title: Increased fractional anisotropy in cerebellum in obsessive-compulsive disorder.
abstract: BACKGROUND
  Previous morphology and diffusion-imaging studies have suggested that structural changes in white matter is an important part of the pathophysiology of obsessive-compulsive disorder (OCD). However, different methodological approaches and the heterogeneity of patient samples question the validity of the findings. Materials and methods In total, 30 patients were matched for age and sex with 30 healthy controls. All participants underwent T1-weighted magnetic resonance imaging, diffusion tensor imaging and T2 fluid-attenuated inversion recovery. Voxel-based morphometry and tract-based spatial statistics were used to compare white matter volumes and diffusion tensor imaging between groups. These data were analysed correcting for the effects of multiple comparisons, age, sex, severity and duration of illness as nuisance covariates. White matter hyperintensities were manually identified.
  
  
  RESULTS
  Increase in fractional anisotropy in cerebellum was the most prominent result. A decrease in fractional anisotrophy in patients comparable with previous studies was located in forceps minor. There were no differences in the white matter morphology or in the white matter hyperintensities between patients and healthy controls.
  
  
  CONCLUSIONS
  Decrease in fractional anisotrophy in forceps minor and increase in cerebellum were found, and they were not due to neither white matter hyperintensities nor morphology of the white matter. Cerebellar hyperconnectivity could be an important part of OCD pathophysiology.
authors.affiliation: 1Department of Clinical Medicine,Aarhus University,Translational Neuropsychiatry Unit,Risskov,Denmark.
authors.forename: Tue
authors.initials: T
authors.lastname: Hartmann
authors.affiliation: 2Clinic for OCD and Anxiety Disorders,Aarhus University Hospital Risskov,Risskov,Denmark.
authors.forename: Sanne
authors.initials: S
authors.lastname: Vandborg
authors.affiliation: 1Department of Clinical Medicine,Aarhus University,Translational Neuropsychiatry Unit,Risskov,Denmark.
authors.forename: Raben
authors.initials: R
authors.lastname: Rosenberg
authors.affiliation: 3Department of Clinical Medicine and Diagnostic Radiology,Aarhus University,Risskov,Denmark.
authors.forename: Leif
authors.initials: L
authors.lastname: Sørensen
authors.affiliation: 4Department of Affective Disorders,Aarhus University Hospital Risskov,Risskov,Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Videbech
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000000981:diagnostic imaging / Q000473:pathology*; D011569:Psychiatric Status Rating Scales; D066127:White Matter / Q000000981:diagnostic imaging / Q000473:pathology*; D055815:Young Adult
keywords: neuroimaging; obsessive–compulsive disorder; pathophysiology; prefrontal cortex