Post on 13-Feb-2022
16.10.2019
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Stroke Mimics
Carolina Tramontini, M.D.Neuroradiologist
Clínica Universitaria Colombia, BogotáNeuroradiology Professor
Fundación Universitaria Sanitas, Bogotá
ECNR Rovinj, October 16th, 2019
Disclosure: I have nothing to disclose
Stroke Mimics
• Introduction
• Topographic distribution patterns
• Imaging approach in stroke mimics
• Take home messages
Stroke Mimics
• Introduction
• Topographic distribution patterns
• Imaging approach in stroke mimics
• Take home messages
Stroke Mimics
• Stroke is a clinical diagnosis
• For the clinician it is not always an easy Dx
Introduction
Dupre et all, J Stroke Cerebrovasc Dis, 2017Boulter TJ,Schaeffer PW, Seminars in Radiology 2014
Two different types of diagnostic error
Two different types of diagnostic error
Conditions resembling strokebut are no real stroke
Conditions resembling strokebut are no real stroke
Presentations sugestinganother condition but are
stroke
Presentations sugestinganother condition but are
stroke
STROKE MIMICS STROKE CHAMELEON
• Stroke mimics in
– 9‐31% of suspected strokes
– 2.8‐17% of strokes treated with IV‐tPA
• Many different causes
• Imaging facilitates diagnosis
• But brain imaging, even DWI, are not infallible
Introduction
Kamalian S et all. Applied Radiology, 2015Hand PJ et all. Stroke, 2006Boulter TJ,Schaeffer PW, Seminars in Radiology 2014
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• Cognitive impairment
• Abnormal signs in othersystems
• Loss of consciousness orseizures at onset
• Complete abscence of neurological signs
Predictor for Stroke and Mimics
• Exact time of onset
• Definite focal symptoms
• Abnormal vascular findings
• Presence of neurological signs
• Being able to lateralize the signsto left or right side of the brain
• Being able to determine a clinical stroke subclassification
StrokepredictorsStroke
predictorsMimic
predictorsMimic
predictors
Hand PJ et all. Stroke, 2006Liberman AL, Prabhakaran S. Curr Neurol Neurosci Rep 2017
Most frequent causes are:
Causes of stroke Mimics
Kamalian S et all. Applied Radiology, 2015Hand PJ et all. Stroke, 2006.
21%‐ 17%
17%‐13%
13%‐ 11%
15%‐9%
9%
SeizureSeizure
SepsisSepsis
Toxic/metabolicToxic/metabolic
Space occupying lesionsSpace occupying lesions
SyncopeSyncope
• 57% of mimics were neurological conditions
• In +18% of mimics neurological conditions were in the DDX
Causes of stroke Mimics
Hand PJ et all. Stroke, 2006.
Many had normal brainimaging
Most had abnormalbrain imaging
• 75% of mimics withneurological conditions
• 42% of mimics hadprevious stroke
• Stroke mimics account for 2 to 17% of Iv‐tPA treatedpatients
• Incidence of sICH
– Stroke mimics 0.5‐ 1%
– Confirmed stroke patients 4‐ 7.9%
• Median excess cost was approximately US$ 5400 per admission
Stroke Mimics and Thrombolysis
Daniere F et all. Journal of Neuroradiology 2014Zinkstok SM et all, Stroke 2013
“The benefit of rapid treatment with tPA likelyoutweighs the minimal risk of complications associatedwith tPA in stroke mimics”
“The benefit of rapid treatment with tPA likelyoutweighs the minimal risk of complications associatedwith tPA in stroke mimics”
Liberman AL, Prabhakaran S. Curr Neurol Neurosci Rep 2017Goyal N, Journal of Stroke and Cerebrovascular Diseases, 2015
• Introduction
• Topographic distribution patterns
• Imaging approach in stroke mimics
• Take home messages
Stroke Mimics Approach based on topographicdistribution patterns
Large artery territoryinfarction
Large artery territoryinfarction
Perforating vessel infarctionPerforating vessel infarction
Border zone patternBorder zone pattern
Hypoxic ischemicencephalopathyHypoxic ischemicencephalopathy
Ischemic white matterdisease
Ischemic white matterdisease
Central embolizationCentral embolization
Regional grey and whitematter
Regional grey and whitematter
Deep grey matter and brain stem
Deep grey matter and brain stem
Vascular watershedborder zones
Vascular watershedborder zones
Cortical and deep gray matter
Cortical and deep gray matter
White matterWhite matter
Scattered fociScattered foci
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• Regional grey and white matter
• Cortical and deep gray matter
• Deep grey matter
• White matter
• Scattered foci
• Border zone pattern
Approach based on topographicdistribution patterns
Regional grey and white matterLarge artery territory infarct
SeizuresSeizures
MigraineMigraine
Brain tumorsBrain tumors
Herpes simplex encephalitisHerpes simplex encephalitis
HypoglicemiaHypoglicemia
Transient global amnesiaTransient global amnesia
MELASMELAS
Venous infarctionsVenous infarctions
• One‐third of strokemimics are due to seizures or postictaldeficits
• Seizures may cause T2 hyperintensity and restricted diffusion
• Distinguishing features– Nonvascular distribution
– Earlier edema and gyral enhancement
– Normal or elevated perfusion
– Absence of vascular occlusion
– Sometimes simultaneous restricted cortical and elevated subcortical diffusion
Regional grey and white matterSeizures
Boulter TJ,Schaeffer PW, Seminars in Radiology 2014Milligan T et all, Seizure 2009Daniere F et all, Journal of Neuroradiology, 2014
Three patterns of diffusion restriction:
• Hypocampus: Ipsilateral to side of seizure onset
• Cortical: Hypoxia, reduced energy suply, cytotoxic edema
• Splenial: excitotoxic damage due to status epilepticus
Seizures
Milligan T et all, Seizure 2009
• Causes 5‐10% of strokemimics
• May show restricted diffusion
• Distinguishing factors– Long history of migraines
– Involvement of multiple arterial territories
– Absence of vascular occlusion
• Perfusion decreases in acute‐onset aura
• Perfusion is normal or elevated in prolonged episodes
• The lesions are usually reversible
Regional grey and white matterMigraine
But remember : 15% of strokes in patients younger than 45 years of age are due to migraineBut remember : 15% of strokes in patients younger than 45 years of age are due to migraine
Regional grey and white matterBrain tumors
• May present with acute neurologic deficits
• Low‐grade glial tumor– Mildmass effect
– Cortical involvement
– May be confused with subacute infarction
• High‐grade gliomas with hemorrhage
– Can show areas of restricted diffusion
– Heterogeneous enhancement
– Mass effect
– May be confused with subacute infarction
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Brain tumors Brain tumors
Distinguishing features
Nonvascular distributionNonvascular distribution
Lack of significant restricteddiffusion
Lack of significant restricteddiffusion
Lack of gyral enhancementLack of gyral enhancement
• Most common cause of viral encephalitis
• Predilection for the limbic system
• Restricted diffusion is observed in early stages
Irreversible neuronal damage
• Cause of restricted diffusion: glutamate excitotoxic pathway
Regional grey and white matterHerpes simplex encephalitis
Kamalian S et all. Applied Radiology, 2015Boulter TJ,Schaeffer PW, Seminars in Radiology 2014
Herpes simplex encephalitis
• Hyperintense on FLAIR images• Frequently hemorrhagic transformation• DWI shows concurrent areas with decreased
and increased diffusivity
• Can present with focal neurologic deficits
• Restricted diffusion may be seen in the cerebral cortex (occipital lobes), corona radiata and centrum semiovale
• Basal ganglia, hippocampi, internal capsules and splenium maybe involved
• Cerebellum, brain stem and hypothalamus are usually spared
Regional grey and white matterHypoglicemia
Kang, AJNR, 2010
Hypoglicemia
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Hypoglicemia
Cause of diffusion restriction:
Energy failure due to lack of glucose
Energy failure due to lack of glucose
Excitotoxic edemaExcitotoxic edema
Asymmetric cerebral bloodflow
Asymmetric cerebral bloodflow
Cortical and deep gray matterHypoxic‐ischemic encephalopathy
Wernicke’s encephalopathy Wernicke’s encephalopathy
Hepatic encephalopathyHepatic encephalopathy
Creutzfeldt‐Jakob disease Creutzfeldt‐Jakob disease
Eastern equine encephalitisEastern equine encephalitis
• In alcoholics and other malnourished patients with thiaminedeficiency
• Clinically presents with:
– Altered mental status
– Memory impairment
– Ophthalmoplegia
– Ataxia
Cortical and deep gray matterWernicke’s encephalopathy
Wernicke’s encephalopathy
Symmetric T2/FLAIR hyperintensity in :• Mammillary bodies• Hypothalami• Medial thalami• Tectal plate and periaqueductal area• Cerebral cortex may also be involved
Wernicke’s encephalopathy Wernicke’s encephalopathy
• Early stages: restricted diffusion due to cytotoxic edema• Later stages: no diffusion restriction
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• Neuropsychiatric abnormalities, potentially reversible
• In chronic and acute hepatic failure
• Clinical severity: West Haven Criteria grades 1‐4
• Diffuse cortical involvement can be reversible, but is associated
with an increased risk of permanent neurologic sequela
• Decrease in ADC values due to the excitotoxic injury and osmotic
disturbance in astrocytes due to ammonia
Cortical and deep gray matterHepatic encephalopathy
McKinney et all AJNR 2010Rovira et all AJNR 2008
Mild case: symmetric T1
hyperintensity in globus pallidus
Hepatic encephalopathy
Hepatic encephalopathy
McKinney et all AJNR 2010Rovira et all AJNR 2008
Severe case: T2 hyperintensity and restricted diffusion
in the cortex (especially the cingulate gyri and insula),
basal ganglia, and thalami
Case courtesy: Fabricio Goncalvez
Cortical and deep gray matterCreutzfeldt‐Jakob disease
• Transmissible and fatal neurodegenerative disease caused by a misfolded prion protein
• Sporadic, familiar and acquired (iatrogenic and variant) forms
• Patients present with a rapidly progressive dementia
• Involvement of the basal ganglia (symmetric)
• Involvement of the cortex (symmetric or assymetric)
• DWI is more sensitive than FLAIR orT2WI
• Decreased ADC Wada R, Kucharczyk W. Neuroimag Clin 2008Boulter TJ, Schaeffer PW. Seminars in Radiology 2014
Creutzfeldt‐Jakob disease
Sporadic CJD• EEG with period sharp wave complexes• 14‐3‐3 protein positive in CSF• sCJD has not pulvinar and hockey stick signs seen in vCJD
Deep gray matter
Perforating vessel infarction
Carbon monoxide poisoning Carbon monoxide poisoning
Osmotic demyelination syndromeOsmotic demyelination syndrome
Vigabatrin toxicity Vigabatrin toxicity
Nonketotic hyperglycemiaNonketotic hyperglycemia
Radiology Assistant.com
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• Delayed encephalopathy :
– Bilateral confluent periventricular white matterT2 hyperintensity
– Areas of restricted diffusion
• Restricted diffusion
– Acute phase : cytotoxic edema
– Delayed phase: demyelination
Deep gray matterCarbon monoxide poisoning
MildMild
Restricted diffusionGPRestricted diffusionGP
T2 hyperintenseGPT2 hyperintenseGP
SevereSevere
Basal ganglia, thalamiBasal ganglia, thalami
Cerebral cortex and wmCerebral cortex and wm
Corpus callosumCorpus callosum
Carbon monoxide poisoning
• Due to rapid correction of hyponatremia
• Can be seen with malnourishment, chronic alcoholism, hyperosmolar conditions, liver transplant
• Patients typically present with pseudobulbar palsy and spasticquadriplegia
Deep gray matterOsmotic demyelination syndrome
Osmotic demyelinationsyndrome
Osmotic demyelinationsyndrome
Central pontineCentral pontine ExtrapontineExtrapontine
• Pontine lesion : centrally located and spares the corticospinal tracts
• Extrapontine lesions : thalamus, basal ganglia, lateral geniculate body
and cerebellar white matter
• T2 hyperintensity may lag up to 2 weeks
Osmotic demyelination syndrome
• Restricted diffusion appears within the first 24 hours and
may persist up to 3 weeks
Osmotic demyelination syndrome
Howard SA et all. RadioGraphics 2009
Howard SA, RadioGraphics
IschemicWhite Matter Disease
White matter
Metronidazole toxicityMetronidazole toxicity
Metrotexate toxicityMetrotexate toxicity
Heroin induced leukoencephalopathyHeroin induced leukoencephalopathy
Multiple sclerosisMultiple sclerosis
Infectious cerebritis and abscessInfectious cerebritis and abscess
thelancet.com
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• Inflammatory demyelinating disorder
• Can present with sudden acute deficits similar to acutestroke
• Acute demyelinating lesions (2‐7 days) may show transientrestricted diffusion
• Cytotoxic edema : Excitotoxic injury to oligodendrocytes, myelin sheaths and axons
White matterMultiple sclerosis
Differentiating factors:
• Typical MRI
• Multiple periventricular, deep and juxtacorticalT2/FLAIR hyperintense lesions
• Combination of clinical features and short‐term follow‐up imaging
Multiple sclerosis
Differentiating factors:
• Typical MRI
• Multiple periventricular, deep and juxtacorticalT2/FLAIR hyperintense lesions
• Combination of clinical features and short‐term follow‐up imaging
Multiple sclerosis
Small vessel disease
Multiple sclerosis
Scattered punctate fociCentral embolism
Diffuse axonal injuryDiffuse axonal injury
Fat embolismFat embolism
MetastasesMetastases
• Disruption of axons
• Caused by rapid deceleration or rotational forces
• Severe head trauma
• Multiple foci of restricted diffusion and/or hemorrhage
• Restricted diffusion for days to weeks
Scattered punctate fociDiffuse axonal injury
• Located at gray‐white matter interface and along the cerebral white matter fiber tracts, corpus callosum and brainstem
• Differentiating features:
– Nonvascular distributions and sparing of cortex
– Presence of early hemorrhage
– Clinical context of head trauma
Diffuse axonal injury
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• Secondary to spread of fat globules that reach the systemiccirculation and lung
• Setting of a recent long bone fracture or orthopedic procedure
• Can also occur following pulmonary contusion, cardiac surgeryor liposuction
• Patients present with– Changes in the respiratory pattern
– Neurologic deficits
– Petechial rash
• Not a clear knownmechanism, toxic intermediaries proposed
Scattered punctate fociFat embolism
Kamalian S et all. Applied Radiology, 2015 Boulter TJ,Schaeffer PW, Seminars in Radiology 2014
Endothelial injury and microhemorrhages
Fat embolism
• Punctate foci of restricted diffusion in white and gray matter
• Multiple hypointense foci on SWI
• Highly cellular metastases (small cell lung carcinoma)
– Can show restricted diffusion
– May be confused with subacute central embolic infarcts
• Features favoring metastases
– Presence of vasogenic edema surrounding the larger lesions
– Ring‐pattern enhancement
– Additional sites of disease
– Absence of large infarcts due to more proximal emboli
Scattered punctate fociMetastases
Differentiating factors
• Vasogenic edema
• Ring‐pattern enhancement
• Additional sites of disease
• Absence of large infarctsdue to more proximal emboli
Metastases
Boulter TJ,Schaeffer PW, Seminars in Radiology 2014
Border zone patternBorder zone infarction
Severe carotid stenosis,Moya Moya, RCVS
Posterior reversible encephalopathy syndrome (PRES) Posterior reversible encephalopathy syndrome (PRES)
Cerebral hyperperfusion syndromeCerebral hyperperfusion syndrome
Manga et all. Radiographics 2011Radiology Assistant.com
• Posterior reversible encephalopathy syndrome
• Loss of vascular autoregulation and capillary leakage leads to vasogenic edema
• Clinical presents with headaches, cortical visual symptoms, seizures, and confusion
• Triggered by
– Hypertension
– Eclampsia/ pre‐eclampsia
– Critical medical illness
– Immunosuppressants
Border zone patternPRES
Petrovic, Radiol Clin N Am ,2011
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• T2‐FLAIR hyperintensity with elevated diffusion
• Bilateral occipital and parietal lobes
• Borderzone distribution between the anterior and middle cerebral arteries
• Restricted diffusion in 10–25% patients
• Intraparenchymal hemorrhage in 15% of cases
PRES
• Introduction
• Topographic distribution patterns
• Imaging approach in stroke mimics
• Take home messages
Stroke Mimics
Approach to MRI and CT in StrokeMimics
Regional grey and white matter
Regional grey and white matter
White matterWhite matter
Deep grey matterDeep grey matterCortical and deep
gray matterCortical and deep
gray matter
Border zonepattern
Border zonepattern
Scattered fociScattered foci
Approach to MRI and CT in StrokeMimics
Regional grey and white matter
Regional grey and white matter
White matterWhite matter
Deep grey matterDeep grey matterCortical and deep
gray matterCortical and deep
gray matter
Border zonepattern
Border zonepattern
Scattered fociScattered foci
Border zoneinfarction
Central embolismIschemicWhite Matter Disease
Perforating vessel
infarction
Hypoxic‐ischemic
encephalopathy
Large arteryterritory infarct
Approach to MRI and CT in StrokeMimics
Regional grey and white matter
Regional grey and white matter
White matterWhite matter
Deep grey matterDeep grey matterCortical and deep
gray matterCortical and deep
gray matter
Border zonepattern
Border zonepattern
Scattered fociScattered foci
Border zoneinfarction
IschemicWhite Matter Disease
Perforating vessel
infarction
Hypoxic‐ischemic
encephalopathy
Large arteryterritory infarct
Central embolism
Approach to MRI and CT in StrokeMimics
Regional grey and white matter
Regional grey and white matter
White matterWhite matter
Deep grey matterDeep grey matterCortical and deep
gray matterCortical and deep
gray matter
Border zonepattern
Border zonepattern
Scattered fociScattered foci
Border zoneinfarction
IschemicWhite Matter Disease
Perforating vessel
infarction
Hypoxic‐ischemic
encephalopathy
Large arteryterritory infarct
Posterior reversible encephalopathy syndrome (PRES) Posterior reversible encephalopathy syndrome (PRES)
Cerebral hyperperfusion syndromeCerebral hyperperfusion syndrome
Diffuse axonal injury
Fat emboli
Metastases
Metronidazole toxicityMetronidazole toxicity
Metrotexate toxicityMetrotexate toxicity
Heroin induced leukoencephalopathyHeroin induced leukoencephalopathy
Multiple sclerosisMultiple sclerosis
Infectious cerebritis and abscessInfectious cerebritis and abscess
Wernicke’s encephalopathy Wernicke’s encephalopathy
Hepatic encephalopathyHepatic encephalopathy
Creutzfeldt‐Jakob disease Creutzfeldt‐Jakob disease
Eastern equine encephalitisEastern equine encephalitis
Carbon monoxide poisoning Carbon monoxide poisoning
Osmotic myelinolysisOsmotic myelinolysis
Vigabatrin toxicity Vigabatrin toxicity
Nonketotic hyperglycemiaNonketotic hyperglycemia
SeizuresSeizures
MigraineMigraine
Brain tumorsBrain tumors
Herpes simplex encephalitisHerpes simplex encephalitis
HypoglicemiaHypoglicemia
Transient global amnesiaTransient global amnesia
MELASMELAS
Venous infarctionsVenous infarctions
Central embolism
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• Introduction
• Topographic distribution patterns
• Imaging approach in stroke mimics
• Take home messages
Stroke Mimics Take home messages
• Up to 30% of suspected strokes are strokemimics
• Most frequent causes of strokemimics are:
– Seizures, sepsis, toxic/metabolic, space occupying lesions, syncope
• Inaccurate Dx can lead to unnecessary administration of
thrombolytic therapy or delays in appropriate therapy
Take home messages
• Review the clinical records of the patients
• Have an adequate knowledge of the vascular territories and evolution of images on stroke
• Remember there are different causes of diffusion restriction
• Always keep alternate diagnoses in mind when you are lookingat the images
• Use a careful pattern based approach