Hippocampal sclerosis in temporal lobe epilepsy demonstrated by magnetic resonance imaging

Abstract

The value of magnetic resonance imaging in the detection of hippocampal sclerosis has been controversial. We studied 10 patients aged 22.5 +/- 6.0 years with intractable temporal lobe epilepsy selected because of a history of a prolonged childhood convulsion, which is characteristic of a group of patients in whom hippocampal sclerosis is a constant finding. All 10 patients showed reduction in size of one hippocampus associated with increased signal intensity on T2-weighted magnetic resonance images. These changes were reliably detected on coronal spin-echo images, perpendicular to the long axis of the hippocampus. Appreciation of the normal imaging anatomy of the hippocampus allowed correct interpretation of the relative changes in signal intensities of the hippocampus and adjacent temporal horn on sequential echo images. The side of the abnormal hippocampus on magnetic resonance imaging accorded with the electroencephalographic localization in all 10 patients, and with the lateralization of the early convulsions in all 6 patients where this was known. Temporal lobectomy was performed in all 10 patients. Hippocampal sclerosis was confirmed in the 3 patients in whom hippocampal tissue was available for histological examination. The value of this technique was reinforced by the excellent postoperative results, with 80% being seizure free at a mean follow-up time of 33 +/- 4 months.

Machine learning classification of mesial temporal sclerosis in epilepsy patients

“…The pathologic finding of MTS exists in up to 65% of cases of TLE (Babb et al, 1984). MTS is characterized histologically by cellular loss and hippocampal reorganization and is often identified on MRI by hippocampal atrophy and signal abnormalities (Berkovic et al, 1991).…”

3T MRI Quantification of Hippocampal Volume and Signal in Mesial Temporal Lobe Epilepsy Improves Detection of Hippocampal Sclerosis

“…The histopathology of HS is characterized by loss of specific neurons and synaptic reorganization of surviving cells, 5 and in MR images, this is observed as volume reduction and signal hyperintensity in T2 images. 6,7 Quantification of hippocampal volume has advantages over visual analysis for the detection of subtle and bilateral hippocampal abnormalities. 2,8 Equally, the quantification of hippocampal T2 signal, especially with relaxometry, can improve the MR imaging diagnosis of HS.…”

Transcortical Selective Amygdalohippocampectomy in Temporal Lobe Epilepsy

“…24 Many of the characteristic changes described by the pathologists, particularly mesial temporal sclerosis and hippocampal atrophy, are routinely shown by MRI. 36 Furthermore, MRI can reveal a variety of additional epileptogenic lesions such as gliomas, vascular malformations, and cortical dysplasias. Atrophic changes and volumetric assessments of these changes for specific structures can now be documented accurately with MRI.…”

“…36 The syndrome of mesio-temporal lobe epilepsy has been reviewed recently by Wieser et al 37 The role of febrile convulsions in the pathogenesis of temporal epilepsy was stressed by Falconer 38 and more recently by Abou-Kalil 39 and Berkovic. 36 It is fair to say that the clinical manifestations of mesio-temporal epilepsy are, in large part, the same as those characteristics of "temporal lobe epilepsy", namely the presence of an aura, most often a hard to describe sensation, the alteration of consciousness with oral and manual automatisms, followed by amnesia for the episode. Finally, the studies of Wieser and Yasargil have shown that selective amygdalohippocampectomy (AHC) can provide results comparable to those of more traditional temporal resections.…”