title: DTI-based tractography of the arcuate fasciculus in patients with polymicrogyria and language disorders.
abstract: OBJECTIVE
  To assess the integrity of the arcuate fasciculus (AF) with diffusion tensor imaging (DTI) and tractography in patients with congenital polymicrogyria (PMG) and language disorders.
  
  
  METHODS
  Twelve patients with PMG and 12 matched controls were prospectively evaluated with DTI (32 gradient encoding directions, b-value=1000 s/mm(2)) at 3.0T. The AF was virtually dissected with a deterministic streamline approach. DTI metrics included FA (fractional anisotropy), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). A subset of patients (n=4) was evaluated to assess cognitive performance and language skills.
  
  
  RESULTS
  Qualitative evaluation revealed several abnormalities in tracts size and architecture in nearly all PMG patients. Remarkably, in 3 patients with bilateral PMG, the AF was not delineated on both hemispheres. In comparison to controls, patients exhibited significant decrease of FA (p=0.003) in addition to increase of RD (p=0.03) in the right AF, whereas there was significant increase of MD in the left AF (p=0.04). All 4 patients with language evaluation had suboptimal performance on lexical fluency and prosodic linguistic.
  
  
  CONCLUSIONS
  DTI and tractography suggest that the AF is severely disrupted in patients with PMG, providing an anatomical in vivo substrate for the language disorders commonly associated with these cortical malformations.
authors.affiliation: Department of Radiology and Oncology, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. Electronic address: celi.andrade@usp.br.
authors.forename: Celi S
authors.initials: CS
authors.lastname: Andrade
authors.affiliation: Department of Radiology and Oncology, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Kenya G
authors.initials: KG
authors.lastname: Figueiredo
authors.affiliation: Department of Psychiatry, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Cassia
authors.initials: C
authors.lastname: Valeriano
authors.affiliation: Department of Psychiatry, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Melanie
authors.initials: M
authors.lastname: Mendoza
authors.affiliation: Department of Psychiatry, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Kette D R
authors.initials: KD
authors.lastname: Valente
authors.affiliation: Department of Radiology and Oncology, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Maria C G
authors.initials: MC
authors.lastname: Otaduy
authors.affiliation: Department of Radiology and Oncology, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Claudia C
authors.initials: CC
authors.lastname: Leite
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007806:Language Disorders / Q000150:complications* / Q000473:pathology; D008297:Male; D065706:Polymicrogyria / Q000150:complications* / Q000473:pathology; D011446:Prospective Studies; D055815:Young Adult
keywords: Diffusion tensor imaging – fiber tractography; Language disorders; Magnetic resonance imaging; Malformations of cortical development; Polymicrogyria