Hippocampal atrophy on MRI is predictive of histopathological patterns and surgical prognosis in mesial temporal lobe epilepsy with hippocampal sclerosis

Purpose: To correlate hippocampal volumes obtained from brain structural imaging with histopathological patterns of hippocampal sclerosis (HS), in order to predict surgical outcome. Methods: Patients with mesial temporal lobe epilepsy (MTLE) with HS were selected. Clinical data were assessed pre-operatively and surgical outcome in the first year post surgery. One block of mid hippocampal body was selected for HS classification according to ILAE criteria. NeuN-immunoreactive cell bodies were counted within hippocampal subfields, in four randomly visual fields, and cell densities were transformed into z-score values. FreeSurfer processing of 1.5 T brain structural images was used for subcortical and cortical volumetric estimation of the ipsilateral hippocampus. Univariate analysis of variance and Pearson's correlation test were applied for statistical analyses. Results: Sixty-two cases (31 female, 32 right HS) were included. ILAE type 1 HS was identified in 48 patients, type 2 in eight, type 3 in two, and four had no-HS. Better results regarding seizure control, i.e. ILAE 1, were achieved by patients with type 1 HS (58.3%). Patients with types 1 and 2 had smaller hippocampal volumes compared to those with no-HS (p<0.001 and p=0.004, respectively). Positive correlation was encountered between hippocampal volumes and CA1, CA3, CA4, and total estimated neuronal densities. CA2 was the only sector which did not correlate its neuronal density with hippocampal volume (p = 0.390). Conclusion: This is the first study correlating hippocampal volume on MRI submitted to FreeSurfer processing with ILAE patterns of HS and neuronal loss within each hippocampal subfield, a fundamental finding to anticipate surgical prognosis for patients with drug-resistant MTLE and HS. (C) 2016 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Fed Sao Paulo UNIFESP, Dept Neurol & Neurosurg, Clin Neurol Sect, Rua Pedro Toledo 650,1 Andar, BR-04039002 Sao Paulo, SP, BrazilFac Ciencias Med Santa Casa Sao Paulo, Dept Pathol Sci, Rua Dr Cesareo Mottak Jr,61 Vila Buarque, BR-01221020 Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Neurosurg Sect, Dept Neurol & Neurosurg, Rua Napoleao Barros 715,6 Andar Vila Clementino, BR-04024002 Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Diagnost Imaging Sect, Dept Diagnost Imaging, Rua Napoleao Barros 800 Vila Clementino, BR-04024002 Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Neurosci Sect, Dept Neurol & Neurosurg, Rua Pedro Toledo 669,2 Andar Vila Clementino, BR-04039032 Sao Paulo, SP, BrazilClinical Neurology Sector, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 650 – Vila Clementino, CEP 04039-002, São Paulo, SP, BrazilNeurosurgery Sector, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo (UNIFESP), Rua Napoleão de Barros, 715, 6° andar – Vila Clementino, CEP 04024-002, São Paulo, SP, BrazilDiagnostic Imaging Sector, Department of Diagnostic Imaging, Universidade Federal de São Paulo (UNIFESP), Rua Napoleão de Barros, 800 – Vila Clementino, CEP 04024-002, São Paulo, SP, BrazilNeuroscience Sector, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 2° andar – Vila Clementino, CEP 04039-032, São Paulo, SP, BrazilWeb of Scienc