Morphometric MRI features are associated with surgical outcome in mesial temporal lobe epilepsy with hippocampal sclerosis.
Corticoamygdalohippocampectomy (CAH) improves seizure control, quality of life, and decreases mortality for refractory mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). One-third of patients continue having seizures, and it is pivotal to determine structural abnormalities that might influence the postoperative outcome. Studies indicate that nonhippocampal regions may play a role in the epileptogenic network in MTLE-HS and could generate seizures postoperatively. The aim of this study is to analyze areas of atrophy, not always detected on routine MRI, comparing patients who became seizure free (SF) with those non seizure free (NSF) after CAH, in an attempt to establish possible predictors of surgical outcome.



105 patients with refractory MTLE-HS submitted to CAH (59 left MTLE; 46 males) and 47 controls were enrolled. FreeSurfer was performed for cortical thickness and volume estimation comparing patients to controls and SF versus NSF patients. The final sample after post processing procedures resulted in 99 patients.



Cortical thickness analyses showed reductions in left insula in NSF patients compared to those SF. Significant volume reductions in SF patients were present in bilateral thalami, hippocampi and pars opercularis, left parahippocampal gyrus and right temporal pole. In NSF patients reductions were present bilaterally in thalami, hippocampi, entorhinal cortices, superior frontal and supramarginal gyri; on the left: superior and middle temporal gyri, temporal pole, parahippocampal gyrus, pars opercularis and middle frontal gyrus; and on the right: precentral, superior, middle and inferior temporal gyri. Comparison between SF and NSF patients showed ipsilateral gray matter reductions in the right entorhinal cortex (p=0.003) and contralateral parahippocampal gyrus (p=0.05) in right MTLE-HS. Patients NSF had a longer duration of epilepsy than those SF (p=0.028).



NSF patients exhibited more extensive areas of atrophy than SF ones. As entorhinal cortex and parahippocampal gyrus are reduced in NSF patients compared to those SF these structures might be implicated in the network responsible for the maintenance of postoperative seizures. Duration of epilepsy is a predictor of seizure outcome.
Unidade de Pesquisa e Tratamento das Epilepsias, Department of Neurology and Neurosurgery of Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 650, Vila Clementino, CEP 04039-002, São Paulo, SP, Brazil. Electronic address: teresafcgarcia@gmail.com.
Maria Teresa Fernandes Castilho
MTFC
Garcia
Unidade de Pesquisa e Tratamento das Epilepsias, Department of Neurology and Neurosurgery of Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 650, Vila Clementino, CEP 04039-002, São Paulo, SP, Brazil.
Larissa Botelho
LB
Gaça
Department of Diagnostic Imaging of Universidade Federal de São Paulo (UNIFESP), Rua Napoleão de Barros, 800, Vila Clementino, CEP 04024-002, São Paulo, SP, Brazil.
Gabriel Barbosa
GB
Sandim
Department of Psychiatry of Universidade Federal de São Paulo (UNIFESP), Rua Borges Lagoa, 570, Vila Clementino, CEP 04038-0001, São Paulo, SP, Brazil.
Idaiane Batista
IB
Assunção Leme
Department of Diagnostic Imaging of Universidade Federal de São Paulo (UNIFESP), Rua Napoleão de Barros, 800, Vila Clementino, CEP 04024-002, São Paulo, SP, Brazil.
Henrique
H
Carrete
Unidade de Pesquisa e Tratamento das Epilepsias, Department of Neurology and Neurosurgery of Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 650, Vila Clementino, CEP 04039-002, São Paulo, SP, Brazil.
Ricardo Silva
RS
Centeno
Department of Mathematics, Computation and Cognition of Universidade do ABC, Avenida dos Estados, 5001, CEP 09210-580, São Paulo, SP, Brazil.
João Ricardo
JR
Sato
Unidade de Pesquisa e Tratamento das Epilepsias, Department of Neurology and Neurosurgery of Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 650, Vila Clementino, CEP 04039-002, São Paulo, SP, Brazil.
Elza Márcia Targas
EMT
Yacubian
D000293:Adolescent; D000328:Adult; D001284:Atrophy / Q000473:pathology; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology / Q000601:surgery; D005260:Female; D066128:Gray Matter / Q000473:pathology / Q000601:surgery; D006624:Hippocampus / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012598:Sclerosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D013702:Temporal Lobe / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
Hippocampal sclerosis; MRI morphometric analyses; Mesial temporal lobe epilepsy; Surgical outcome