title: Type II focal cortical dysplasia: Ex vivo 7T magnetic resonance imaging abnormalities and histopathological comparisons.
abstract: OBJECTIVE
  In the present report, the correlations between ex vivo high-resolution imaging and specific histological and ultrastructural patterns in type II focal cortical dysplasia (FCD) have been studied to explain the differences in the magnetic resonance imaging (MRI) detection of dysplasia and to contribute to the presurgical imaging evaluation of this pathology.
  
  
  METHODS
  Surgical specimens from 13 patients with FCD IIa/b were submitted to 7T MRI scanning, and then analyzed histologically and ultrastructurally to compare the results with the MRI findings. Region of interest (ROI)-based measures on T2-weighted images (T2wi) were quantitatively evaluated in the lesion and in adjacent perilesional gray and white matter.
  
  
  RESULTS
  Matched histological sections and 7T T2wi showed that the core of the lesion was characterized by patchy aggregates of abnormal cells and fiber disorganization related to inhomogeneity of intracortical signal intensity. The quantitative approach on T2wi can help to distinguish the lesions and perilesional areas even in a clinical MRI-negative case. The ultrastructural study showed that the strong signal hyperintensity in the white matter of FCD IIb was related to a dysmyelination process associated with severe fiber loss and abnormal cells. Less severe histopathological features were found in FCD IIa, thus reflecting their less evident MRI alterations.
  
  
  CONCLUSIONS
  We suggest that white matter abnormalities in type IIb FCD are due to defects of the myelination processes and maturation, impaired by the presence of balloon cells. To reveal the presence and the border of type II cortical dysplasia on MRI, a quantitative ROI-based analysis (coefficient of variation) is also proposed.
authors.affiliation: Scientific Department, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: Ileana
authors.initials: I
authors.lastname: Zucca
authors.affiliation: Clinical Epileptology and Experimental Neurophysiology Unit, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Gloria
authors.initials: G
authors.lastname: Milesi
authors.affiliation: Clinical Epileptology and Experimental Neurophysiology Unit, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Medici
authors.affiliation: C. Munari Epilepsy Surgery Center, Niguarda Hospital, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Tassi
authors.affiliation: Clinical Epileptology and Experimental Neurophysiology Unit, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Didato
authors.affiliation: C. Munari Epilepsy Surgery Center, Niguarda Hospital, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Cardinale
authors.affiliation: Neurosurgery Unit, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tringali
authors.affiliation: Department of Neuroradiology, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Colombo
authors.affiliation: Department of Pathology, Niguarda Hospital, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Bramerio
authors.affiliation: Neuroradiology Unit, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: Ludovico
authors.initials: L
authors.lastname: D'Incerti
authors.affiliation: Department of Pediatric Neuroscience, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Freri
authors.affiliation: Neurology V and Neuropathology, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Morbin
authors.affiliation: Neurology V and Neuropathology, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Fugnanesi
authors.affiliation: Scientific Department, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Figini
authors.affiliation: Clinical Epileptology and Experimental Neurophysiology Unit, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Spreafico
authors.affiliation: Clinical Epileptology and Experimental Neurophysiology Unit, C. Besta Neurological Institute Foundation, Milan, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Garbelli
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D065703:Malformations of Cortical Development, Group I / Q000473:pathology*; D008875:Middle Aged; D066127:White Matter / Q000473:pathology* / Q000648:ultrastructure; D055815:Young Adult