Ultrasonography Doppler is useful in differentiating carotid occlusion from near-occlusion. Near-occlusion is defined as severe stenosis at the bulb followed by collapse of the distal ICA (string sign). Total occlusion is characterized by absence of any flow in the extracranial ICA, while near-occlusion may show variable flow patterns. Doppler criteria for stenosis grading do not apply in near-occlusion/occlusion. CT or MR angiography can help confirm ultrasound findings of total versus near occlusion. Optimizing Doppler parameters is crucial to avoid false positive occlusion diagnoses.

1. Ultrasonografia Doppler inUltrasonografia Doppler in
diferentierea ocluziei carotidienediferentierea ocluziei carotidiene
de preocluziede preocluzie
Alexandru Andritoiu, MD, MPh
Spitalul Clinic de Urgenta Militar
Craiova
Doppler Ultrasound in theDoppler Ultrasound in the
differentiation of carotid occlusiondifferentiation of carotid occlusion
from near-occlusionfrom near-occlusion

2. TermeniTermeni
• Ocluzie
• Falsa ocluzie
• Subocluzie
• Ocluzie incompleta
• Stenoza preocluziva
• Preocluzie
Se adreseaza cel mai adesea ACI, dar si ACC sau ACE pot fi afectate

3. DefinitiiDefinitii
• Ocluzia carotidiana: absenta oricarui
flux pe traiectul ACI extracraniene
• Preocluzia carotidiana: stenoza severa
la nivelul bulbului urmata de colaps al
ACI distale (string-sign)
Thanvi B, Robertson T. Postgrad Med J 2007;83:95–99.
Simptomatica vs. Asimptomatica

4. Importanta clinicaImportanta clinica
• Relatia cu patologia
neuro-vasculara
• AIT
• Stroke
• Sdr. ischemie
cronica oculara
• Stenoza ACI
simptomatica
• Stenoza ACI
asimptomatica
• Ocluzie ACI
• -acuta
• -cronica
IMPORTANTA TERAPEUTICA

5. Importanta terapeuticaImportanta terapeutica
• Stenoza simptomatica 70%: endarterectomie-stent
• Stenoza asimptomatica: tratament farma
• Preocluzia
• Riscul operator sau interventional depasesc riscul de
stroke (meta analiza NASCET/ECST)
Exceptie: Preocluzia simptomatica cu colaps al ACI
distale: indicatie de endarterectomie (stent)-riscul de
recidiva a stroke-ului este de peste 40%
• Ocluzia acuta: tromboliza pe cateter urmata de
tratament endovascular (angioplastie si stent) sau
endarterectomie
• Ocluzia cronica: by-pass extra-intracranian (a.
temporala superf. si ACM)

6. Evolutia stenozei catre ocluzie
• Risc adesea supaestimat
Cauze
• Stenoza stransa
• Absenta stenozei semnificative
Alti factori
• placa ulcerata
• disectia
• embolia
• post-endarterectomie
J. David Spence JAMA Neurology Nov 2015

7. • Pionier al masurarii placii carotidiene (planimetrie,
volum 3D)-relatia cu RCV
• In preventia stroke-ului, tinta trebuie sa fie placa
arteriala si nu FRCV (LDL-Col)
• Doar 5% dintre pts. cu stenoza ACI ar beneficia de
revascularizare-Doar cei cu microembolizari
documentate la TCD!
• Doar prin masuri farmacologice intensive s-a observat
reducerea riscului de stroke si IMA de la 8% la 1%
• Critica excesul de stentare carotidiana din SUA pe
care-l echivaleaza cu malpraxisul!
Robarts Research Institute
Canada

8. Tehnici de diagnosticTehnici de diagnostic
• Angiografia standard
• CT-Angio
• RMN-Angio
• US
USUS
• 2D/3D (gray-scale)
• CDI
• PWD
• Slow-flow sensitivity
• Power-angio
• Photopic
• B-flow
• Sie-Flow
• CEUS
• IVUS

9. Criteriile velocimetriceCriteriile velocimetrice
Aplicabile stenozelor intre 60-90%

10. Corelatia MVRatio-%Sten ACICorelatia MVRatio-%Sten ACI
• Corelatia MVR cu stenoza ACI
masurata angiografic dupa criteriile
NASCET
• Corelatia MVR cu stenoza ACI masurata
dupa criteriile ECST.
Ranke S et al. – Stroke 1999
MVR (raportul velocitatilor medii)
Raportul intre Velocitatea medie masurata la nivelul stenozei si Velocitatea medie masurata distal de
stenoza

11. Atentie!Atentie!
• In preocluzie/ocluzie, criteriile
velocimetrice isi pierd acuratetea
diagnostica!
• Nu este recomandata utilizarea lor!

12. AngioAngio
Angio CT Angio de substractie Angio RM

13. PreocluziaPreocluzia
(1-10% din stenozele stranse)(1-10% din stenozele stranse)
• a). Rezultatul unei stenoze progresive
care devine subocluziva
• b). Rezultatul unei recanalizeri postr-
trombotice
• !!!Velocitatile sunt mari in preocluzia fara
colaps distal si pot fi mari sau f. joase in
preocluzia cu colaps complet.
• In cazul preocluziei nu se aplica grade de
severitate (%Sten)
Johansson E. Symptomatic carotid near-occlusion with full collapse might cause a very high risk of stroke.J Intern Med 2015
El-Saden SM. Imaging of the internal carotid artery: the dilemma of total versus near total occlusion. Radiology 2001

14. Carotid Artery Stenosis: Gray-Scale and Doppler US
Diagnosis Society of Radiologists in Ultrasound
Consensus Conference
• In cases of near occlusion of the ICA, the velocity
parameters may not apply, since velocities may be high,
low, or undetectable. This diagnosis is established
primarily by demonstrating a markedly narrowed lumen at
color or power Doppler US.
• Total occlusion of the ICA should be suspected when
there is no detectable patent lumen at gray-scale US and
no flow with spectral, power, and color Doppler US.
Magnetic resonance (MR) angiography, computed
tomographic (CT) angiography, or conventional
angiography may be used for confirmation in this setting.
EG Grant, Radiology 2003

15. PrePreocluziocluzia (Near-occlusion)a (Near-occlusion)
narrow and irregular flowpath within the thrombus
"trickle flow" or "string sign" is diagnostic of near-occlusion

16. Criteriile angiografice
Near-Occlusion
• Termen folosit de Gabrielsen (1981) ptr. a
descrie o stenoza stransa cu colaps distal.
• Near-occlusion with full collapse (string sign)
• Near-occlusion without colapse (nu poate fi diferentiata
de o stenoza stransa)

17. Criteriile Angio-Preocluzie

18. • …the near occlusion prognosis with full collapse
(higher risk) differs from that without full collapse
(lower risk). Patients with near-occlusion with full
collapse show compromised cerebral
hemodynamics.
• Sonography, common as the first and often only
carotid imaging, cannot distinguish near-occlusion
without full collapse from conventional stenosis with
peak systolic velocity analyzed.
AJNR Am J Neuroradiol 2016

19. Ocluzia CAR
Ocluzia acuta
• simptomatologie neurologica zgomotoasa
• urgenta neurologica-masuri complexe (unitati de
stroke)
• US-material anecogen endoluminal si absenta
semnalului Doppler
Ocluzia cronica
• bine tolerata neurologic prin instalarea mecanismelor
de autoreglare circulatorie cerebrala
• US-material ecogen (eventual placi hiperecogene) si
absenta semnalului Doppler

20. Ocluzie Car (Ocluzie Car (Gray-scaleGray-scale))

21. Doppler colorDoppler color

22. Power-angioPower-angio

23. Fluxul in ACE ipsilateralaFluxul in ACE ipsilaterala
a) Flux inversat
b) Flux internalizat

24. Echocontrast-Enhanced Ultrasound ofEchocontrast-Enhanced Ultrasound of
Extracranial Internal Carotid Artery High-Extracranial Internal Carotid Artery High-
Grade Stenosis and OcclusionGrade Stenosis and Occlusion
• Echocontrast helps to
obtain Doppler
signals, especially in
the distal parts of the
ICA.
Droste DW et al.- Stroke 1999

25. CEUS is superior to conventional Doppler US and is similar to CTA
CLINICS 2015;70(1):1-6

26. Evaluarea efectelorEvaluarea efectelor
hemodinamice cerebralehemodinamice cerebrale
• TCD
• oftalmodinamometrie
Importanta colateralelor in evolutia neurologica
ACM-CEUS

27. The 4 patterns of collateral flow via the circle of Willis to the hemisphere ipsilateral to the
symptomatic ICA occlusion. PCoA indicates posterior communicating artery.
Pattern of flow via the OphA ipsilateral to the symptomatic occluded ICA in patients with a
symptomatic ICA occlusion 0 to 6 months, 6 to 12 months, and 12 to 18 months after
symptoms occurred. Left, Patients with a unilateral ICA occlusion (n=41). Right, Patients with
a bilateral ICA occlusion (n=21).
Rutgers D et al.- Stroke 2000

28. A. OftalmicaA. Oftalmica in ocluzia ACIin ocluzia ACI
Four types of retrobulbar circulation. A
modified classification previously reported by
Costa et al. Normal = normal circulation in
patients without ICAO; Type 1 = forward OA,
CRA, and SPCA flow; Type 2a = reverse OA
and forward CRA and SPCA flow; Type 2b =
reverse OA and undetectable CRA and SPCA
flow; Type 3 = undetectable OA, CRA, and
SPCA flow
CDI observations in the four types of
circulation. Normal = normal circulation in
patients without ICAO; Type 1 = forward OA,
CRA, and SPCA flow; Type 2a = reverse OA
and forward CRA and SPCA flow; Type 2b =
reverse OA and undetectable CRA and SPCA
flow; Type 3 = undetectable OA, CRA, and
SPCA flow.

29. Flux inversat a. oftalmicaFlux inversat a. oftalmica

30. Fals diagnosticFals diagnostic
In preocluzie-ocluzie
IR in ACC crescut
PSV in ACC scazuta

31. Tromboza sTromboza stent carotidiantent carotidian
(0,5-2%)(0,5-2%)
Ocluzie de stent?

32. Augmentarea hemodinamica
(hemoabatere)
• Flux crescut in ACC contralaterala
• Flux crescut in AV ipsilaterala

33. Clinical case
S. Alexandru, 55 ani
• Dubla ocluzie ACC (cronica)
• Simptomatologie neurologica frusta
• TG 243 mg-dL

34. US Doppler CARUS Doppler CAR
ACC dreapta ACC stanga

35. DopplerDoppler aaaa.. vvertebraleertebrale
AV dreapta AV stanga
Supleere prin magistralele vertebrale

36. Doppler aa. oftalmiceDoppler aa. oftalmice
A. Oftalmica stangaA. Oftalmica dreapta

37. RMNRMN

38. Results
5000 cerebrovascular ultrasound records.
A total of 0.4% of the patients had common carotid artery occlusion (CCAO).
The mean age was 59.8 ± 14.2 years,
The male/female ratio was 2.33.
The most frequent risk factors were hypertension, ischaemic heart disease,
dyslipidemia, diabetes mellitus, and smoking.

41. Take home messageTake home message
• Ocluzia ACC este rara si se insoteste de obicei de infarct
cerebral intins la nivelul hemisferului ipsilateral
• Ocluzia ACC/ACI bilaterala este (teoretic) incompatibila
cu viata
• Rata anuala de stroke in ocluzia bilaterala ACI: 0-13%
• Cazul demonstreaza posibilitatea supravietuirii in absenta
unui stroke fatal, gratie rolului circulatiei colaterale
functionale
• Ocluzia carotidiana bilaterala-un stimul al preconditionarii
ischemice cerebrale in prevenirea leziunilor ischemice
focale

42. Ann Surg 1988

43. Ocluzia Tr.BCOcluzia Tr.BC
• o conditie rara
• simptome in teritorii vaste (circulatia cerbrala
anterioara, sistemul VB si membrul superior
drept)
• poate fi asimptomatica
• diagnostic US Doppler si angio CT (DSA) a.
subclavie dreapta, ACC dreapta si flux
retrograd in a. vertebrala ipsilaterala
Erdem Birgi et al. Subclavian steal-carotid recovery phenomenon due to innominate artery occlusion: Doppler ultrasound and
digital subtraction angiography findings and endovascular treatment. Turk Kardiyol Dern Ars. 2014; 42(4): 384-388

44. CONCLUZII
• If occlusion is confirmed by US, no further
imaging is necessary.
• US performed well in helping to differentiate
vessels with focal severe stenosis from those
with diffuse disease.
• MR-CT angiography added little in this group.
• Catheter angiography remains beneficial for
vessels with diffuse nonfocal narrowing.
El-Saden S et al. Radiology 2001

45. • CTA is suggested for current near-occlusion diagnosis.
• CTA is very accurate in separating near-occlusion from occlusion with
delayed imaging, and criteria exist to separate near-occlusion (with
and without full collapse) from conventional stenoses.
• For sonography, emphasis has often been on the separation of near-
occlusion and occlusion; possibly this can be further improved with
power Doppler and/or contrast enhancement. More important, it is
impossible to separate near-occlusion without full collapse from
conventional stenoses with sonography. This lack of sensitivity is a
relatively recent finding (from 2014).
• It seems appropriate to always perform CTA in addition because near-
occlusions can be missed with sonography.
• MRA with 2D TOF or contrast enhancement can separate some near-
occlusions from occlusion, but not all. It is uncertain whetherMRA can
consistently separate near-occlusion from conventional stenosis.
Am J Neuroradiol 2016

46. Cum putem evita diagnosticul
fals-pozitiv de ocluzie?
Optimizarea parametrilor Doppler este de o importanta
cruciala
• Transductor linear 7.5 MHz
• Obtine cele mai bune secvente ale ACI, atat in plan
transvers cat si longitudinal si cat mai distale
(retromandibular)
• Steering si color box adecvate
• Coboara PRF la cele mai mici valori posibile (sub 15
cm/sec) similar cu examinarea venoasa
• Utilizeaza Power-angio
• Creste esantionul de volum PWD la peste 2.5 mm
Utilizeaza CEUS si TCD