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Palmetto Health Richland August 2008
35 yo AAF presents with confusion, agnosia, apraxia, right-sided lower extremity paresis
Symptoms first noticed 2 hours ago CT scan- no blood MRI- single hyperintense lesion in the left
periventricular white matter Started IV steroids, ran a panel of CSF &
blood studies 3 days later- Symptoms resolved Diagnosed with Multiple Sclerosis
The Imaging of Multiple Sclerosis* Utility of MRI* Differential of White Matter Lesions* Future direction of neuroradiology
Jessica Floyd, M4
What is Multiple Sclerosis? Chronic Inflammatory demyelinating disease of
the CNS 2nd-3rd decade of life (“belongs to the climax of
life”) 2:1 Female predominance 250-350,000 people with MS in the US Cyclical inflammatory reactions followed
by remission of symptoms and variable recovery Relapsing-Remitting- 80% Primary Progressive- 20%; closer incidence M:F Secondary Progressive
Charcot’s description
First described by Charcot in 1835 Patient history, physical exam, autopsy Salpetriere (1865) to the United States
Blood vessel at the center of each lesion Preserved axis cyllinder Atrophy of the medullary sheath Types:
Cephalic Spinal Mixed: cerebrospinal
Broad Symptom Complex Sensory disturbances Unilateral optic neuritis Diplopia- Internuclear opthalmoplegia Nystagmus Lhermitte’s sign Limb weakness Clumsiness Gait ataxia Neurogenic bladder Bowel symptoms
Symptoms
Fatigue Worse in the afternoon Physiologic increases in temperature
Post Partum worsening of Symptoms ~ 4wk
Uhthoff’s symptom- hot shower, hot bath
Pseudoexacerbations with fever
Symptoms
Highly suggestive of MS: Paroxysmal pain, paresthesias Trigeminal neuralgia Episodic clumsiness, nysarthria Tonic limb posturing
Less common: Prominent cortical signs▪ Aphasia, apraxia, recurrent seizures, visual field
loss, early dementia Extrapyramidal phenomena▪ Chorea, rigidity
WHAT DOES IT LOOK LIKE?
Brain Lesions
Most sensitive modality is MRI Sensitive to inflammation Sensitive to demyelination
CT is a poor tool unless very severe destruction
Callosal atrophy Whole brain atrophy
T2 Lesions
Inflammation (water) & Demyelination (loss of fat) Hyperintensities on T2 weighted images
Confirm with FLAIR images Round, Ovoid Vary in size. Few mm Few cm Periventricular region, corpus callosum
Perivascular distribution, penetrating venules Dawson’s fingers
Juxtacortical Lesions, U-fibers
T2 Lesions
Temporal Lobe Brainstem- peripherally Deep Gray Matter- BG, Thalamus (LC) Cerebellum Spinal Cord Recurrent Lesions in Same Area CONFLUENT
lesions MC anterior & posterior to lateral ventricle
Vasogenic edema = “fuzzy extension” of T2 signal
LARGE DIFFERENTIAL FOR T2 Hyperintensities
T2 Lesions- FLAIR
Dawson’s Fingers- Sagital FLAIR
T1 Holes
SEVERE Tissue Injury T1 dark signals
Rarely seen in the spinal cord or post fossa
Stronger correlation with demyelination & axonal loss than T2 hyperintensities
Evolution of enhancing lesions T1 Holes associated with more progressive disease
T2 lesions & T1 Holes
Gadolinium-Enhancing Lesions Indicates breakdown of the blood-brain
barrier Very active inflammation Pattern of enhancement
Homogenous Ring reactivation of an old lesion Heterogeneous
Enhancement duration varies- days, weeks 5% pts have >3 months of single lesion
enhancement
Spinal Cord Lesions
Round, Ovoid on T2 Limited to 1-2 spinal cord segments 80% involve half of cord cross sectional area
Ddx- ITM, Devic’s Dz Typically unilateral Inflammatory edema temporary cord
expansion Ddx- Tumor (bx)
Gadolinum enhancment with active BBBB Post mortem path studies show greater
demyelination than assumed with conventional t2 imaging
35 yo female- acute onset Quadriparesis
Spinal Lesions- Gad-enhancement
Brain Atrophy
Significant Clinical Implications Correlates with clinical disability Predictive of later progressive
disability Many standard therapies slow
progression of atrophy over time
Callosal Atrophy
Diagnosis
Ensuring MS is of high suspicion, consider prevalence and a priori probability
How suspicious are you? Imaging is only one part of the story, clinical picture Incidental Finding versus Manifesting Clinically
Normal Aging or Virchow Robin Spaces Vascular disease▪ Infarction▪ Multi-infarct Dementia▪ Hypertensive encephalopathy
Sarcoidosis- ACE level, pulmonary Sx, CXR SLE- discoid/malar rash, other organ involvment Lyme Disease- CN7 palsy, rash, influenza-like illness HIV- test, immunocompromised Progressive Multifocal Leukoencephalopathy-
immunocompromised Largest differential concerns Vascular versus MS
Normal Aging & Fazeka’s
Virchow Robin Spaces
Vascular vs Multiple Sclerosis
Vascular disease vs Multiple Sclerosis
66 yo Male T2 HyperintensitiesNone being OvoidFew Periventricular LesionsNo Juxtacortical lesions
Vascular vs. Multiple Sclerosis
Criteria for Diagnosis of MS
Since MRI revolutionized the diagnosis of MS, needed specific criteria
Crux of the Dx is demonstrating attacks of neurologic dysfunction are separated in space and time Clinical criteria* pt hx, PE findings, Laboratory Criteria* oligoclonal bands,
IgG index MRI * 2001 McDonald Criteria, 2005
revised
Diagnostic Criteria
Dissemination in TIME- 3 months
One episode, treat or not to treat?
Cannot diagnose MS on MRI alone- need the clinical exam & history
However, MRI can now show us what even a vigorous clinical exam cannot
Revolutionizing treatment treat earlier
Mild cognitive deficits discovered earlier
42 yo woman with MS, no Sx
Coming in the future…
MR Spectroscopy- N-acetyl aspartate, Lactate
Diffusion Tensor Imaging Able to pick up on lesions not yet
detectable on MRI Ability to give you information on
precisely how damaged the lesion is compared to other lesions
Diffusion Tensor Imaging
Diffusion Tensor Imaging
o3-D water diffusion oMean Diffusivity- overall diffusionoFractional anisotropy- amount of elongatedness of diffusionoColorized primary eigenvector maps- illustrate different directions of the primary fiber tracto RED = L-Ro GREEN = Up-Downo BLUE = In-Out of page
Gad- enhancement T1 & T2
Dawson’s fingers – T1 & T2
FLAIR & T-1 black hole
Confluent Lesions & Atrophy
Progressive Multifocal Leukoencephalopathy
Sarcoidosis
Acute Disseminated Encephalomyelitis
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