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Patterns of hippocampal abnormalities in malformations of cortical development
  1. M A Montenegro1,
  2. D Kinay3,
  3. F Cendes1,
  4. A Bernasconi3,
  5. N Bernasconi3,
  6. A C Coan1,
  7. L M Li1,
  8. M M Guerreiro1,
  9. C A M Guerreiro1,
  10. I Lopes-Cendes2,
  11. E Andermann3,
  12. F Dubeau3,
  13. F Andermann3
  1. 1Department of Neurology, University of Campinas/FCM–UNICAMP, Campinas, SP, Brazil
  2. 2Department of Medical Genetics, University of Campinas/FCM–UNICAMP, Campinas, SP, Brazil
  3. 3Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
  1. Correspondence to:
 Dr F Cendes
 Department of Neurology, University of Campinas, UNICAMP, Campinas, SP, Brazil; 13083-970, PO Box 6111; fcendes{at}unicamp.br

Abstract

Objective: To assess whether different types of malformation of cortical development (MCD) are associated with specific patterns of hippocampal abnormalities.

Methods: A total of 122 consecutive patients with MRI diagnosis of MCD (53 males, age range 1–58 years) were included in the study. Hippocampal measurements were made on 1–3 mm coronal T1-weighted MRIs and compared with MRIs of normal controls.

Results: A total of 39 patients had focal cortical dysplasia, 5 had hemimegalencephaly, 5 had lissencephaly-agyria-pachygyria, 11 had SLH, 11 had PNH, 12 had bilateral contiguous PNH, 5 had schizencephaly, and 34 had polymicrogyria. The frequency of hippocampal abnormalities in these patients with MCD was 29.5%. A small hippocampus was present in all types of MCD. Only patients with lissencephaly and SLH had an enlarged hippocampus. Abnormalities in hippocampal rotation and shape were present in all types of MCD; however, these predominated in PNH. None of the patients with lissencephaly-agyria-pachygyria or SLH had hyperintense signal on T2 or FLAIR images or abnormal hippocampal internal architecture.

Conclusion: A small hippocampus was present in all types of MCD; however, the classic MRI characteristics of hippocampal sclerosis were often lacking. Abnormal enlargement of the hippocampus was associated with only diffuse MCD due to abnormal neuronal migration (lissencephaly-agyria-pachygyria and SLH).

  • FLAIR, fluid attenuated inversion recovery
  • MCD, malformation of cortical development
  • MRI, magnetic resonance imaging
  • PNH, periventricular nodular heterotopia
  • SLH, subcortical laminar heterotopia
  • cortical dysgenesis
  • hippocampus
  • magnetic resonance imaging
  • malformations of cortical development
  • volumetric measurements

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Footnotes

  • Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), São Paulo, Brazil (grant no. 97/07584-3 to Dr Cendes, and 00/04710-2 to Dr Li). Dr Montenegro received a scholarship from FAPESP (grant no. 00/03502-7). Dr Kinay received a scholarship from the Savoy Foundation for Epilepsy Research, Montreal, Quebec, Canada.

  • Competing interests: none declared

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