title: High angular resolution diffusion imaging in a child with autism spectrum disorder and comparison with his unaffected identical twin.
abstract: In recent years, the use of brain diffusion MRI has led to the hypothesis that children with autism spectrum disorder (ASD) show abnormally connected brains. We used the model of disease-discordant identical twins to test the hypothesis that higher-order diffusion MRI protocols are able to detect abnormal connectivity in a single subject. We studied the structural connectivity of the brain of a child with ASD, and of that of his unaffected identical twin, using high angular resolution diffusion imaging (HARDI) probabilistic tractography. Cortical regions were automatically parcellated from high-resolution structural images, and HARDI-based connection matrices were produced for statistical comparison. Differences in diffusion indexes between subjects were tested by Wilcoxon signed rank test. Tracts were defined as discordant when they showed a between-subject difference of 10 percent or more. Around 11 percent of the discordant intra-hemispheric tracts showed lower fractional anisotropy (FA) values in the ASD twin, while only 1 percent showed higher values. This difference was significant. Our findings in a disease-discordant identical twin pair confirm previous literature consistently reporting lower FA values in children with ASD.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Conti
authors.forename: Kerstin
authors.initials: K
authors.lastname: Pannek
authors.forename: Sara
authors.initials: S
authors.lastname: Calderoni
authors.forename: Anna
authors.initials: A
authors.lastname: Gaglianese
authors.forename: Simona
authors.initials: S
authors.lastname: Fiori
authors.forename: Paola
authors.initials: P
authors.lastname: Brovedani
authors.forename: Danilo
authors.initials: D
authors.lastname: Scelfo
authors.forename: Stephen
authors.initials: S
authors.lastname: Rose
authors.forename: Michela
authors.initials: M
authors.lastname: Tosetti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cioni
authors.forename: Andrea
authors.initials: A
authors.lastname: Guzzetta
mesh_terms: D016880:Anisotropy; D000067877:Autism Spectrum Disorder / Q000473:pathology*; D001921:Brain / Q000033:anatomy & histology / Q000473:pathology*; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D006801:Humans; D008297:Male; D014430:Twins, Monozygotic