title: Use of T1-weighted/T2-weighted magnetic resonance ratio images to elucidate changes in the schizophrenic brain.
abstract: BACKGROUND
  One leading hypothesis suggests that schizophrenia (SZ) is a neurodevelopmental disorder caused by genetic defects in association with environmental risk factors that affect synapse and myelin formation. Recent magnetic resonance imaging (MRI) studies of SZ brain showed both gray matter (GM) reduction and white matter (WM) fractional anisotropy reduction. In this study, we used T1-weighted (T1w)/T2-weighted (T2w) MRI ratio images, which increase myelin-related signal contrast and reduce receiver-coil bias.
  
  
  METHODS
  We measured T1w/T2w ratio image signal intensity in 29 patients with SZ and 33 healthy controls (HCs), and then compared them against bias-corrected T1w images.
  
  
  RESULTS
  Mean T1w/T2w ratio signal intensity values across all SZ GM and WM voxels were significantly lower than those for the HC values (analysis of covariance with age, gender, handedness, and premorbid intelligence quotient as nuisance covariates). SZ mean WM T1w/T2w ratio values were related to Global Assessment of Functioning (GAF) scores and were inversely related to the positive psychotic symptoms of the Positive and Negative Syndrome Scale. Voxel-based analysis revealed significantly lower T1w/T2w ratio image signal intensity values in the right ventral putamen in SZ GM. T1w image intensities did not differ between the SZ and HC groups.
  
  
  CONCLUSIONS
  T1-weighted/T2-weighted ratio imaging increased the detectability of SZ pathological changes. Reduced SZ brain signal intensity is likely due to diminished myelin content; therefore, mapping myelin-related SZ brain changes using T1w/T2w ratio images may be useful for studies of SZ brain abnormalities.
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 ; Department of System Neurophysiology Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Ishida
authors.affiliation: Department of System Neurophysiology 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: 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 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; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000473:pathology; D005260:Female; D066128:Gray Matter / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009186:Myelin Sheath / Q000473:pathology; D012559:Schizophrenia / Q000175:diagnosis / Q000473:pathology*; D066127:White Matter / Q000473:pathology
keywords: T1‐weighted/T2‐weighted ratio; magnetic resonance imaging; myelin; nucleus accumbens; schizophrenia; ventral putamen