, Volume 54, Issue 10, pp 1065–1077 | Cite as

Focal cortical dysplasia type IIa and IIb: MRI aspects in 118 cases proven by histopathology

  • Nadia Colombo
  • Laura Tassi
  • Francesco Deleo
  • Alberto Citterio
  • Manuela Bramerio
  • Roberto Mai
  • Ivana Sartori
  • Francesco Cardinale
  • Giorgio Lo Russo
  • Roberto Spreafico
Continuing Education



This study aims to review the magnetic resonance imaging (MRI) aspects of a large series of patients with focal cortical dysplasia type II (FCD II) and attempt to identify distinctive features in the two histopathological subtypes IIa and IIb.


We retrospectively reviewed the MRI scans of 118 patients with histological proven FCD IIa (n = 37) or IIb (n = 81) who were surgically treated for intractable epilepsy.


MRI was abnormal in 93 patients (79 %) and unremarkable in 25 (21 %). A dysplastic lesion was identified in 90 cases (97 %) and classified as FCD II in 83 and FCD non-II in seven cases. In three cases, the MRI diagnosis was other than FCD. There was a significant association between the presence of cortical thickening (p = 0.002) and the “transmantle sign” (p < 0.001) and a correct MRI diagnosis of FCD II. MRI positivity was more frequent in the patients with FCD IIb than in those with FCD IIa (91 % vs. 51 %), and the detection rate of FCD II was also better in the patients with type IIb (88 % vs. 32 %). The transmantle sign was significantly more frequent in the IIb subgroup (p = 0.003).


The rates of abnormal MRI results and correct MRI diagnoses of FCD II were significantly higher in the IIb subgroup. Although other MRI stigmata may contribute to the diagnosis, the only significant correlation was between the transmantle sign and FCD IIb.


Epilepsy Focal cortical dysplasia type IIa and IIb MRI imaging 



We thank Dr Alessio Moscato, Medical Physics Department, Ospedale Niguarda—Milano, for his assistance in imaging editing.

Conflict of interest

We declare that we have no conflict of interest.


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Nadia Colombo
    • 1
  • Laura Tassi
    • 2
  • Francesco Deleo
    • 3
  • Alberto Citterio
    • 4
  • Manuela Bramerio
    • 5
  • Roberto Mai
    • 2
  • Ivana Sartori
    • 2
  • Francesco Cardinale
    • 2
  • Giorgio Lo Russo
    • 2
  • Roberto Spreafico
    • 3
  1. 1.Department of NeuroradiologyOspedale Cà Granda NiguardaMilanoItaly
  2. 2.Claudio Munari Epilepsy Surgery CenterOspedale NiguardaMilanoItaly
  3. 3.Department of Epilepsy Clinic and Experimental NeurophysiologyIRCCS Foundation Neurological Institute “C. Besta”MilanoItaly
  4. 4.Department of NeuroradiologyOspedale Cà Granda NiguardaMilanoItaly
  5. 5.Department of PathologyOspedale NiguardaMilanoItaly

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