Stroke ImagingStroke Imaging

Dr Kneale MetcalfDr Kneale Metcalf

Stroke Physician (NNUHFT)Stroke Physician (NNUHFT)

OverviewOverview

Modalities availableModalities available When to use?When to use? TargetsTargets Real world imagingReal world imaging Future aspirationsFuture aspirations

Hyperacute StrokeHyperacute Stroke

Diagnosis difficultiesDiagnosis difficulties

Patient stability issuesPatient stability issues VomitingVomiting AirwayAirway Low GCSLow GCS SeizuresSeizures

CT ScanCT Scan

First time every timeFirst time every time ?? Posterior, late presentation?? Posterior, late presentation

FastFast SafeSafe

? Radiation? Radiation Available Available

CT ScannerCT Scanner

Early CT scanEarly CT scan

Give Radiologist correct informationGive Radiologist correct information TIME of onset neurologyTIME of onset neurology Side and details of neurologySide and details of neurology Associated headache?Associated headache? Trauma?Trauma? Anticoagulant?Anticoagulant? Relevant PMHRelevant PMH

CancerCancer StrokeStroke Neurosurgery / clips etc.Neurosurgery / clips etc.

Early CT scanEarly CT scan

Often normalOften normal

Why do?Why do? Exclude haemorrhageExclude haemorrhage Exclude tumourExclude tumour Grade for thrombolysis riskGrade for thrombolysis risk

Dense Middle Cerebral Dense Middle Cerebral ArteryArtery

Do early infarct signs Do early infarct signs matter?matter?

Help confirm diagnosisHelp confirm diagnosis

Dense middle cerebral arteryDense middle cerebral artery 10% chance opening with IV thromolysis10% chance opening with IV thromolysis ? May lead to intra-arterial or mechanical ? May lead to intra-arterial or mechanical

treatmentstreatments

Prognosis for thrombolysisPrognosis for thrombolysis 1/3 MCA territory1/3 MCA territory

ASPECTSASPECTS

Canadian studyCanadian study Academic CT head interpretationAcademic CT head interpretation Leads to 10 point scoring system on Leads to 10 point scoring system on

plain axial CT headplain axial CT head Scores of <7 increased functional Scores of <7 increased functional

dependence + increased risk of dependence + increased risk of deathdeath

ASPECTSASPECTS

Scored from two axial slicesScored from two axial slices One at thalamic level / basal gangliaOne at thalamic level / basal ganglia One just above ganglionic structures One just above ganglionic structures

(such that none are seen)(such that none are seen) 10 points 10 points

One subtracted for each area of early One subtracted for each area of early ischemic change (thus score 10=normal ischemic change (thus score 10=normal scan)scan)

Core messageCore message

Extensive early infarction may be Extensive early infarction may be poor prognostic indicator for poor prognostic indicator for outcome from thrombolysisoutcome from thrombolysis

Intracerebral Intracerebral HaemorrhageHaemorrhage

Main causesMain causes HypertensionHypertension Cerebral Amyloid Angiopathy (CAA)Cerebral Amyloid Angiopathy (CAA) RaritiesRarities

Hypertensive bleedHypertensive bleed

Cerebral Amyloid Cerebral Amyloid AngiopathyAngiopathy

Can be more subtleCan be more subtle

Core messageCore message

Main causes of intracerebral Main causes of intracerebral haemorrhage are amyloid haemorrhage are amyloid angiopathy and hypertensionangiopathy and hypertension

TumourTumour

Can be subtleCan be subtle History reviewHistory review

Non acute onsetNon acute onset SeizuresSeizures HeadacheHeadache CancerCancer

Plain CT may not showPlain CT may not show ContrastContrast

Subtle sub-acute LEFT Subtle sub-acute LEFT weaknessweakness

Post contrastPost contrast

Brain tumoursBrain tumours

Often contrast Often contrast enhance enhance

May have vasogenic May have vasogenic oedemaoedema

May respect grey / May respect grey / white junctionwhite junction

Other mimicsOther mimics

Subdural haematoma Subdural haematoma Sub arachnoid haemorrhageSub arachnoid haemorrhage

++++

Subdural haematoma Subdural haematoma

Sub arachnoid Sub arachnoid haemorrhagehaemorrhage

Don’t miss mimicsDon’t miss mimics

History just as important as the History just as important as the scan!scan!

Timing of CT changesTiming of CT changes

InfarctInfarct

HaemorrhageHaemorrhage

HaemorrhageHaemorrhage

Core messageCore message

After 10-14 days both haemorrhage After 10-14 days both haemorrhage and infarct both look like a black and infarct both look like a black holehole

Important to be able to distinguish Important to be able to distinguish old from new infarctsold from new infarcts

Urgent Scans Urgent Scans

% of URGENT scans performed % of URGENT scans performed within 60mins of arrival to hospital within 60mins of arrival to hospital (Best Prac + NICE quality standard)(Best Prac + NICE quality standard)

90% by April 201190% by April 2011 Best practice = scan + reportBest practice = scan + report

What are indications for What are indications for an urgent scan?an urgent scan?

GCS <13GCS <13 On WarfarinOn Warfarin Bleeding tendencyBleeding tendency Severe headacheSevere headache Papilloedema / neck stiff / feverPapilloedema / neck stiff / fever Progressive / fluctuating symptomsProgressive / fluctuating symptoms For thrombolysisFor thrombolysis

MRI scanMRI scan

Why do an MRI?Why do an MRI?

If stroke uncertainIf stroke uncertain To confirm vascular territoryTo confirm vascular territory Look for multi-territory involvementLook for multi-territory involvement

Look for previous haemorrhageLook for previous haemorrhage

Main MRI sequencesMain MRI sequencesDiffusionDiffusion

Main MRI sequencesMain MRI sequencesGradient-echo (T2*)Gradient-echo (T2*)

CT PerfusionCT Perfusion

Concept of ischaemic pemumbraConcept of ischaemic pemumbra

CT PerfusionCT Perfusion

Cerebral blood volumeCerebral blood volume Cerebral blood flowCerebral blood flow

MismatchMismatch

CT PerfusionCT Perfusion

Wake up strokesWake up strokes Large strokesLarge strokes Timing questionsTiming questions MimicsMimics

FutureFuture

More CT PerfusionMore CT Perfusion More MRIMore MRI Movement towards acute arterial Movement towards acute arterial

imagingimaging

SummarySummary

Brain imaging from Stroke Physician Brain imaging from Stroke Physician perspectiveperspective

Targets – why + howTargets – why + how Where imaging may goWhere imaging may go