ICTUS CEREBRI, STENOSI CEREBROVASCOLARI E ULTRASUONI: DIAGNOSI E TERAPIA CON IL DOPPLER TRANSCRANICO
Dr A. CostaU.O. Neurologia VascolareA.O. Spedali Civili di Brescia
Indicazioni
Visualizzare le occlusioni e le stenosi intracraniche nelle principali arterie
Valutare gli effetti emodinamici intracranici in presenza di stenosi o occlusioni extracraniche
Monitorare la ricanalizzazione dei vasi intracranici nella fase acuta dell’ictus
Monitorare l’emodinamica cerebrale intracranica Dopo emorragia subaracnoidea InIn pazienti con aumentata ICP Durante/dopo procedure di rivascolarizzazione extracranica
Endarterectomia carotidea Angioplastica
Durante/dopo interventi neuroradiologici Balloon occlusion Coiling of AVM
Durante interventi cardiochirurgiciVisualizzazione e quantificazione dello shunt destro-sinistro
Patent foramen ovale
Indicazioni (2)Test funzionali
Stimulazione delle arteriole intra craniche con CO2 o altri farmaci vasoattivi
Lateralizzazione del linguaggio prima della neurochirurgia
NEWBrain perfusion imagingTrombolisi con ultrasuoniStratificazione del richio
Diagnostic Criteria – Stenosis
Increased flow velocity – generally focalDisturbed flow
Turbulence; spectral broadeningCovibration phenomena
Vibration of the vessel wall & surrounding soft tissue
Drop in post-stenotic velocityChanges in post-stenotic waveform
morphologyProlonged systolic upstrokeDecreased pulsatility
Diagnostic Criteria – OcclusionAbsence of arterial signal at expected depth
Presence of signals in vessels which communicate with the occluded artery
Altered flow in communicating vessels, indicating collateralization
Occlusione Arteria Cerebrale Media M1 - Criteri diagnostici
NAIS TCCS Consensus
Il segnale di flusso dell’MCA è assente in contemporanea alla visualizzazione delle restanti arterie del circolo anteriore
Il segnale di flusso dell’MCA è assente in contemporanea alla visualizzazione delle restanti arterie del circolo anterioreo delle vene profonde cerebrali o del circolo controlaterale
Sensibilità 85-100% Specificità 90-98%
Occlusione ICA a T - Criteri diagnostici
NAIS TCCS Consensus
Il segnale di flusso dell’MCA, ICA distale e A1 è assente in contemporanea alla visualizzazione dalla finestra omolaterale di A1 del circolo controlaterale o omolaterale
Il segnale di flusso dell’MCA, ICA distale e A1 è assente in contemporanea alla visualizzazione dalla finestra omolaterale di A1 del circolo controlaterale o omolateraleLa visualizzazione delle vene profonde cerebrali, di A2 o del circolo controlaterale aumenta la credibilità della diagnosi.Meglio se confermata dalla riduzione della velocità di flusso diastolico sull’ICA cervicale o sulla CCA o dalla presenza di flusso oscillante
Sensibilità 70-90% Specificità 90-95%
Occlusione segmento distale M1 o di multipli rami di M2- Criteri diagnostici
NAIS TCCS Consensus
Differenze del 30% nella velocità di picco sistolico nel segmento prossimale di M1
Velocità di fine diastole inferiore a 26 cm/s e indice di fine diastole inferiore a 2.5 (se >2.5 indice di occlusione M1)(?).Calcolare l’indice di asimmetria se non vi sono alterazioni del flusso lungo l’ICA o M1 bilateralmente.Basse velocità di flusso vanno comunque tenute in considerazione in relazione al beneficio derivante dalla trombolisi
Sensibilità 70-90% Specificità 90-95%
Stenosi M1 (o del segmento distale dell’ICA) – Criteri diagnostici
NAIS TCCS Consensus
Significativa (cioè superiore al 50%) se la velocità di picco sistolico dell’MCA o ICA distale è superiore a 220 cm/s.
Non vi sono dati validati per definire una diagnosi.
Sensibilità 70-90%? Specificità 90-95%?
MCA Stenosis
Pitfalls & Diagnostic AccuracyLack of flow signal due to an inadequate temporal
windowMisinterpretation of hyperdynamic collateral
channels or AVM feeders as stenosisDisplacement of arteries because of a space-
occupying lesionMisinterpretation of physiologic variables in the
circle of WillisMisdiagnosis of vasospasm as stenosisMisinterpretation of reactive hyperemia following
spontaneous recanalization as stenosis
Pitfalls & Diagnostic AccuracyVertebral-Basilar SystemNormal flow and size of vessels are highly
variableLocation and course of the arteries are
unpredictableDifficulty in reliably identifying the junction of
the vertebral arteries Absence of the vertebral artery flow signal on one
side may not represent diseaseLack of flow in one vertebral artery distally, above the
origin of the PICA due to vertebral artery hypoplasia Occlusion of one vertebral artery or a “top of the
basilar” occlusion does not necessarily lead to relevant flow abnormalities
Summary of findingsIntracranial Steno-Occlusive Disease
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
Intracranial Steno-Occlusive Disease:
Conventional angiography
Anterior Circulation
70-90 90-95
Posterior CirculationOcclusion
50-80 80-96
Copyright 2004 American Academy of Neurology
19
Summary of findingsIntracranial Steno-Occlusive Disease (Continued )
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
MCA 85-95 90-98
ICA, VA, BA 55-81 96
Recommendation: Data are insufficient to establish TCD criteria for greater than 50% stenosis or for progression of stenosis in intracranial arteries (Type U).
Copyright 2004 American Academy of Neurology
Summary of findingsAcute cerebral infarction
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
Acute cerebral infarction
85-95 90-98
Recommendation: TCD is probably useful for the evaluation of patients with suspected intracranial steno-occlusive disease, particularly in the ICA siphon and MCA (Type B, Class II evidence). The relative value of TCD compared with MRA or CTA remains to be determined (Type U). Data are insufficient to give a recommendation regarding replacing conventional angiography with TCD (Type U).
Summary of findingsExtracranial ICA Stenosis
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
Extracranial ICA Stenosis:
Conventional angiography
Single TCD variable
3-78 60-100
TCD Battery 49-95 42-100
TCD Battery & Carotid Duplex
89 100
Recommendation:TCD is possibly useful for the evaluation of severe extracranial ICA stenosis or occlusion (Type C, Class II-III evidence).
Transcranial Color-Coded Sonography (TCCS) or Imaging
TCD
Summary of findingsIschemic Cerebrovascular Disease
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
ACoA Collateral Flow
100 100
PCoA Collateral Flow
85 98
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
Intracranial Steno-Occlusive Lesions
Any Up to 100 Up to 83
Summary of findingsIschemic Cerebrovascular Disease
(Continued)
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
/= 50% Stenosis
MCA 100 100
ACA 100 100
VA 100 100
BA 100 100
PCA 100 100
Summary of findingsIschemic Cerebrovascular Disease
(Continued)
Summary of findingsIschemic Cerebrovascular Disease
(Continued)
Recommendation: (CE)-TCCS is probably useful in the evaluation and monitoring of patients with ischemic cerebrovascular disease (Type B, Class II-IV evidence).
Summary of findingsHemorrhagic Cerebrovascular DiseaseINDICATION SENSITIVITY
(%) SPECIFICITY
(%) REFERENCE STANDARD
Parenchymal Hypoechogenicity in MCA Distribution
69 83 Computed tomographic
scan
Recommendation: (CE-) TCCS is probably useful in the evaluation and monitoring of patients with aneurysmal SAH or intracranial ICA/MCA VSP following SAH (Type B, Class II-III evidence). Data are insufficient regarding the use of TCCS to replace CT for diagnosis of ICH (Type U).
Summary of findingsCerebral Thrombolysis
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
Cerebral Thrombolysis
Conventional angiography, magnetic resonance angiography, clinical outcome
Complete Occlusion
50 100
Partial Occlusion
100 76
Recanalization 91 93
Summary of findingsCerebral Thrombolysis (continued)
Recommendation: TCD is probably useful for monitoring thrombolysis of acute MCA occlusions (Type B, Class II-III evidence). Present data are insufficient to either define the optimal frequency of TCD monitoring for clot dissolution and enhanced recanalization or to influence therapy (Type U).
Summary of findingsCarotid Endarterectomy (CEA)
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
Carotid Endarterectomy
(CEA):
EEG, magnetic resonance imaging, clinical outcomes
Recommendation: CEA monitoring with TCD can provide important feedback pertaining to hemodynamic and embolic events during and after surgery that may help the surgeon take appropriate measures at all stages of the operation to reduce the risk of perioperative stroke. TCD monitoring is probably useful during and after CEA in circumstances where monitoring is felt to be necessary (Type B, Class II-III evidence).
Summary of findingsVasomotor Reactivity (VMR) Testing
Recommendation: TCD vasomotor reactivity testing is considered probably useful for
–the detection of impaired cerebral hemodynamics in patients with asymptomatic severe (>70%) stenosis of the extracranial ICA–patients with symptomatic or asymptomatic extracranial ICA occlusion and patients with cerebral small artery disease (Type B, Class II-III evidence).
How the results from these techniques should be used to influence therapy and affect patient outcomes remains to be determined (Type U).
Summary of findingsDetection of Cerebral Microemboli
INDICATION SENSITIVITY (%)
SPECIFICITY (%)
REFERENCE STANDARD
Cerebral Microembolization
Experimental model, pathology, magnetic resonance imaging, neuropsychological tests
Recommendation: TCD is probably useful to detect cerebral microembolic signals in a wide variety of cardiovascular/ cerebrovascular disorders/procedures (Type B, Class II-IV evidence). However, data at present do not support the use of TCD for diagnosis or for monitoring response to antithrombotic therapy in ischemic cerebrovascular disease in these settings(Type U).
TCD in fase acutaConclusioni
Utile nell’approccio diagnostico in fase acutaConsente il monitoraggio dei vasi intracranici
sia in fase acuta che a lungo termineMigliora la trombolisi sia farmacologica che
spontaneaConsente il monitoraggio dell’interventistica
cardio-cerebrovascolareHa valore prognostico in fase acuta del TIA
(stenosi e microemboli) e dell’ictus acuto (stenosi)
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