Neuro-imaging in Epilepsy 

Ehab Abou Elfotouh Elaryan. Lecture Of Radio-diagnosis.

Al-Azhar University.

Temporal lobe epilepsy:The most common epilepsy syndrome in adults.The epileptogenic focus involves the structures of

the mesial temporal lobe.These structures include the hippocampus,

amygdala, and parahippocampal gyrus.Hippocampal sclerosis is characterized by neuronal

loss and gliosis with secondary atrophy and sclerosis.The neuronal loss and gliosis occurs in all segments

of the cornu ammonis and dentate gyrus, but it is most prominent in the CA1 region with relative sparing of the CA2 segment.

The involvement is usually most prominent in the body of the hippocampus, followed by the tail and head.

Epilepsy MR Imaging Protocol:A- Axial FSE T2-Weighted.

B- Axial FLAIR.

C- Coronal SPGR, FSE T2WIs and FLAIR. ( angled perpendicular to hippocampus )

D- Post gadolinium images. ( new onset )

Epilepsy MR Imaging Protocol:T1-weighted spoiled gradient recalled

(SPGR) or magnetization prepared rapid gradient echo (MPRAGE) images 1.5-mm slice thickness with no intervening gap obtained in the coronal oblique plane. These images are acquired as a 3-dimensional (3D) volume.

Coronal and axial fluid-attenuated inversion recovery (FLAIR) sequences with a 2- to 3-mm slice thickness and a 0- to 1-mm interslice gap.

A conventional thin-slice (3-mm) T2-weighted axial and coronal sequence is also obtained.

Temporal lobe epilepsy:MRI findings of HS:

Atrophy of the hippocampus on T1-weighted SPGR (typically seen in 90-95% of cases). The atrophy is most prominent in the hippocampal body.

Bright signal is observed in the hippocampus on

T2-weighted and FLAIR studies due to increased water contents .

Temporal lobe epilepsy:Secondary findings of hippocampal sclerosis

on MRI are observed, such as :1) Enlargement of the ipsilateral temporal horn.2) Thinning of the fornix.3) Mamillary body atrophy.4) Loss of normal inter-digitations of the

hippocampal head.5) Atrophy of the collateral white matter between

the hippocampus and the collateral sulcus.

*THANKS ALL.