ou neurology introduction to mri head imaging ryan hakimi, do, ms director, critical care neurology...

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Introduction to MRI Head Imaging

Ryan Hakimi, DO, MSDirector, Critical Care Neurology

Assistant ProfessorDepartment of Neurology

The University of Oklahoma Health Sciences CenterJanuary 16, 2015

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DISCLOSURES

FINANCIAL DISCLOSURENothing to disclose

UNLABELED/UNAPPROVED USES DISCLOSURENothing 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

TerminologyHyperintense (bright, white)Hypointense (dark, black)

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Advantages of MRI over CT Head

No radiationCan image in multiple planes (axial, sagital,

coronal, oblique)Superior soft tissue imagingCan image some vessels without contrast

(MRA head)Many different sequences allow for

specialized imagingCan image the brainstem and cerebellum

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Disadvantages of MRI vs CT Head

Inferior bone imagingCostLonger study timeImages degraded by motionCan not image patient with pacemaker,

claustrophobia, metallic foreign bodies (bullet)

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Axial T1

T1 looks like a CT

CSF is black

(hypointense)

orbit

pons

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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 ventriclesfrontal 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 StrokeDWI T1

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Acute Ischemic StrokeT2 FLAIR (fluid-attenuated inversion

recovery)

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Acute Ischemic StrokeT2*

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

L R

internal corotid artery

anterior cerebral artery

middle cerebral 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 fibrosisFibrosis of skin, eyes, organs

Gadolinium can not be administered in patients:Glomerular filtration rate (GFR) of 30 or lessOn dialysis

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Questions

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Thank you