title: Elucidating the aberrant brain regions in bipolar disorder using T1-weighted/T2-weighted magnetic resonance ratio images.
abstract: Although diffusion tensor imaging (DTI) have revealed brain abnormalities in bipolar disorder (BD) subjects, DTI methods might not detect disease-related abnormalities in the white matter (WM) where nerve fibers are crossing. We investigated BD myelin-related abnormal brain regions in both gray matter and WM for 29 BD and 33 healthy control (HC) participants using T1-weighted (T1w)/T2-weighted (T2w) ratio images that increase myelin-related contrast irrespective of nerve fiber orientation. To check effect of the brain volume, the results were compared with those of voxel-based morphometry (VBM). We found significantly lower T1w/T2w signal intensity in broad WM regions in BD subjects, including the corpus callosum, corona radiata, internal capsule, middle cerebellar peduncle and cerebellum. Regional volume reduction was found in the WM bilateral posterior thalami and retrolenticular part of the internal capsules of BD subjects. We also performed tract-based spatial statistics (TBSS) in 25 BD and 24 HC participants and compared those for the T1w/T2w ratio images. Both methods detected the BD corpus callosum abnormality. Further, the ratio images detected the corona radiata and the cerebellar abnormality in BD. These results suggest that T1w/T2w ratio image analysis could take a complementary role with the DTI method in elucidating myelin-related abnormalities in BD.
authors.affiliation: Department of System Neurophysiology, and Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan; Department of Neuropsychiatry, Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: ishitaku@wakayama-med.ac.jp.
authors.forename: Takuya
authors.initials: T
authors.lastname: Ishida
authors.affiliation: Department of System Neurophysiology, and Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Donishi
authors.affiliation: Department of Neuropsychiatry, Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Iwatani
authors.affiliation: Department of Neuropsychiatry, Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Neuropsychiatry, Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Neuropsychiatry, Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ukai
authors.affiliation: Department of Neuropsychiatry, Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shinosaki
authors.affiliation: Wakayama-Minami Radiology Clinic, 870-2 Kimiidera, Wakayama 641-0012, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Terada
authors.affiliation: Department of System Neurophysiology, and Graduate School of Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kaneoke
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016022:Case-Control Studies; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000503:physiopathology; D003337:Corpus Callosum / Q000000981:diagnostic imaging / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D020772:Internal Capsule / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D066127:White Matter / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: Brainstem; Diffusion tensor imaging; Fractional anisotropy; Myelin; Pontocerebellar fibers; Tract-based spatial statistics