On the occasion of National Epilepsy Day 2014, Dr. Rama Krishnan gave a talk titled "Integrated Diagnostics – A Unique Epilepsy Approach" at the Epilepsy Knowledge Forum in Chennai organised by Neurokrish & Trimed and Sponsored Medall.

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Integrated Diagnostics – A Unique Epilepsy Approach
DDrr.. RRaammaa KKrriisshhnnaann
Consultant Radiologist
Medall Health Care Private Limited
Chennai

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Next 20 minutes…
Basic introduction to epilepsy and the burden of disease
in society and the need for investigations.
Imaging modalities - MRI
Clinico-radiologic images.
Integrated Neuro diagnostics.

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Seizure & Epilepsy
 Seizure - Definite event of altered
cerebral function due to excessive
and abnormal electrical discharge
from brain cells.
 Greek word - epilepsia “taking hold
of or seizing”
 Chronic neurologic disorder
 Spontaneous recurrent seizures
First seizure ever  4% of population
Epilepsy  1% of population
Uncontrollable epi  0.4% of population
80% has epileptogenic focus
on dedicated MRI
Imaging can be normal
Fever, drugs, dehydration & sleep deprivation

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Is investigation really needed?
What is the most effective method?

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 50 million sufferers in the world today, 85% of
whom live in the developing countries
 2.4 million new cases each year
 50% cases begin in childhood/adolescents
 70-80% of people with epilepsy could lead
normal lives if properly diagnosed and treated

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Impact to society
 Physical hazards due to
unpredictability of seizures
 Social exclusion because of
negative attitudes of others
towards epilepsy
 20-30 % of people with
epilepsy and physically able
to work are unemployed

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How is epilepsy
treated?
Long term pharmacotherapy -
Drugs
Neurosurgery – when removal
of epileptogenic focus is
possible without unacceptable
neurologic deficit
Uncontrollable epi  0.4% of population
80% has epileptogenic focus
on dedicated MRI
Lesion resection can lead to seizure freedom in many patients

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Role of neuroimaging
To identify underlying structural abnormalities
that require specific treatment
Determine functional areas
To aid in formulating a syndromic or etiologic
diagnosis

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Modalities of neuroimaging
Structural Functional
CT f MRI
MRI MRS
MEG
SPECT
PET

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CT
Emergency settings
(status epilepticus )
Calcification-Sturge
-Weber
Useful as a screening
tool
SOL and granulomas

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CT – PITFALLS
Sensitivity not more than 30%
Poor resolution in the temporal fossa – not helpful
in the diagnosis of MTS
Fails to detect abnormalities upto 50% of patients

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ILAE RECOMMENDATIONS
CT can be the diagnostic
imaging of choice in
patients with epilepsy if
MRI is not available
Patients who have
intractable seizures
should have an MRI
study even if CT is
normal

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MRI
 Imaging procedure of choice
 Identifies and localizes structural
abnormalities like MTS
 Surgical planning
 Covers both anatomic and
physiologic aspects
 Post-operative imaging

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Epilepsy Protocol MRI
(Medall)
 1.5 T magnet
 Axial, coronal and sagittal
 T1 and T2 weighted images
 FLAIR
 Oblique coronal perpendicular to the long axis of hippocampus
 3D Isotropic T1 sequence
 Susceptibility weighted imaging
 Spectroscopy if needed
 Contrast if needed

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PATHOLOGIC SUBSTRATES
Hippocampal sclerosis
Malformations of cortical
development
Neoplasms
Vascular malformations
Gliosis & miscellaneous
abnormalities

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Hippocampal sclerosis
 Complex partial seizures –
MC cause in adults
 Most common entity in pts
undergoing surgery
 H/o complicated childhood
febrile seizures, complicated
delivery and developmental
process
Surgical removal of visible MRI changes associated with
unilateral mesial temporal sclerosis leads to seizure freedom in
up to 80% of cases.

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HS
Hyperintense signal
on T2WI
Atrophy
Loss of internal
architecture
FLAIR
T2

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MR Hippocampal Volumetry
 Visual analysis – 80-90%
accuracy
 Volumetric analysis – 90-95%
 B/l HS without visually
appreciable signal changes

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Epilepsy associated tumors
Ganglioglioma – MC tumor of
temporal lobe epilepsy
DNET
Pleomorphic xanthoastrocytoma
Hypothalamic hamartoma
MR has 100% sensitivity

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Ganglioglioma
Cyst with
enhancing mural
nodule.
Calcification –
common –
distinguishing
factor.
Mural nodule

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Vascular malformations
AVM
Cavernous angioma
MR has 100% sensitivity

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AVM
-Ischemia from steal phenomenon.
-Gliosis and hemosiderin deposition
due to subclinical hemorrhages

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Cavernoma
Popcorn ball
appearance with
complete hemosiderin
rim.
Blooms on GRE.

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a b n o r m a l n e u r o n a l
p r o l i f e r a t i o n
a b n o r m a l n e u r o n a l
m i g r a t i o n
a b n o r m a l n e u r o n a l
o r g a n i z a t i o n
d e v e l o p m e n t a l
a b n o r m a l i t i e s

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Focal cortical dysplasia
Cortical or subcortical
hyperintensities
Blurred interface between
grey and white matter
Transmantle sign

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Malformations of cortical development
Agyria / pachygyria Heterotopia
Lissencephaly
Schizencephaly

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Gliosis
Focal – trauma,
infection, infarction
Diffuse – Rasmussen’s
encephalitis, sturge
weber syndrome,
perinatal insults
Encephalomalacia with
Porencephalic cyst

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Tuberous sclerosis
Epilepsy, adenoma sebaceum, mental retardation
Cortical hamartomas
Subependymal tubers
Subependymal GCA
White matter abnormalities

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DTI With Fiber
Tractography
AXIAL T2
AXIAL FT IMAGE
Decreased fiber connections

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MR Spectroscopy = Chemical
Choline peak
Lipid peak
TB
Glioma

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Functional MRI (fMRI)
 Demonstrates alterations in blood oxygenation
 Before cranial surgery to map with high accuracy functional areas
such as language, motor, and visual cortices
Speech paradigm
Astrocytoma

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Nuclear medicine imaging in epilepsy
 Perfusion changes, metabolic
changes and neurotransmission
abnormalities.
 Ictal spect and Inter-ictal PET.
 PET  lateralizion and localization in
cases of non-lesional epilepsy, in
cases of multiple lesions visible on
MRI and can guide intracranial
electrode placement.
Ictal
Inter-ictal

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PET MRI
MRI = Anatomy
PET = Function

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Lab tests
 Metabolic and genetic
abnormalities may manifest
as seizures without any
structural abnormality.
 MRI = Normal in early
infection.
 CBC and the blood chemistry
panel.

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Complete
blood count
 Infections
 Allergies
 Other abnormalities that may affect
the choice of appropriate
anticonvulsant drugs
 Help monitor the possible drug-induced
side effects in the future.

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Chemistry
panel
Sodium, potassium,
and blood sugar
levels.
RFT & LFT =
Complete metabolic
panel.

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Integrated Neuro diagnostics
EEG MRI LAB

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to conclude…
MRI is excellent tool for imaging and for surgical
planning.
Integrated neurodiagnostic approach is the most
efficient method for evaluating patients with
epilepsy.

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