epilepsy

• Epilepsy is a chronic, neurologic disorder

characterized by spontaneous, recurrent

seizures.

• Seizures are caused by excessive and

abnormal electrical discharges from the

cortical neurons.

• Generalized.

• Partial.

• Identify underlying structural

abnormalities that require specific

treatment.

HippocampusHippocampus


The Hippocampal Formation Consists

Of The Hippocampus, The Dentate

Gyrus and The Subiculum.


1. Essential Role In The Formation Of

New Memories.

2. Storing And Processing Spatial Information.

• Hippocampal sclerosis is the most

common epileptogenic substrate

seen.

• Initial precipitating injury, usually

before the age of 5 years.

• Hippocampal sclerosis is

characterized by neuronal loss and

gliosis.

• Hippocampal Sclerosis.

• Mesial Temporal Sclerosis.

1. Unilateral Diffuse Hippocampal Sclerosis.

2. Unilateral Anterior Hippocampal

Sclerosis.

3. Bilateral Diffuse Hippocampal Sclerosis.

1. FLAIR.

2. T1W-IR.

3. T2W.

CORONAL

1-3 mm. Slice Thickness

CORONAL AXIAL

1. Qualitative.

2. Quantitative.

Qualitative

• Direct: Atrophy (Decreased Size) and abnormal signal.

• Indirect: Loss of internal architecture, loss of hippocampal head

interdigitations, atrophy of ipsilateral mammilary body and

fornix, dilatation of the ipsilateral temporal horn, volume loss of

the temporal lobe, atrophy of the collateral white matter

between the hippocampus and collateral sulcus and dilatation

of the “crab’s claw” of the Perihippocampal Fissures.

Qualitative

Qualitative

Atrophy And Abnormal T2 Signal

Qualitative

Quantitative

1. Hippocampal Volumetry.

2. HCT2 Measurement.

3. Diffusion-weighted Imaging

(DWI)

Quantitative1. Hippocampal Volumetry.

Quantitative

2. Hippocampal (HC) T2 Mapping.

Quantitative

3. Diffusion-Weighted Imaging

(DWI)

1. Diffuse.

2. Focal Cortical Dysplasia (FCD).

Focal developmental anomalies of cortical structure Focal developmental anomalies of cortical structure

characterized histologically by cortical dyslamination characterized histologically by cortical dyslamination

and the presence of abnormal giant neurons and the presence of abnormal giant neurons

throughout the affected cortex and adjacent white throughout the affected cortex and adjacent white

matter, accompanied in many cases by grotesquely matter, accompanied in many cases by grotesquely

shaped balloon cells of uncertain lineage.shaped balloon cells of uncertain lineage.

1.1. Disorganization of cortical layers.Disorganization of cortical layers.

2.2. Heterotpoic cortical cell within the adjacent white Heterotpoic cortical cell within the adjacent white

matter.matter.

3.3. Myelination defects in the related nerve fibres.Myelination defects in the related nerve fibres.

ClassificationClassification Characteristics

• Architectural dysplasia oHeterotopic neurons in white matteroDerangement of cortical lamination

• Cytoarchitectural dysplasia oHeterotopic neurons in white matteroDerangement of cortical laminationoGiant neurons

• Taylor’s FCD

Without balloon cells oHeterotopic neurons in white matteroDerangement of cortical laminationoGiant neuronsoDysmorphic neurons

With balloon cells oHeterotopic neurons in white matteroDerangement of cortical laminationoGiant neuronsoDysmorphic neuronsoBalloon cells

MR Imaging

Best Sequences:

3D T1 IR

3D T2 SE

FLAIR

1-2 mm slice-1-2 mm slice-

thicknessthickness

MR Imaging

MR Imaging

Focal thickening of the cortex.

Blurring of the gray matter–white matter junction.Signal

intensity changes.

MR Imaging

epilepsy

Health & Medicine

hippocampal volumetry

hippocampal formation

cortical neurons

qualitative atrophy

quantitativ e

cortical dyslamination

adjacent white matter

hippocampal hc t2 mapping