Download Acute Stroke Management

Introduction to MRI Head Imaging
Ryan Hakimi, DO, MS
Director, Critical Care Neurology
Assistant Professor
Department of Neurology
The University of Oklahoma Health Sciences Center
January 16, 2015
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DISCLOSURES
FINANCIAL DISCLOSURE
Nothing to disclose
UNLABELED/UNAPPROVED USES
DISCLOSURE
Nothing to disclose
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Objectives
 Describe the pros and cons of MRI versus CT when
imaging the head
 Discuss some common MRI sequences
 Illustrate the appearance of acute ischemic stroke on
various MRI head sequences
 Present MRI head imaging of other common
neurological diagnoses
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Principles of Magnetic Resonance
Imaging
Uses a magnet and radio waves to create
an image based on changes in alignment
of protons in the tissue
 Terminology
Hyperintense (bright, white)
Hypointense (dark, black)
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Advantages of MRI over CT Head
No radiation
Can image in multiple planes (axial,
sagital, coronal, oblique)
Superior soft tissue imaging
Can image some vessels without contrast
(MRA head)
Many different sequences allow for
specialized imaging
Can image the brainstem and cerebellum
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Disadvantages of MRI vs CT Head
Inferior bone imaging
Cost
Longer study time
Images degraded by motion
Can not image patient with pacemaker,
claustrophobia, metallic foreign bodies
(bullet)
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Axial T1
orbit
pons
T1 looks like a CT
CSF is black
(hypointense)
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Sagital T1
atrophy
corpus collosum
pons
cerebellum
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Coronal with contrast (gadolinium)
With contrast can see
hyperintensity of the blood
vessels
Good for visualization of
hyppocampi
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Axial T2
T2 has white
(hyperintense)CSF
lateral ventricles
frontal horn
occipital horn
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DWI brainstem
Breakdown of blood brain barrier
acute ischemic stroke
acute demyelination
acute trauma
Right
pontine
ischemic
infarction
T2 shine
through
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T2* acute ICH
(gradient echo)
Blood will appear black
(hypointense)
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Acute Ischemic Stroke
DWI
T1
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Acute Ischemic Stroke
T2
FLAIR
(fluid-attenuated inversion
recovery)
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Acute Ischemic Stroke
T2*
petechial hemorrhages
within the ischemic
tissue
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MRA (LMCA patent)

Image can be rotated, left is not always on the right side of the screen, must look at labels
anterior
cerebral
artery
middle
cerebral
artery
R
L
internal
corotid
artery
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Normal Pressure Hydrocephalus
 Central atrophy (large
ventricles) out of proportion to
peripheral atrophy (minimal
atrophy)
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Meningioma
 Extraaxial brain tumor
(outside of the brain) displacing
The brain)
Enhances with gadolinium
Has a dural tail
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Multiple Sclerosis
Periventricular white matter hyperintensities, some of which
enhance, from National MS Center
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GAD with NSF
Puts patients at risk for nephrogenic
systemic fibrosis
Fibrosis of skin, eyes, organs
Gadolinium can not be administered in
patients:
Glomerular filtration rate (GFR) of 30 or less
On dialysis
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Questions
Thank you
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