White matter hemisphere asymmetries in healthy subjects and in schizophrenia: a diffusion tensor MRI study.
Hemisphere asymmetry was explored in normal healthy subjects and in patients with schizophrenia using a novel voxel-based tensor analysis applied to fractional anisotropy (FA) of the diffusion tensor. Our voxel-based approach, which requires precise spatial normalization to remove the misalignment of fiber tracts, includes generating a symmetrical group average template of the diffusion tensor by applying nonlinear elastic warping of the demons algorithm. We then normalized all 32 diffusion tensor MRIs from healthy subjects and 23 from schizophrenic subjects to the symmetrical average template. For each brain, six channels of tensor component images and one T2-weighted image were used for registration to match tensor orientation and shape between images. A statistical evaluation of white matter asymmetry was then conducted on the normalized FA images and their flipped images. In controls, we found left-higher-than-right anisotropic asymmetry in the anterior part of the corpus callosum, cingulum bundle, the optic radiation, and the superior cerebellar peduncle, and right-higher-than-left anisotropic asymmetry in the anterior limb of the internal capsule and the anterior limb's prefrontal regions, in the uncinate fasciculus, and in the superior longitudinal fasciculus. In patients, the asymmetry was lower, although still present, in the cingulum bundle and the anterior corpus callosum, and not found in the anterior limb of the internal capsule, the uncinate fasciculus, and the superior cerebellar peduncle compared to healthy subjects. These findings of anisotropic asymmetry pattern differences between healthy controls and patients with schizophrenia are likely related to neurodevelopmental abnormalities in schizophrenia.
Clinical Neuroscience Division, Laboratory of Neuroscience, Boston VA Health Care System-Brockton Division, Department of Psychiatry, Harvard Medical School, Boston, MA 02301, USA.
Hae-Jeong
HJ
Park
Carl-Fredrik
CF
Westin
Marek
M
Kubicki
Stephan E
SE
Maier
Margaret
M
Niznikiewicz
Aaron
A
Baer
Melissa
M
Frumin
Ron
R
Kikinis
Ferenc A
FA
Jolesz
Robert W
RW
McCarley
Martha E
ME
Shenton
D000328:Adult; D000465:Algorithms; D016880:Anisotropy; D016477:Artifacts; D001921:Brain / Q000473:pathology*; D002531:Cerebellum / Q000473:pathology; D003337:Corpus Callosum / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D004292:Dominance, Cerebral / Q000502:physiology*; D006179:Gyrus Cinguli / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020772:Internal Capsule / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009900:Optic Nerve / Q000473:pathology; D019580:Perforant Pathway / Q000473:pathology; D017397:Prefrontal Cortex / Q000473:pathology; D012016:Reference Values; D012559:Schizophrenia / Q000473:pathology*