CARATID DOPPLER

1. ULTRASOUND
EVALUATION OF
CAROTID
ARTERIES
Dr. Suraj Jaiswal

2. NORMAL ANATOMY

3. DEVELOPMENT OF CAROTID ARTERIES

4. • CCA ascends anterolaterally up the neck medial to the jugular vein and lateral to
thyroid.
• Each artery measures 6-8mm in diameter.
• CCA dilates in common carotid bulb and bifurcates into ICA and ECA at C3-C4
level.
• ECA assumes an anteromedial course off the carotid bulb 70% of time. It has
branch vessels that supply head and face and measures 3-4mm in diameter.
• ICA assumes a posterolateral course , supplies brain and measures 5-6mm.
• Portion of arterial wall between ICA and ECA at their origin is called flow divider.
CAROTID ARTERY ANATOMY

5. INTERNAL CAROTID
ARTERY
There are 7 segments in the Bouthillier
classification
Cervical segment
Petrous segment
Lacerum segment
Cavernous segment
Clinoid segment
Ophthalmic (supraclinoid) segment
Communicating (terminal) segment

6. EXTERNAL CAROTID
ARTERY
Branches:
1. Superior thyroid artery
2. Lingual artery
3. Facial artery
4. Ascending pharyngeal artery
5. Occipital artery
6. Posterior auricular artery
7. Internal maxillary artery
8. Superficial temporal artery

7. • The vertebral artery is the first branch of the subclavian artery,
arising from the highest point of the subclavian arch.
• At the sixth cervical vertebra, the Vertebral artery runs
posteriorly to travel upward through the transverse foramen
of cervical vertebrae.
• Course: can pass through foramen transversarium of C7
(10%)
Termination: B/L VA joins to form the basilar artery
• VA may terminate in PICA rarely.
VERTEBRAL ARTERY

8. MOST IMPORTANT VARIANTS OF THE SUPRA-
AORTIC ARTERIES
common origin of the innominate
artery and left common carotid
artery from the aortic arch (13%);
persisting communicating trunk
arising from the aortic arch and
giving off first the left common
carotid artery and then the
innominate artery (9 %);
bilateral innominate artery dividing
into the common carotid and
subclavian arteries (1 %);
situs inversus (very rare).

9. VARIANTS RESULTING FROM ELONGATION OF ICA
Variants

10. SONOGRAPHIC ANATOMY

11. INDICATIONS OF CAROTID ULTRASOUND
• Evaluation of pts with TIAs
• Evaluation of pts with CVA
• Evaluation of carotid bruits
• Follow up of known disease
• Monitor endarterectomy results/stents, bypass
• Preoperative screen prior to major vascular surgery
• Evaluation of potential source of retinal emboli
•Evaluation of pulsatile neck mass
• Follow up of carotid dissection

12. Right side of the couch
with scanning arm resting
on the patient’s upper
chest.
PROTOCOL
Set-up: examiner/patient positioning
Patient:
Examiner:
The patient should lay on the couch in a supine position, head
resting on the couch. Their head should be hyper-extended
and turned 45° away from the side being examined.
Option 1: Side
Behind the patient’s head
with scanning arm resting
on the couch.
Option 2: Head

13. Set-up: transducer/preset selection
Transducer selection:
• Predominately use a mid/high frequency (6-15 MHz or
similar) linear array transducer depending on depth of
vessels.
• Use a low frequency (1-5 MHz or similar) curvilinear
array transducer if vessels are deep, short neck or vessel
segments near the base of the skull.
U/S scanner settings:
Select the ‘carotid’ preset on the ultrasound machine as a starting point. The B-mode,
colour flow Doppler and pulsed wave Doppler settings will need to be optimised
during the examination.

14. The examination sequence:
A typical carotid examination takes place as follows:
◦ STEP 1. The best way to do this is to place the transducer in A transverse plane and to sweep
the probe slowly upward from the level of the clavicle to the jaw. This can be done
◦ In gray-scale mode and, if needed, with color doppler imaging. This scan is used to obtain an
overall evaluation of carotid anatomy
◦ STEP 2 The transducer position that best displays the carotid vessels in a longitudinal view
will typically be from a lateral approach

16. Intima-Media Complex
Normal value ≤ 0.8 mm
Wall of CCA, bulb, or ICA
Best measured on far wall
Only intima & media included

17. ◦ STEP 3. DOPPLER IMAGING OF THE CCA
◦ Start the survey of the CCA low in the neck, moving upward to the bifurcation. Record a
velocity spectrum from the CCA low in the neck record a second waveform close to the
bifurcation and the following points should be noted:
◦ (1) the measurement point should be 2 to 4 cm below the carotid bulb;
◦ (2) care should be taken that the sample volume is squarely within the center of the
vessel
◦ (3) the doppler angle must be low enough (60 degrees or less) to measure the peak
systolic velocity accurately

19. STEP 4. BIFURCATION SURVEY
◦ The carotid bifurcation is imaged with B-mode and color Doppler imaging in
both the longitudinal and transverse planes. The purpose of this survey is to
confirm the patency of the arteries, to identify and to localize plaque and
associated flow abnormalities, and to define the junction of the ECA and ICA
or flow divider in order to help define plaque location.

20. ◦ STEP 5. VESSEL IDENTITY
◦ Confirm the identity of the ICA and ECA by their Doppler spectral
signatures by anatomic features and by performing the temporal tap
maneuver
◦ The proper identification of the branch vessels is essential because only
significant ICA stenoses are treated.
◦ Intervention is rare on ECA stenotic lesions and only in cases of complex
multiple occlusions of the carotid and vertebral arteries.
◦ A color Doppler image of the proximal ECA and ICA should be recorded.
As a minimum, a proximal and distal ICA duplex image should be
recorded

21. Features That Identify the ECA & ICA
Features External Carotid
Artery
Internal Carotid
Artery
Size Usually smaller of the
two
Usually Larger of the
two
Branches Always Very rarely
Position Anteromedial Posterolateral
Doppler
Characteristics
High resistance Low resistance
Response to
Temporal Tap
Well perceived
Oscillations
Poorly Perceived /
absent oscillations

25. Normal doppler waveforms

26. STEP 6. STENOSIS DETECTION AND DOCUMENTATION
◦ When a stenosis is present, properly angle-corrected velocity estimates are made in the
stenosis
◦ Color Doppler images that document the location and length of the stenosis are also
recorded
STEP 7. EVALUATION OF THE VERTEBRAL ARTERIES
◦ images of each vertebral artery with representative Doppler spectral waveforms, including
measurement of the peak systolic and end-diastolic velocities, are recorded.
STEP 8. ASSESSMENT OF THE SUBCLAVIAN ARTERIES
◦ Additional images of the subclavian arteries are acquired either as part of a fixed protocol
or as an option in cases of vertebral artery disease.

27. Protocol for vertebral artery
Longitudinal VA between transverse processes
◦ - Direction of flow
◦ - Waveform configuration
◦ - Measure PSV
Ultrasound of normal vertebral vessels
Vertebral artery
• Cephalad flow throughout cardiac cycle
• Low resistance flow pattern
Size: variable & asymmetric - Mean diameter 4 mm
PSV: 20 - 40 cm/sec - <10 cm/sec potentially abnormal
Vertebral vein
• May occasionally be seen adjacent to VA
• Flow caudad & non pulsatile

29. Optimal Scanning Techniques and Doppler Settings
◦ Doppler Equation US equipment calculates the velocity of blood flow according to the Doppler equation:
where f is the Doppler shift frequency,
f0 is the transmitted ultrasound frequency,
V is the velocity of reflectors (red blood cells),
(theta, also referred to as the Doppler angle) is the angle between the transmitted beam and the direction of
blood flow within the blood vessel (the reflector path), and
C is the speed of sound in the tissue (1540 m/sec)

30. ◦ The Doppler angle should not exceed 60°, as measurements are likely to be inaccurate.
Our preferred angle of incidence is 45°+/- 4°.
◦ The optimal position of the sample volume box in a normal artery is in the mid-lumen
parallel to the vessel wall, whereas in a diseased vessel, it should be aligned parallel to
the direction of blood flow.
◦ In the absence of plaque disease, the sample volume box should not be placed on the
sharp curves of a tortuous artery, as this may result in a falsely high-velocity reading. If
the sample volume box is located too close to the vessel wall, artificial spectral
broadening is inevitable.

31. SAMPLE VOLUME BOX AND ANGLE CORRECTION

33. SPECTRAL BROADENING
◦ Spectral broadening occurs when there is a wide range of velocities in the Doppler sample
volume. There is filling in of the spectral window or area under the spectral line This finding is
◦ typically seen with stenosis; however, spectral broadening may be related to technical factors
◦ and other causes of turbulent flow. These include the following:
1. A large Doppler sample volume that includes all or most of the artery lumen
2. High gain settings
3. Increased vessel wall motion
4. High velocities contralateral to a severely diseased or occluded ICA
5. Tortuous vessels

34. SPECTRAL BROADENING

35. COLOR DOPPLER SAMPLING WINDOW ADJUSTMENT

36. Color scale adjustment

38. ADJUSTMENT OF THE COLOR SCALE IN A NEAR OCCLUSION.

39. Color gain adjustment

40. Plaque imaging

41. GRADING OF PLAQUE
Type Description
1 Dominantly echolucent with thin echogenic cap
2 Substantially echolucent plaque with small areas of echogenicity
3 Dominantly echogenic lesions with small area(s) of echolucency (<25%)
4 Uniformly echogenic lesions (equivalent to homogeneous)

43. Plaque morphology
◦ HOMOGENOUS ◦ HETEROGENOUS

44. PLAQUE ULCERATION
Ultrasound Features of plaque ulceration
Focal depression or break in plaque surface
Anechoic region within plaque extending to vessel
lumen
Eddies of color within plaque

45. INTRAPLAQUE HEMORRHAGE

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

47. Primary Parameters Additional Parameters
Degree of
Stenosis%
ICA
PSV(cm/sec)
Degree of plaque(%) ICA/CCA PSV
Ratio
ICA EDV(cm/sec)
Normal <125 None <2.0 <40
<50 <125 <50 <2.0 <40
50-69 125-230 ≥50 2.0-4.0 40-100
≥70 but less than
near
occlusion
>230 ≥50 >4.0 >100
Near occlusion High, low, or
undetectable
Visible Variable Variable
Total occlusion Undetectable Visible, no detectable
lumen
NA NA
Criteria for Diagnosis of ICA Stenosis with Gray-Scale and Doppler US

48. Estimation of carotid stenosis
Diameter Reduction Surface Reduction

52. Vertebral artery & subclavian steal
• IDENTIFICATION OF THE VERTEBRAL ARTERY IS ACHIEVED BY LOCATING THE CCA IN A
SAGITTAL VIEW AND SWEEPING THE TRANSDUCER LATERALLY TO THE TRANSVERSE
PROCESSES OF THE CERVICAL SPINE
• ON THE BASIS OF THE HEMODYNAMIC CHANGES IN THE VERTEBRAL ARTERY, THERE ARE
THREE TYPES OF SUBCLAVIAN STEALS.
 IN OCCULT STEAL (MINIMAL HEMODYNAMIC CHANGES), PW DOPPLER IMAGING MAY
SHOW ANTEGRADE FLOW WITH MIDSYSTOLIC DECELERATION, WHICH MAY
TEMPORARILY CONVERT TO A MORE ABNORMAL WAVEFORM
 PARTIAL SUBCLAVIAN STEAL CORRESPONDS TO MODERATE HEMODYNAMIC CHANGES.
THE PW DOPPLER SPECTRUM SHOWS PARTIALLY REVERSED FLOW. THE PW DOPPLER
SPECTRUM IN OCCULT AND PARTIAL SUBCLAVIAN STEAL MAY RESEMBLE THE PROFILE
IMAGE OF A RABBIT (THE “BUNNY RABBIT” SIGN)
 IN COMPLETE (FULL) SUBCLAVIAN STEAL, FLOW IN THE VERTEBRAL ARTERY IS
COMPLETELY REVERSED . THIS MAY BE ASSOCIATED WITH ISCHEMIC SYMPTOMS IN THE
IPSILATERAL ARM.

54. LIMITATIONS OF CAROTID US EXAMINATION
◦ Short muscular neck
◦ High carotid bifurcation
◦ Tortuous vessels
◦ Calcified shadowing plaques
◦ Surgical sutures, postoperative hematoma,
◦ Central line
◦ Inability to lie flat in respiratory or cardiac disease
◦ Inability to rotate head in patients with arthritis
◦ Uncooperative patient

55. NON ARTERIOSCLEROTIC CAROTID DISEASES
◦ Fibromuscular dysplasia
◦ Dissection
◦ Vasospasm
◦ Aneurysm & pseudoaneurysm
◦ Takayasu Arteritis
◦ Carotid Body Tumour

56. FIBROMUSCULAR DYSPLASIA
◦ Middle age women- Renal arteries- String of beads pattern
Alternating zones of vasoconstriction & vasodilation for 3 - 5 cm
ICA frequently- VA less frequently
Usually bilateral

57. CAROTID AND VERTEBRAL ARTERY DISSECTION
• Spontaneous dissection Bleeding from vasa vasorum
Most common ICA & VA (atlas loop)
Intramural hematoma
Pain - Stenosis - Horner
• Vascular injury Iatrogenic: puncture - surgery CCA
Intramural hematoma +/-
intimal tear
• Stanford A dissection Intimal rupture in ascending aorta &CCA

58. DISSECTION OF AORTA & CERVICAL ARTERIES
External intramural hematoma
Lumen constriction
Rare intimal rupture
Patho-anatomy
Cervical Aorta
Intimal rupture with false lumen
Open or secondarily thrombosed

59. SPONTANEOUS DISSECTION OF ICA
Asymmetric wall hematoma- Lumen stenosis-Expansion to outside
Diagnostic criteria (one sufficient)
Intramural hematoma
Intimal rupture/double lumen
Distal stenosis or occlusion
Symptoms: acute pain, Horner,
Course: recanalization in few weeks

60. SPONTANEOUS DISSECTION OF VA
Wall hematoma in V1
Diagnostic criteria (one sufficient)
Intramural hematoma(asymmetric, not concentric)
Intimal rupture/double lumen (rare)
Double lumen in V2

61. DISSECTION OF COMMON CAROTID ARTERY
Transverse view
Detection of two lumina & dissection membrane
Longitudinal view

62. DISSECTION OF CCA / STENOSIS
Doppler of true lumen
Doppler of false lumen

63. VASOSPASM
Causes Migraine, eclampsia, vasculitis, drug abuse, idiopathic
Incidence Rarely identified (short duration) Occur frequently & remain undetected
Symptoms Cerebral or ocular ischemia
USG Direct &/or indirect signs of severe stenosis
Far above bifurcation - Sometimes bilateral
Complete regression in hours to days – Relapse
Dd Dissection: wall hematoma - regression in weeks
Treatment Calcium antagonists

64. VASOSPASM
Severe narrowing of ICA No stenosis Detected
4 days later

65. ICA ANEURYSM

66. CCA ANEURYSM / RUPTURE

67. CCA PSEUDOANEURYSM / RARE
Color Doppler USG CE Multidetector CT
CCA PSEUDOANEURYSM
LARGE CONNECTING NECK

68. TAKAYASUS ARTERITIS
Young female- SCA ('pulseless’ disease] - CCA
‘Macaroni sign’ in the right common carotid artery detected by carotid ultrasound.
Long, homogeneous, isoechoic, circumferential wall thickening of the common
carotid arteries
is demonstrated

69. CAROTID BODY TUMOUR
HIGHLR VASCULAR MASS IN CAROTID BIFURCATION

70. EFFECTS OF EXTRA-CAROTID DISEASES
◦ Idiopathic dilated cardiomyopathy
◦ Aortic regurgitation
◦ Aortic stenosis
◦ Stenosis of right innominate artery or origin of LCCA
◦ High & low PSV in CCA
◦ Stenosis of intra-cranial ICA

71. IDIOPATHIC DILATED CARDIOMYOPATHY
PSV oscillate between two levels on sequential beats
Cardiac rhythm remains regular throughout.
Pulsus Alternans

72. AORTIC REGURGITATION
Two systolic peaks with a mid- systolic dip.
Also found in HOCM
Pulsus Bisferiens

73. SEVERE AORTIC REGURGITATION
Normal or elevated PSV with precipitous deceleration of flow in late systole,
sustained reversal of flow through diastole.
Water-Hammer spectral Appearance

74. AORTIC STENOSIS
A delayed systolic upstroke (prolonged acceleration time) with blunted amplitude and rounded waveform
appearance
Pulsus Tardus et Parvus

75. Intracranial ICA Stenosis
High-grade stenosis distally (intracranial ICA)
Major occlusive lesions of cerebral arteries (MCA, ACA)
Massive spasm of cerebral arteries from intracranial haemorrhage
High Resistance Waveform

76. Normal PSV in CCA (45 - 125 cm/sec)
High flow > 125 cm/sec in both CCAs
High cardiac output: Hypertensive patients
Young athletes
Low flow < 45 cm/sec in both CCAs
Poor cardiac output: Cardiomyopathies
Valvular heart disease
Extensive myocardial infarction

77. STANDARD REPORTING FORMAT