CAROTID DOPPLERPart II

DR.MUHAMMAD BIN ZULFIQARPGR-1 FCPS SHL

Sonographic features of severe ICA stenosis

Significant visible plaque (≥ 70% diameter reduction)

PSV > 230 cm/sec

EDV > 100 cm/sec

ICA/CCA PSV ratio ≥ 4.0

Spectral broadening

Color aliasing despite high velocity scale (100 cm/sec)

Color bruit artifact in surrounding tissue of stenosis

High-pitched sound at pulsed Doppler

Stenosis of ECA

• PSV of ECA stenosis Minimal < 200 cm/sec

Moderate 200 – 300 cm/sec Severe > 300 cm/sec

• ECA/CCA systolic ratio* < 2 ≤ 50% Ø stenosis ≥ 2 ≥ 70% Ø stenosis

Isolated ECA stenosis not clinically significant

PART II

1. Vertebral Artery2. Pathologies other than Arteriosclerotic

Disease3. Effect of extra-carotid diseases

Vertebral artery course

V1

V0

V2

V3

V4

BA

VAs asymmetric in 75 % – Left dominant in 80 %

Posteriorly directed loop when exists C1 transverse process2 VAs unite to form basilar artery: collateralization

Ultrasound of normal vertebral vessels

Cephalad flow throughout cardiac cycle Low resistance flow pattern VA origin regularly seen by experienced sonographers Size: variable & asymmetric – Mean diameter 4 mm PSV: 20 – 40 cm/sec – <10 cm/sec potentially abnormal

Vertebral artery

Vertebral vein

May occasionally be seen adjacent to VA Flow caudad & nonpulsatile

Schematic Doppler waveforms of VA

High-resistance flow in vertebral artery

High-resistance flow

No diastolic component

Distal VA stenosis or occlusion

Hypoplastic vertebral artery

Differential diagnosis:

Dizziness

Unsteady walking

Correlation with symptoms

Route of flow in left vertebral steal

Subclavian steal phenomenon refers to steno-occlusive disease of the proximal subclavian artery with

retrograde flow in ipsilateral vertebral artery

Types of subclavian steal

Transient reversal of vertebral flow during systoleConverted to partial or complete by provocative

maneuver

Pre-steal or bunny waveform

Striking deceleration of velocity in mid or late systoleHigh-grade stenosis of subclavian rather than occlusion

Incomplete steal

Complete reversal of flow within vertebral artery

Complete steal

Vertebral to subclavian steal

Presteal

Incomplete steal

Complete steal

Compared to bunny in profile

Provocative maneuver in steal syndrome

Conversion of pre-steal waveform to more pronounced steal

following deflation of pressure cuff

Inflation of pressure cuff on arm for 3 min & rapid deflationBy exercising the diseased limb also cause provocation

Pre-steal More pronounced steal

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibromuscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arterio-venous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Fibromuscular dysplasiaMiddle age women – Renal arteries – String of beads pattern

Alternating zones of vasoconstriction & vasodilatation for 3 – 5 cm

ICA frequently – VA less frequently

Usually bilateral

ICA

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibromuscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arterio-venous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Carotid & vertebral dissection

• Spontaneous dissection Bleeding from vasa vasorum Most common ICA & VA (atlas loop)

Intramural hematomaPain – Stenosis – Horner

• Vascular injury Iatrogenic: puncture – surgeryCCAIntramural hematoma ± intimal tear

• Stanford A dissection Intimal rupture in ascending aortaCCA

Dissection of aorta & cervical arteries

Patho-anatomy

Intimal rupture with false lumenOpen or secondarily thrombosed

Aorta

External intramural hematomaLumen constrictionRare intimal rupture

Cervical

Spontaneous dissection of ICAAsymmetric 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

a Longitudinal color Doppler ultrasound (US) image of an acute dissection of the internal carotid artery (ICA) with the dissection of the lumen (arrowhead) demonstrating color flow. ICA large arrow, external carotid artery (ECA) long arrow. b An abnormal high-resistance spectral Doppler US waveform is demonstrated in the dissection lumen (arrowhead). ICA large arrow, ECA long arrow. c. On day 14, there is intramural thrombus formation (arrowhead) with no evidence of color Doppler US flow within the dissection false lumen. CCA star, ICA large arrow, ECA long arrow

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

Dissection of common carotid artery

Transverse view Longitudinal viewDetection of two lumina & dissection membrane

Dissection of CCA / Stenosis Residuum after end of aortic dissection

Doppler of true lumen

Enlargement of false lumen

before cranial end

Doppler of false lumen

Stenosis of true lumen

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibromuscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arterio-venous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Vasospasm

• Causes Migraine, eclampsia, vasculitis, drug abuse, idiopathic

• Incidence Rarely identified (short duration) Occur frequently & remain undetected

• Symptoms Cerebral or ocular ischemia

• US 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

Vasospasm Severe narrowing of ICA No stenosis detected

4 days later

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibromuscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arterio-venous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Extra-cranial ICA aneurysmsColor Doppler US Power Doppler US

Incomplete delineation of aneurysm – Thrombi could not be excluded

Difficult definition for extracranial carotid artery aneurysmsdue to normal dilatation of bulb

ICA aneurysm / Parietal thrombosis

Aneurysm of proximal ICA

Parietal thrombus & homogeneous thickening of vessel wall

Longitudinal section Transversal section

CCA aneurysm / Rupture

CCA pseudoaneurysm / Rare

One month after bilateral neck dissection

CCA PseudoaneurysmLarge connecting neck

Color Doppler US CE multidetector CT

CCA PseudoaneurysmLarge connecting neck

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibro muscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arterio-venous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Arterio-venous fistulaAttempt to perform US-guided jugular catheter insertion

Turbulent flow in fistula track High-velocity turbulent flow in track

Suspicion of communication between CCA & IJV

CCAIJV

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibro muscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arterio-venous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Doppler ultrasound in arteritis“macaroni sign” & “halo sign”

• 2 types Takayasu Young female – SCA & CCAHorton Old female – SCA, AA & Temporal ACannot be differentiated using US

• US signs Macaroni Concentric hypoechoic wall thickeningHalo Dark halo around colorful lumenAll grades of stenosis – Thrombotic vessel

• DD Dissection Eccentric hypoechoic wall thickening Pronounced outward expansion

Takayasu’s arteritis Young female – SCA [‘pulseless’ disease] – CCA

CCA

Long hypoechoic wall thickening

Visualized in color Doppler as dark halo around vascular lumen

Horton's arteritis / Giant cell arteritis

Concentric hypoechoic wall thickeningSuperficial temporal artery

VA – Longitudinal view VA – Transverse view

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibromuscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arteriovenous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Carotid body tumor / Rare

Histology Paraganglioma of low malignant potential

Presentation Palpable neck mass – Headache – Neck pain

US Highly vascular mass in carotid bifurcation

Arteriography Performed preoperatively – Embolization

Treatment Resection to prevent local adverse events: Laryngeal nerve palsy – carcinoma

invasion

Result Local recurrence 6% – Distant metastasis 2%

Carotid body tumor Highly vascular mass in carotid bifurcation

Causes of carotid artery diseases

Arteriosclerotic disease

Non-arteriosclerotic diseasesFibromuscular dysplasia DissectionVasospasm Aneurysm & pseudoaneurysm

Arterio-venous fistula Arteritis: Takayasu – Horton Carotid body tumor Idiopathic carotidynia

Most common cause

Diagnosis of idiopathic carotidyniaInternational Headache Society (IHS)1

• At least one of following over CA: TendernessSwellingIncreased pulsations

• Pain over affected side of neck that may project to head

• Appropriate investigations without structural abnormalityRecent publications demonstrate radiological findings2

• Self-limiting syndrome of less than 2 weeks duration

Idiopathic carotidynia

US findings comparable to dissection

Enhanced tissuearound carotid artery

CE T1-weighted MRIUS of distal CCA

Hypo-echoic soft tissuearound carotid artery

Three months later

Resolution of abnormalsoft tissue

Spontaneous dissection & carotidynia

Spontaneous dissection Carotidynia

Location Beyond bifurcation At or near bifurcation

Thickening layersOne wall layer 2 wall layers

Stenosis May be detectable Not detectable

Pain Head Neck

In unclear cases, MRI enables differentiation

Doppler US of carotid arteries

Anatomy of carotid arteries

Normal Doppler US of carotid arteries

Causes of carotid artery disease

Effect of extra-carotid diseases

Effect 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

Idiopathic dilated cardiomyopathy

Pulsus alternans

PSV oscillating between two levels on sequential beats

Cardiac rhythm remains regular throughout

Aortic regurgitation

Bisferiens waveform [“beat twice” in Latin]

Two systolic peaks separated by midsystolic retractionDicrotic notch

Found also with hypertrophic obstructive cardiomyopathy

Severe aortic regurgitation

Normal or elevated PSV followed by precipitous declineRevered flow during diastole

Water-hammer spectral appearance

CCA

Aortic stenosisRCCA – Tardus Parvus LCCA – Tardus Parvus

RVA – Tardus Parvus

Right innominate artery stenosis RCCA – Tardus-Parvus LCCA – Normal waveform

RVA – Reversed flow

Right innominate artery stenosis

RICA : to-and-fro flow

RCCA : to-and-fro flow

RVA : reversed flow

RSCA : damped flow

Right carotid steal

High cardiac output: Hypertensive patientsYoung athletes

High flow > 125 cm/sec in both CCAs

Poor cardiac output: CardiomyopathiesValvular heart diseaseExtensive myocardial

infarction

Low flow < 45 cm/sec in both CCAs

Arrhythmias can be real problem

Normal PSV in CCA (45 – 125 cm/sec)

ICA

High-grade stenosis distally (intracranial ICA)

Major occlusive lesions of cerebral arteries (MCA, ACA)

Massive spasm of cerebral arteries from intracranial hemorrhage

Stenosis of intra-cranial ICAHigh resistance waveform

Advantages of power mode Doppler

• Angle independent

• No aliasing

• Increases accuracy of grading stenosis

• Distinguish pre-occlusive from occlusive lesions“detect low-velocity blood flow”

• Superior depiction of plaque surface morphology

Disadvantages of power mode Doppler

• Does not provide direction of flowNew machines provide direction of flow in power mode

• Does not provide velocity flow information

• Very motion sensitive (poor temporal resolution)

Causes of image/Doppler mismatch

• Cardiac arrhythmia• Severe aortic stenosis• Hypotension or hypertension• Tortuous vessels• Hypoechoic, anechoic or calcified plaques • Long segment high grade stenosis• Pre-occlusive lesion• Tandem lesion• Contra-lateral carotid stenosis• Carotid dissection

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

Thank You