Kathleen R. Fink, MD Virginia Mason Medical Center · Kathleen R. Fink, MD Virginia Mason Medical...
Transcript of Kathleen R. Fink, MD Virginia Mason Medical Center · Kathleen R. Fink, MD Virginia Mason Medical...
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Kathleen R. Fink, MD
Virginia Mason Medical Center
6th Nordic Emergency Radiology Course 2017
+ Disclosure
My spouse receives research salary support from:
Guerbet
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+ Outline
Indications for imaging
CNS infections
Extra axial
Parenchymal
Vascular complications
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+ Indications for Imaging
Suspected infection and:
Altered mental status
Seizures
Focal neurologic deficits
Immunocompromised patient with:
New headache
Any concerning sign
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+ Imaging strategy
Non contrast head CT first choice
Rapid and widely available
Well tolerated by critically ill
patients
Exclude life threatening
conditions
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Contrast enhanced MR More sensitive for subtle
findings - Leptomeningitis - Ventriculitis - Empyema - Infarction Consider strongly for
immunocompromised patients Can be problematic in sick
patients
Contrast enhanced head CT if: MR not immediately available Contraindications to MR
+ Imaging before LP?
Noncontrast CT can exclude contraindications
CT more likely to show a contraindication in patient with
(suspected meningitis) and:
• Age ≥ 60
• Immunocompromise
• Recent seizure
• Focal neurological deficit
• Impaired consciousness
Hasbun 2001 N Engl J Med 345:24, 1727-33 5/10/2017 KRF CNS infxn
+ Not safe to LP
Cerebral edema: •Poor gray-white differentiation
•Effaced sulci
•Effaced cisterns
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+ Contraindications to LP
No absolute consensus on imaging contraindications.
General agreement on the following:
Midline shift
Effacement of the basal cisterns
Posterior fossa mass effect.
Clinical signs of herniation even with normal imaging.
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+ Cautionary tale
4 PM, comatose 8 PM, after LP 5/10/2017 KRF CNS infxn
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Extraaxial
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+ 8 year old boy, sick one week
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+ 8 year old boy, sick one week
Post contrast
Acute bacterial meningitis
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+ Imaging in meningitis
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CSF evaluation is diagnostic
Goal of imaging:
1) Exclude unexpected finding
2) Evaluate for complications:
- Infarction
- Hydrocephalus
- Ventriculitis
- Subdural effusions (kids), empyema
- Venous sinus thrombosis
+ Meningitis: Imaging
Imaging Findings:
NORMAL
Especially early
Leptomeningeal enhancement
• Hemispheric
• Basilar
• Subdural effusions (especially
children)
Ddx leptomeningeal
enhancement:
Leptomeningeal
spread of tumor
Neurosarcoidosis
CNS lymphoma
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+ MRI: index case
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T1 FLAIR
DWI/ADC
+ Meningitis: MRI
Imaging Findings:
FLAIR: high signal in
subarachnoid space due to
elevated protein
May see arterial narrowing due
to infectious arteritis with or
without infarction
Ddx: Subarachnoid FLAIR hyperintensities:
Subarachnoid hemorrhage
High inspired O2
Motion artifact
Altered perfusion/blood brain barrier
disruption
Leakage of gad (renal failure, eg)
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+ 19 yo with worsening headache, nausea, and
vomiting.
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Hydrocephalus!! NECT
+ MRI
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FLAIR
DWI/ADC
+ Tuberculous meningitis
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Basilar meningitis:
Can present with
hydrocephalus due to thick
inflammatory exudate
Intracranial tuberculoma
Granulomatous lesions
Caseating or noncaseating
+/- necrotic center
Tuberculous abscess
Complications:
Vasculitis, infarcts
Patkar 2012. Neuroimaging Clin N Am 22:4, 677-705
+ Key Imaging Features
CT
Normal
Hydrocephalus
Isodense exudate in basilar cisterns
MR
Enhancing basilar leptomeninges
Infarcts
Tuberculomas: Solid, nodular or ring enhancement
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+ Image Gallery
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T1 post
DWI
Complications:
Infarcts
+
T1 pre
Basilar meningitis
Ddx: basilar meningitis:
Tuberculous meningitis
Pyogenic meningitis
Fungal meningitis
Neurosarcoidosis
Meningeal carcinomatosis
T1 post
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+ Tuberculous meningitis
Basilar meningitis
+ infarcts: TB meningitis
Fungal meningitis, including
coccidioidomycosis
Basilar meningitis + parenchymal
lesions Think TB.
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+ 53 year old man with recurrent facial cellulitis,
treated with antibiotics.
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+ Subdural empyema
ADC
T1 Post
T1 T2
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+ Subdural empyema:
CT: Isodense collection
MRI:
• T1 isointense (i.e proteinaceous
material)
• T2 hyperintense
• +/- restricted diffusion (dark ADC)
• Peripheral and meningeal
enhancement
• May see underlying cerebritis (as in
this case)
Subdural empyema, DDX:
Chronic Subdural hematoma
Subdural effusion (sterile CSF
collection associated with
meningitis)
Subdural hygroma
Dural based mets
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+ Epidural abscess
Usually associated with head and
neck infection:
Sinusitis
Otomastoiditis
Post trauma
Post Surgery
*
+
Subdural empyema and
Epidural abscess can occur
together.
MRI may help differentiate.
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+
Parenchymal
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+ History: Feeling poorly for 3 weeks, bizarre
behavior x 1 day, seizure
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+ History: Feeling poorly for 3 weeks, bizarre
behavior x 1 day, seizure
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FLAIR
+ Herpes Encephalitis
Location:
Anterior and medial temporal
lobes
Insula
Lateral temporal lobes
Inferior frontal lobes
Cingulate
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+ Key imaging features
Normal -OR-
Edema (low density)
Hemorrhage
Petechial
Along brain surface
Burned out:
Gliosis
Restricted diffusion may be
first
FLAIR
GRE for
microhemorrhages
May enhance
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CT MRI
Tien et al 1993. AJR Am J Roentgenol 161:1, 167-76
+ Image gallery
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NECT
FLAIR
DWI
+ Chronic changes of HSV encephalitis
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+ Differential diagnosis:
Ischemia (including venous infarction)
Neoplasm
Limbic encephalitis
Other viral encephalitis (e.g. arboviral)
Favor HSV:
Bilateral
Nonvascular distribution
Normal basal ganglia
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+ Arbovirus infection
Pathogenic viruses: Eastern equine
Western Equine
West Nile
Japanese
Tick-borne
Basal ganglia and thalami
lesions
T2, FLAIR, DWI
Ddx deep white matter: Anoxic/hypoxic injury
CO2, toxic exposures
Metabolic disorders (eg Wilson’s
disease)
Mitochondrial diseases
Creutzfeldt Jacob Eastern equine encephalitis.
Case courtesy of Mahmoud Mossa-Basha, MD 5/10/2017 KRF CNS infxn
+ History: 39 year old who fell
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Current Study Comparison from 9 months prior
+
MRI
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+ HIV-associated neurocognitive disorders (HAND)
Direct result of HIV on CNS
Findings on CT and MRI do not
predict cognitive dysfunction
CT:
Normal
Volume loss: sulcal or
ventricular enlargement
Patchy white matter
hypodensities
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+ HIV-associated neurocognitive disorders (HAND)
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MRI:
Symmetric white matter
disease
May resemble age-related
volume loss or white matter
lesions of vascular origin,
but more than expected for
age
Spares Juxtacortical u-
fibers
+ HIV-associated neurocognitive disorders (HAND)
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FLAIR T2
+ Key Imaging Features: HIV
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T1: occult DWI T1 post:
Non-enhancing
+ Differential Diagnosis
Age-related volume loss; white matter lesions of presumed
vascular origin (chronic ischemic change)
Hydrocephalus
Progressive multifocal leukoencephalopathy
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+ History: 43 year old with HIV and low CD4 count
who presents with gait disturbance
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T1 T1 post
T2 DWI
+ Progressive Multifocal Leukoencephalopathy
PML
Seen in certain clinical
scenarios:
HIV
Severe
immunosuppression
Multiple sclerosis on
natalizumab
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+ PML
Imaging findings
Low density CT and T2
hyperintense areas
Little mass effect or
contrast enhancement
Parietal, occipital lobes
Asymmetric
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+ Features favoring a diagnosis of PML over
HIV
Involvement of
subcortical u-
fibers
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PML HIV
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Sahraian. European Journal of Neurology 2012, 19: 1060–1069 doi:10.1111/j.1468-
1331.2011.03597.x
PML HIV
Confluent lesions, favors parieto-
occipital or CC
Normal or patchy periventricular
centrum semiovale lesions
Involves juxtacortical U fibers Spares U fibers
Asymmetric Symmetric
Low on T1 Usually isointense on T1
Low on DWI unless active
demyelination Isointense on DWI
Does not enhance unless IRIS
(immune reconstitution
inflammatory syndrome)
No enhancement
+ Image Gallery
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Posterior fossa involvement
+ Image Gallery
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T2
NECT
T1 post
DWI
ADC
PML IRIS
+ History: 33 year old with nausea, vomiting
and right sided weakness
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+ Neurocysticercosis
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Taenia solium, pork tapeworm
Cyst with central dot
Central dot is scolex
Four pathologic stages: Simple
cyst complex cystic lesion
calcification
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Stage CT Findings MR Findings
Noncystic (Active asymptomatic)
Normal Normal
Vesicular (Cyst or cluster of cysts
with scolex)
1-2 cm cyst Simple appearing fluid
No edema. Scolex
Thin-walled cyst Follows CSF
Little enhancement. Scolex
Colloidal vesicular (Larva degenerates,
inflammatory response begins)
Cyst may be dense Enhances ± Edema
Proteinaceous cyst Thick walled
Edema Enhancement
Granular nodular (Cyst retracts and
granulomatous reaction ensues)
Edema increases. Thick ring enhancement
Edema increases. Thick ring enhancement
Calcified nodular (Inactive)
Calcific nodules without edema or enhancement
Hypointense nodules without edema or
enhancement Kimura-Hayama Radiographics 2010 Oct;30(6):1705-19.
doi: 10.1148/rg.306105522.
+ Key Imaging Features
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T2
NECT
T1 post
DWI
ADC
+ Image Gallery
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Subarachnoid
Intraventricular cysts can cause
hydrocephalus.
Calcified nodular phase
+ Differential Diagnosis
Pyogenic abscess (no scolex)
Ring enhancing mass:
Metastasis
Glioblastoma multiforme
Lymphoma in immunocompromised patient
Etc.
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+ History: 38 year old with recurrent sinus infections,
worsening headache, nausea and vomiting
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+ Contrast
+ MRI:
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FLAIR
T1
T1 post
DWI
ADC
+ Pyogenic abscess
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Focal pus collection with
surrounding capsule.
Direct extension
Sinusitis
Otomastoiditis
Odontogenic
Hematogenous
IVDA
Endocarditis
Pulmonary AVF
+ Pyogenic abscess
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Parenchymal mass
Gray-white junction
Low T2 ring
Hyperintense necrotic core
Rim enhancement
• Thick smooth
• Thinned medial wall
Restricted diffusion of central
necrotic core
Daughter cells
Look for ventricular extension
+
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Image gallery
+ Cerebritis
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2 days later
DWI
T1 post
FLAIR
FLAIR
T1 post
+ Abscess development
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13 days later
Early cerebritis
Ill defined edema
Late cerebritis
Central low density
Early capsule
Thin rim enhancement
Late capsule
Thick rim enhancement Britt J Neurosurg 1983 December;59(6):972-89.
+ History: 40 yo with HIV and 2 days of
headache, blurry vision, gait disturbance
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+ MRI: Vital in Immunocompromised
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+ Toxoplasmosis
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Toxoplasma gondii
Reactivation of latent infection in immunocompromised patient
Masses:
Ring enhancing
T2 heterogeneous
No restricted DWI of central necrotic portion
Location:
Basal ganglia
Thalamus
Gray-white junction
Akgoz et al. Neuroimaging Clin N Am 22:4, 633-57
Eccentric target sign:
Specific not sensitive
+ HIV patient with mental status change
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FLAIR
DWI
ADC
+ Cryptococcus
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Cryptococcus neoformans
Associated with HIV infections
Can affect immunocompetent
patients
Presents as
Meningitis
Meningoencephalitis
Cerebral vasculitis
Imaging may be normal.
+ Cryptococcus
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Imaging patterns:
• Meningeal enhancement
• Basilar meningitis
Masses: cryptococcomas
Granulomas
Basal ganglia predominant
May enhance (immunocompetent)
Choroid plexus
Gelatinous exudate:
• Dilated perivascular spaces
• Pseudocysts
+ Image Gallery
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T2 T1 post
DWI
ADC
FLAIR T1
+ Image gallery: C. gatti
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Dilated VR spaces Cryptococcomas of choroid plexus
+ Differential Diagnosis
Tuberculous meningitis
Cryptococcus meningitis
Coccidioidal meningitis
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+
Vascular complications
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+ 54 yo, aortic valve replacement, new headache
NECT CTA 5/10/2017 KRF CNS infxn
+ Conventional Angiogram
2 months prior Current
Right ICA injection 5/10/2017 KRF CNS infxn
+ Mycotic aneurysm
New peripheral (distal MCA)
aneurysm
Unusual location for saccular
aneurysm
Treatment is resection
* methicillin-sensitive staphylococcus aureus
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+ Infectious vasculitis: S. pneumo meningitis
Initial T2 2 wks later
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+ Septic emboli
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+ Outline
Indications for imaging
CNS infections
Extra axial
Parenchymal
Vascular complications
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