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Neuroimaging Evaluation in Neocortical Epilepsies

  • N. Colombo
  • N. Bargalló
  • D. Redaelli
Living reference work entry

Abstract

Neocortical epilepsy is a chronic condition characterized by focal or generalized seizures starting within the cortex of any lobe of the brain. In this chapter, some of the most common epileptogenic lesions will be discussed, including malformations of cortical development (MCDs) comprising focal cortical dysplasia (FCD), polymicrogyria (PMG), heterotopia (HTP), hemimegalencephaly (HME), and acquired lesions after vascular and traumatic injuries that can develop to post-stroke epilepsy (PSE) or post-traumatic epilepsy (PTE). Some other lesions like cortical tubers of tuberous sclerosis complex and cavernous angioma, which can be associated to neocortical epilepsy, are treated in other chapters of this book. Clinical neuroradiology plays a pivotal role to establish the diagnosis and to select patient candidate to surgery. The radiological technique fundamental for neocortical epilepsies is brain magnetic resonance imaging (MRI). It is mandatory in patients with drug-resistant focal epilepsy (DRFE) aimed to detect the suspected associated anatomical lesion and to define its location, extension, and relationship with the eloquent brain areas.

An epilepsy-specific protocol is needed to identify even very subtle lesions, particularly tiny FCDs. Knowledge of the electro-clinical presentation is key for planning a correct MRI examination to use the proper sequence angulation. The MRI study should cover the whole brain including different weighted sequences in three planes. Interpretation should be performed by experienced readers and particularly focused on the brain area suspected as the epileptogenic zone (EZ). In non-lesional MRI patients, re-evaluation of MRI could be helpful after all ancillary tests are completed, including nuclear medicine and invasive electrophysiological investigation, such as stereo-electroencephalography (SEEG), to search retrospectively for subtle structural lesions.

Keywords

Neocortical epilepsy Malformation of cortical development Focal cortical dysplasia Post-stroke epilepsy Post-traumatic epilepsy 

List of Abbreviations

18F-FDG PET

18-Fluoro-2-deoxyglucose positron emission tomography

DRFE

Drug-resistant focal epilepsy

EZ

Epileptogenic zone

FCD

Focal cortical dysplasia

HME

Hemimegalencephaly

HTP

Heterotopia

MCDs

Malformations of cortical development

PMG

Polymicrogyria

PSE

Post-stroke epilepsy

PSS

Post-stroke seizures

PTE

Post-traumatic epilepsy

PTS

Post-traumatic seizures

SISCOM

Subtracted ictal SPECT co-registered to MRI

References

  1. Barkovich AJ, Guerrini R, Kuzniecky RI, et al. A developmental and genetic classifications for malformations of cortical development: update 2012. Brain. 2012;135:1348–69.  https://doi.org/10.1093/brain/aws019.CrossRefPubMedPubMedCentralGoogle Scholar
  2. Benbir G, Ince B, Bozluolcay M. The epidemiology of post-stroke epilepsy according to stroke subtypes. Acta Neurol Scand. 2006;114(1):8–12.  https://doi.org/10.1111/j.1600-0404.2006.00642.x.CrossRefPubMedGoogle Scholar
  3. Blümcke I, Thom M, Aronica E, et al. The clinicopathologic spectrum of focal cortical dysplasias: a consensus classification proposed by an ad hoc task force of the ILAE diagnostic methods commission. Epilepsia. 2011;52(1):158–74.  https://doi.org/10.1111/j.1528-1167.2010.02777.x.CrossRefPubMedGoogle Scholar
  4. Blümcke I, Spreafico R, Haaker G, et al. Histopathologic findings in brain tissue obtained during epilepsy surgery. N Engl J Med. 2017;377:1648–56.  https://doi.org/10.1056/NEJMoa1703784.CrossRefPubMedGoogle Scholar
  5. Colombo N, Tassi L, Deleo F, et al. Focal cortical dysplasia type IIa and type IIb: MRI aspects in 118 cases proven by histopathology. Neuroradiology. 2012;54(10):1065–77.  https://doi.org/10.1007/s00234-012-1049-1.CrossRefPubMedGoogle Scholar
  6. Holthausen H, Pieper T, Coras R, et al. Isolated focal cortical dysplasias type Ia (FCD type Ia) as cause of severe focal epilepsies in children. Neuropediatrics. 2014;45(Suppl):51–5.  https://doi.org/10.1055/s-0034-1390564.CrossRefGoogle Scholar
  7. Pitkänen A, Immonen R. Epilepsy related to traumatic brain injury. Neurotherapeutics. 2014;11(2):286–96.  https://doi.org/10.1007/s13311-014-0260-7.CrossRefPubMedPubMedCentralGoogle Scholar
  8. Rossini L, Villani F, Granata T, et al. FCD type II and mTOR pathway: evidence for different mechanisms involved in the pathogenesis of dysmorphic neurons. Epilepsy Res. 2017;129:146–56.  https://doi.org/10.1016/j.eplepsyres.2016.12.002.CrossRefPubMedGoogle Scholar
  9. Tassi L, Garbelli R, Colombo N, et al. Type I focal cortical dysplasia: surgical outcome is related to histopathology. Epileptic Disord. 2010;12:181–91.  https://doi.org/10.1684/epd.2010.0327.CrossRefPubMedGoogle Scholar
  10. Tassi L, Garbelli R, Colombo N, et al. Electroclinical, MRI and surgical outcomes in 100 epileptic patients with type II FCD. Epileptic Disord. 2012;14(3):257–66.  https://doi.org/10.1684/epd.2012.0525.CrossRefPubMedGoogle Scholar
  11. Taylor DC, Falconer MA, Bruton CJ, et al. Focal dysplasia of the cerebral cortex in epilepsy. J Neurol Neurosurg Psychiatry. 1971;34:369–87.Google Scholar

Suggested Readings

  1. Barkovich AJ, Dobyns WB, Guerrini R. Malformations of cortical development and epilepsy. Cold Spring Harb Perspect Med. 2015;5(5):a022392.  https://doi.org/10.1101/cshperspect.a022392.CrossRefPubMedPubMedCentralGoogle Scholar
  2. Bernasconi A, Bernasconi N, Bernhardt BC, et al. Advances in MRI for “cryptogenic” epilepsies. Nat Rev Neurol. 2011;7:99–108.  https://doi.org/10.1038/nrneurol.2010.199.CrossRefPubMedGoogle Scholar
  3. Cianfoni A, Caulo M, Cerase A, et al. Seizure-induced brain lesions: a wide spectrum of variably reversible MRI abnormalities. Eur J Radiol. 2013;82(11):1964–72.  https://doi.org/10.1016/j.ejrad.2013.05.020.CrossRefPubMedGoogle Scholar
  4. Cossu M, Pelliccia V, Gozzo F, et al. Surgical treatment of polymicrogyria-related epilepsy. Epilepsia. 2016;57(12):2001–10.  https://doi.org/10.1111/epi.13589.CrossRefPubMedGoogle Scholar
  5. Mellerio C, Labeyrie MA, Chassoux F, et al. 3T MRI improves the detection of transmantle sign in type 2 focal cortical dysplasia. Epilepsia. 2014;55(1):117–22.  https://doi.org/10.1111/epi.12464.CrossRefPubMedGoogle Scholar
  6. Pitkänen A, Roivainen R, Lukasiuk K. Development of epilepsy after ischaemic stroke. Lancet Neurol. 2016;15(2):185–97.CrossRefPubMedGoogle Scholar
  7. Thesen T, Quinn BT, Carlson C, et al. Detection of epileptogenic cortical malformations with surface-based MRI morphometry. PLoS One. 2011;6(2):e16430.  https://doi.org/10.1371/journal.pone.0016430.CrossRefPubMedPubMedCentralGoogle Scholar
  8. Wagner J, Weber B, Urbach H, et al. Morphometric MRI analysis improves detection of focal cortical dysplasia type II. Brain. 2011;134(Pt 10):2844–54.  https://doi.org/10.1093/brain/awr204.CrossRefPubMedGoogle Scholar
  9. Veersema TJ, Ferrier CH, Van Eijsden P, et al. Seven tesla MRI improves detection of focal cortical dysplasia in patients with refractory focal epilepsy. Epilepsia Open. 2017;2(2):162–71.  https://doi.org/10.1002/epi4.12041.CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Neuroradiology Department, Centro Regionale Chirurgia dell’Epilessia “Claudio Munari”ASST Grande Ospedale Metropolitano Niguarda Cà GrandaMilanoItaly
  2. 2.Magnetic Resonance Image Core Facility. Institut de Investigació Biomèdica August Pi I Sunyer (IDIBAPS)Image Diagnosis Center (CDIC). Hospital Clínic de BarcelonaBarcelonaSpain
  3. 3.Neuroimaging Laboratory Scientific Institute IRCCS Eugenio MedeaLeccoItaly

Section editors and affiliations

  • Nuria Bargalló
    • 1
    • 2
  1. 1.Image Diagnosis Center (CDIC)Hospital Clínic de BarcelonaBarcelonaSpain
  2. 2.Magnetic Resonance Image Core FacilityInstitut de Investigació Biomèdica August Pi I Sunyer (IDIBAPS)BarcelonaSpain

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