely as possible
• Caudal angulation of the transducer in the
supraclavicular region and cephalic angulation at the
level of the mandible

11. Limitations
 Short muscular neck
 A high carotid bifurcation
 Tortuous vessels
 Calcified shadowing plaques

12. Avoid excess pressure on carotid bifurcation to avoid
-Stimulate carotid sinus
Bradycardia
Syncope
Ventricular systole
-Compress carotid arteries high velocities

13. Optimal Scanning Techniques and Doppler
Settings
• Scan both in transverse and longitudinal plane.
• Starting from proximal most CCA, bulb, ECA and ICA
• Distal carotid ‐2 cm from the bulb

14. Color Doppler Sampling Window
•Also known as the color box
•The size is adjusted to include all regions of interest.
•Adjustment of the angle‐by changing the box angles fro
m left to center or right
•Angling the transducer to ensure that the Doppler angl
e is less than 60°to the direction of blood flow

16. Proper steering

17. Sample Volume Gate and Angle Correction
• If the Doppler angle is small or more than 60 degree
small error in the estimated velocity.
• Preferred angle of incidence is 45°±4.
• The optimal position of the sample volume gate in a
normal artery is in the mid lumen parallel to the vessel
wall in a diseased vessel, parallel to the direction of
blood flow
• Should not be placed on the sharp curves of a tortuo-
us artery falsely high velocity reading
• Should not be placed too close to the vessel wall‐spec
tral broadening.

19. Spectral Broadening
•Spectral broadening results from turbulence in the bloo
d flow.
Spurious spectral broadening
•A large Doppler angle
•A sample volume gate located close to the vessel wall
•A high Doppler gain setting
•The size of the gate is normally ‐between 2 and 3 mm.
•Too small (1.5 mm) ‐the Doppler signal may be missed
•Too large >3.5 ‐spectral broadening

20. Color velocity scale
•If set belowthe mean velocity of blood flow, aliasing
throughout the vessel lumen
•set significantly higher than the mean velocity of b
lood flow, aliasing may disappear resulting in a mi
ssed stenosis
•In a normal carotid US examination, the color velo
city scale should be set between 30 and 40 cm/sec
(mean velocity).

22. Color Gain Control
•The color gain should be set so that color just reaches
the intimal surface of the vessel.
•If the color gain setting is too low, trickle flow may go
undetected.
•If a color gain setting is high, “bleeding” of the color
into the wall and surrounding tissues limit visualizatio
n of the plaque surface

24. Color Gain Control
•The color gain should be set so that color just reaches
the intimal surface of the vessel.
•If the color gain setting is too low, trickle flow may go
undetected.
•If a color gain setting is high, “bleeding” of the color in
to the wall and surrounding tissues limit visualization o
f the plaque surface

26. Role of power doppler
PDI may provide increased sensitivity to visualize the continuity of blood
flow in arterial stenoses

27. Advantages of power doppler
•Angle independent
•No aliasing
•Very sensitive to low velocity and low amplitude flow
•Helps in differentiating critical stenosis from occlusion
Disadvantages:
Motion sensitive
Does not give direction and velocity of flow

28. Technique and
Waveform Analysis
Normal Carotid Artery

30. CCA
• Begin proximally in transverse and follow distally to
the bifurcation.
• Assess the course (i.e. if tortuous) and the presence
of any intimal thickening or plaque.
• Repeat in longitudinal plane.
• Use colour to assess patency of vessel and the
direction of flow.
• Use 'Heel/Toe' technique to optimize insonation of
vessel, apply colour box and Doppler sample gate
with appropriate steering and angle correction.
• Measure the Peak Systolic (PSV) and end diastolic
velocities (EDV).

32. CCA
• Combination of ICA and ECA patterns,
• Intermediate amount of continuous forward diastolic
flow
• A sharp systolic upstroke and thin spectral envelope
flow below the baseline or filling in of the spectral
window normally should not be seen

33. BIFURCATION
• Assess in transverse and longitudinal for pathology.
• Identify the origins of the ICA and ECA arteries.
• Measure the Peak Systolic (PSV) and end diastolic
velocities (EDV) of the ECA.

38. • A low‐resistance waveform pattern
• Systolic peak should be sharp and the spectral en
velope thin continuous forward diastolic flow
• The systolic peak may be slightly blunter than the
systolic peak of the ECA
ICA

41. ECA
• The systolic upstroke is sharp
• The spectral envelope is thin.
• Reduced to no diastolic flow
• Diastolic flow should be symmetrical bilaterally
transient reversal in early diastole (characteristic ear
ly diastolic notch ) ‐a normal finding

42. Temporal tap maneuver

43. Temporal tapping of ECA
“Saw-tooth” appearnce

44. Normal flow reversal in ICA
Velocity is highest near the
flow divider
Flow reversal on opposite side
to flow divider
Flow reversal zone
Opposite to the origin of
ECA

45. VERTEBRAL ARTERIES
Return to a longitudinal plane of the CCA and angle the
beam postero-laterally to visualise the vertebral artery.
Ensure suitable PRF and gain for these smaller, deeper
vessels.
The flow should be low resistance flow ( presence of
forward diastolic flow).
Confirm the flow is antegrade i.e. towards the head -
(normal) or retrograde (suggesting subclavian steal
syndrome).

47. VERTEBRAL ARTERY
• Low resistance wave pattern
• forward diastolic flow
• no systolic or diastolic notch
• similar to carotid in flow (colour)
• No reversal of wave form

48. SCA

49. Intima –Media complex
Normal <0.8mm

50. Look At
•Pattern
•Systolic contour
•Diastolic pattern
•PSV
•DV
•ICA PSVs / CCA PSVs ratio
•Compare Right and Left side

52. Causes for unilateral low PSVs
• Proximal stenosis (brachiocephalic)
• Parvus tardus waveform or normal pattern but
asymmetrical PSVs.
• Distal stenosis (carotid bulb level)
• High resistance wave form

55. Indications for Carotid Ultrasound
• Evaluation of patients with hemispheric neurologic
symptoms, including stroke, transient ischemic attack,
and amaurosis fugax
• Evaluation of patients with a carotid bruit
• Evaluation of pulsatile neck masses
• Evaluation of patients scheduled for major
cardiovascular surgical procedures
• Evaluation of nonhemispheric or unexplained neurologic
symptoms Follow-up of patients with proven carotid
disease Evaluation of patients after carotid
revascularization, including stenting Intraoperative
monitoring of vascular surgery
• Evaluation of suspected subclavian steal syndrome
• Evaluation of a potential source of retinal emboli
• Follow-up of carotid dissection
• Follow-up of radiation therapy to the neck in select
patients

56. Causes of carotid artery diseases
Arteriosclerotic disease
NonArteriosclerotic disease
Fibromuscular dysplasia
Dissection
Vasospasm
Aneurysm and pseudoaneurysm
A-V Fistula
Arteritis
Carotid body tumor

57. Common sites for extracranial arterial disease
Most common site at carotid bifurcation with plaque extending
into ICA

58. Carotid plaque
•Defined as a localized protrusion from the wall into the
lumen with an area 50% greater than the intima media
thickness of neighboring sites.
Parameters and properties of plaques
(a) Plaque extent , Location ,size including the maximally
thick area and the elevated area
(b) Texture, Surface morphology
(c) Internal properties,
(d) Mobility.
(e) Luminal stenosis.

59. Homogeneous (stable)
plaque
Homogeneous
uniform echo pattern
with smooth surface
(acoustic impedance
similar to blood)
Heterogeneous
(unstable) plaque
Mixture of high,
medium, and low-level
echoes with smooth /
irregular surface;
Texture of Carotid Plaque

60. Ultrasound Types of Plaque Morphology
Type 1: Predominantly echolucent, with a thin
echogenic cap
(A) Sagittal and (B) transverse images show plaque (arrows) virtually
completely sonolucent, consistent with heterogeneous plaque (type 1). Note
smooth plaque surface

61. Type 2: Substantially echolucent with small areas of echogenicity (>50%
sonolucent)

62. Type 3: Predominantly echogenic with small areas of echolucency (<50%
sonolucent)

63. Type 4: Uniformly echogenic

64. Plaque types 1 and 2
• Intraplaque hemorrhage and ulceration, Unstable
• Abrupt increases in plaque size after hemorrhage or
embolization.
• Symptomatic patients with stenoses greater than
70% of diameter.
Plaque types 3 and 4
• Fibrous tissue and calcification.
• Homogeneous plaque.
• Benign,
• Stable plaques
• Asymptomatic individuals

65. Surface Characteristics of Carotid Plaque
US unreliable due to poor visualization of intima
4 Categories:
• Smooth
• Mildly irregular
• Markedly irregular
• Ulcerated

66. Intimal thickening
wavy / irregular line paralleling vessel wall
extending > 1 mm into vessel lumen
Early I-M hyperplasia with loss
of the hypoechoic component of
the I-M complex and thickening
(arrows

68. Plaque ulceration
Ultrasound Features Suggestive of Plaque Ulceration
• Focal depression or break in plaque surface
• Anechoic region within plaque extending to vessel
lumen
• Eddies of color within plaque

70. Plaque Ulceration and Abnormal Flow. (A) Longitudinal image of the proximal right internal
carotid artery (ICA) demonstrates heterogeneous plaque with an associated area of reversed
low-velocity eddy flow within an ulcer (arrow).
(B) Pulsed Doppler waveforms in this ulcer crater demonstrate the extremely dampened low-
velocity reversed flow, not characteristic of that seen within the main vessel lumen of the
ICA. A

71. Gray-Scale Evaluation of Stenosis
Measurements of carotid diameter and area stenosis should be made in the
transverse plane, perpendicular to the long axis of the vessel, using gray-
scale, B-flow, or power Doppler sonographic imaging
(A) Power Doppler transverse image shows a less than 50% diameter
stenosis (cursors). (B) Transverse B-mode flow image of the right carotid
bifurcation shows measurement of stenosis (B) in area of internal carotid
artery (ICA). A, Outer ICA area.

72. Circumferential calcified plaque in the proximal ICA.
(a) PW Doppler image of the right ICA obtained immediately distal to a circumferential
shadowing plaque shows no sign of turbulence, and the PSV is within normal limits.
Therefore, there is unlikely to be a significant stenosis behind the calcified plaque.
(b) PW Doppler image of the proximal right ICA shows a tardus-parvus waveform. A
severe proximal stenosis behind the shadowing plaque is suspected; therefore, evaluation
with another imaging modality is required.

73. Abnormal CCA
Either low or high psvs.
Abnormally high‐resistance waveform,
An abnormally low‐resistance waveform,

74. Abnormally low PSVs
A normal CCA PSV should be in the range of approxi
mately 60 –100 Cm/s
•IF less than this, examine opposite side
Symmetric Asymmetric (near normal)
Low cardiac output
Evaluate further
•A velocity difference of >20 cm/sec between the righ
t and left is abnormal

75. Causes for unilateral low PSVs
•Proximal stenosis (brachiocephalic)
Parvus ‐tardus waveform or normal pattern but
asymmetrical PSVs.
•Distal stenosis (carotid bulb level)
High resistance wave form

76. Focal stenosis of the CCA
•The ratio of the highest PSV at the CCA stenosis divided
by the PSV 2 cm proximal to the stenosis should be
calculated.
PSV CCA at stenosis/PSV CCA prox.
•If the ratio is 2 or more and less than 2.99 ‐stenosis of
50% or more.
•If the ratio is 3 or more stenosis of 75% or more.
•also used if there are tandem stenosis.

78. Unusual finding in Case of CCA
occlusion
• Reversal of flow in ECA and low
resistance and low PSVs in ICA as it
is fed by collaterals.
• This is to maintain the antegrade
flow in ICA

79. CCA -mildly elevated resistance
High-velocity flow 627 cm/s,
turbulenc

81. ICA stenosis
• Most common site is ICA origin plaque extending fro
m the bulb.
• High resistance pattern in the ICA‐Stenosis distally.
• PSVs raises ‐Significant stenosis

82. Sonographic features of a severe ICA or CCA stenosis
may include the following:
• PSV greater than 230 cm/sec, a significant amount
of visible plaque (50% lumen diameter reduction on a
gray-scale image),
• Color aliasing despite a high color velocity scale
setting (100 cm/sec), Spectral broadening,
• Poststenosis turbulence at color Doppler and
• PW Doppler imaging, color bruit artifact in the
surrounding tissue of the stenotic artery, end-
diastolic velocity of greater than 100 cm/sec,
• ICA/CCA PSV ratio of 4.0 or greater.
• A high-pitched sound at PW Doppler imaging .

83. Severe stenosis (70% to near occlusion) of the ICA. Duplex US image of the left ICA
shows a high PSV (366 cm/ sec), a significant amount of visible plaque, the
presence of aliasing despite a high color scale setting (114 cm/sec), color flow
turbulence immediately distal to the stenotic segment, broadening of the PW
Doppler spectrum, and a high end-diastolic velocity (182 cm/sec

84. String sign -Near Total Occlusion

85. Total Occlusion

90. ECA
• Confirm the ECA
• Is there any reversal of flow
• Is there any internalization

92. VERTEBRAL ARTERY
LOOK AT
Normal or hypoplastic or not seen
Waveform pattern
Direction of flow
PSVs

93. Reversal of flow–
stenosis or occlusion at subclavian or brachiocephalic ar
tery
•Transient systolic reversal–in lesser digree stenosis
•High resistance wave pattern–distalocclusion or stenosis
•Low resistance wave pattern–more proximal stenosis

95. Stenosis at vertebral origin-high PSV

96. SUBCLAVIAN STEAL SYNDROME
•Subclavian artery steno‐occlusive disease proximal to the
origin of the vertebral artery.
•Resulting in decreased blood pressure in the arm distal
to the steno‐occlusive disease.
•Causes ipsilateral vertebral artery blood flow alteration
•Severe stenoses, flow reversal occurs in the ipsilateral
vertebral artery as compensatory collateral to the vascular
territory beyond the subclavian steno‐occlusive lesion.

98. Abnormal Vertebral Artery Waveforms
COMPLETE SUBCLAVIAN STEAL
Reversal of flow within vertebral artery ipsilateral to
stenotic or occluded subclavian or innominate artery
INCOMPLETE OR PARTIAL SUBCLAVIAN STEAL
Transient reversal of vertebral artery flow during systole
May be converted into a complete steal using provocative
maneuvers Suggests stenotic, not occlusive, lesion
PRESTEAL PHENOMENON “Bunny” waveform: systolic
deceleration less than diastolic flow May be converted
into partial steal by provocative maneuvers Seen with
proximal subclavian stenosis
TARDUS-PARVUS (DAMPENED) WAVEFORM Seen with
vertebral artery stenosis

102. Other wave patterns

103. PULSUS BISFERIENCE
‘‘Beat twice,’’
•Characterized by two systolic peaks with an interposed
midsystolic retraction
•Seen in AR with or without concomitant AS
Hypertophic obstructive cardiomyopathy
•Occasionally, may be seen in healthy, athletic, young in
dividuals or in older patients.

104. PULSUS ALTERNANS
•Alternating peak systolic heights on sequential beats in
a regular normal
sinus rhythm
Clinical conditions Intrinsic myocardial disease
• Ischemia
• Cardiomyopathies
• Valvularheart disease

105. ‘Water hammer pulse’’
•In aortic reagurgitation –
reversed early diastolic flow in both CCAs with elevation
of PSV and a sharp systolic upstroke

106. CAROTID DISSECTION
• Trauma ‐seat belt injury or repetitive trauma.
•Occasionally, spontaneous and isolated to the carotid a
rteries in Marfan syndrome, Ehlers‐Danlos syndrome,
fibromuscular dysplasia, hypertension, or drug abuse
•Also ‐direct extension of an aortic dissection.
•Rare but, dissection of the ICA is the most common ca
use of stroke in young patients.
•Most ICA dissections occur at the level of the carotid b
ifurcation.

107. Internal Carotid Artery Dissection:
Spectrum of Findings
INTERNAL CAROTID ARTERY
Absent flow or occlusion
Echogenic intimal flap, with or without thrombus
Hypoechoic thrombus, with or without luminal
narrowing
Normal appearance
COMMON CAROTID ARTERY
High-resistance waveform
Dampened flow
Normal appearance

108. Abnormal high-resistance waveforms (arrow) at the origin of the right ICA
with no evidence of flow distal to this point (curved arrow).

115. REFERENCE:
1. Rumack CM, Levine D. Diagnostic Ultrasound E-Book. Elsevier Health
Sciences; 2017 Aug 8.
2. Pozniak MA, Allan PL. Clinical Doppler Ultrasound E-Book: Expert
Consult: Online. Elsevier Health Sciences; 2013 Oct 24.
3. http://www.ultrasoundpaedia.com/