NEURORADIOLOGY MEETMAY 2016Dr.AMIT JAISWAL

PATIENT PROFILE

Age-21 yr old Sex-Female Ethinicity -Indian

HISTORY AND CLINICAL SYMPTOMS

Blurred vision and dimunition of vision in Rt eye since 3 days.

MRI FINDINGS

MULTIPLE SCLEROSIS

ETIOPATHOGENESIS Etiology ○ Unknown; probably virus &/or autoimmune-mediated in genetically susceptible individuals ○ Activated T cells attack myelinated axons ○ Cox-2, iNOS may cause excitotoxic death of oligodendrocytes • Genetics ○ Multifactorial; ↑ incidence in 1st-order relatives

DEMOGRAPHICS

Estimated 2.5 million people in world have MS Most common disabling CNS disease of young adults; 1:1,000 in Western world Age: 20-40 years Peak onset = 30yr of age; 3-5% < 15, 9% > 50 Adults: M:F = 1:2; adolescents: M:F = 1:3-5

CLINICAL PRESENTATION

• Most common signs/symptoms ○ Variable; initially impaired/double vision of acute optic neuritis (50% with positive MR develop MS) ○ Weakness, numbness, tingling, gait disturbances ○ ↓ sphincter control, blindness, paralysis, dementia ○ Cranial nerve palsy; usually multiple, 1-5% isolated (CN5,6 most common) ○ Spinal cord symptoms in 80%

TYPES Relapsing-remitting Secondary-progressive Primary-progressive Progressive-relapsing Radiologically isolated syndrome (RIS) MR findings suggestive of MS without typical MS symptoms and normal neurological exam

IMAGING PROTOCOL

IMAGING FEATURES

T1WI ○ Typically hypo- or isointense ○ Hypointensity correlates with axonal destruction ("black holes") ○ T1 hypointense lesions suggest worse prognosis Correlated with disability, atrophy, progressive disease ○ Hyperintense dentate nuclei seen in secondary

progressive form

T2WI ○ Hyperintense, linear foci radiating from ventricles ○ Also prevalent in subcortical U-fibers, brachium

pontis,brainstem, and spinal cord ○ High cortical disease burden can be predictor of

primary progressive MS ○ Hypointense basal ganglia 10-20% of chronic MS

FLAIR ○ Earliest finding: Alternating linear hyperintensity

along ependyma on sagittal FLAIR– Ependymal "dot-dash" sign

○ Bilateral, asymmetric, linear/ovoid hyperintensities ○ Perivenular extension; "Dawson fingers“--Along path

of deep medullary veins ○ Hyperintensities become confluent with severity

DWI Majority of acute plaques: Normal or↑ diffusivity Few acute MS plaques may show restricted diffusion Often at the

margins of acute plaque ○ Subacute/chronic plaques show↑ diffusivity DTI: Reduced longitudinal diffusivity in areas of axonal injury

T1WI C+ ○ Transient enhancement during active demyelination (>90%

disappear within 6 months) – Nodular (68%) or ring (23%) – Semilunar, incomplete, horseshoe-shaped (9%) – Rare: Large tumefactive enhancing rings

MRS

○ ↓ NAA (NAA/Cr), ↑ choline (Cho/Cr), ↑ myoinositol ○ MRS abnormalities found in normal-appearing white matter

(NAWM) ○ Only secondary progressive MS shows ↓ NAA in normal

appearing gray matter (NAGM)– May allow early distinction between relapsing remitting and secondary-progressive

Perfusion MR (contrast-enhanced T2*):

Low Rcbv ○ Can separate tumefactive MS from neoplasm • Magnetization transfer (MT) ○ ↓ MT ratio (MTR) in lesions/NAWM • Functional connectivity MR (fcMR) ○ ↓ functional connectivity between right/left hemisphere primary visual and motor cortices • 3.0 T vs. 1.5 T: 21% ↑ number of contrast-enhancing lesions,

30% ↑ enhancing lesion volume, 10% ↑ total lesion volume

DIFFERENTIAL DIAGNOSIS

Acute disseminated encephalomyelitis (ADEM) Neuromyelitis optica Autoimmune-mediated vasculitis CADASIL Lyme disease Susac syndrome

Acute Disseminated Encephalomyelitis (ADEM)

• Viral prodrome, monophasic illness, more common in children • Can mimic MS; gray matter often involved • ADEM lesions tend to be larger, more edematous, and

often symmetric

Neuromyelitis Optica

• Optic neuritis and spinal cord lesions extensive spinal cord lesions. lesions often involve most of the cord.

This is unlike MS, in which the lesions are usually smaller and peripherally located.

• Brain lesions look atypical for MS, tend to border midline CSF spaces

Autoimmune-Mediated Vasculitis

• Enhancing lesions spare callososeptal interface

• "Beaded" angiogram appearance

CADASIL

• Premature dementia and recurrent strokes with NOTCH3 mutations

• Tends to spare corpus callosum, subcortical U-fibers

Lyme Disease

Can be identical to MS (skin rash common)

enhancement of CN7

Susac Syndrome• Classic triad: Encephalopathy,

branch retinal artery occlusions, hearing loss

VASCULAR Vs MS

WHY MS IN THIS CASE ???

Typical for MS in this case is: Involvement of the temporal lobe Juxtacortical lesions - touching the cortex Involvement of the corpus callosum Periventricular lesions - touching the ventricles

Involvement of the temporal lobe

Juxtacortical lesions - touching the cortex

Involvement of the corpus callosum

Periventricular lesions - touching the ventricles

REVISED McDONALD’S CRITERIA

DAWSON FINGERS Ovoid lesions perpendicular to the ventricles. Dawson fingers are typical for MS and are the result of

inflammation around penetrating venules.These veins are perpendicular to the ventricular surface

SPINAL LESIONS

Best sequence-PDW Sequences. On PDW-images the spinal cord has a uniformly low signal intensity (like CSF), which gives the MS lesions a good contrast against the surrounding CSF and normal cord tissue Typical spinal cord lesions in MS are relatively small and

peripherally located. They are most often found in the cervical cord and are

usually less than 2 vertebral segments in length. A spinal cord lesion together with a lesion in the cerebellum or

brainstem is very suggestive of MS.

MS variants/subtypes

Malignant/Marburg disease: Younger patients, febrile prodrome, clinically fulminant, death in months

Schilder type ("diffuse sclerosis"): Extensive, confluent,asymmetric demyelination in bilateral supra-/infratentorial parenchyma

Baló type ("concentric sclerosis"): Large lesions with,alternating zones of demyelinated/myelinated WM

BALÓ TYPE ("CONCENTRIC SCLEROSIS")

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