title: Microstructural Differences in the Corpus Callosum in Patients With Bipolar Disorder and Major Depressive Disorder.
abstract: It is difficult to distinguish between bipolar disorder and major depressive disorder (MDD) in patients lacking a clear history of mania. There is an urgent need for an objective biomarker for differential diagnosis. Using diffusion tensor imaging, this study investigated the differences in the brain white matter microstructure between patients with bipolar disorder and MDD.
  
  
  
  Participants included 16 patients with bipolar disorder and 23 patients with MDD having depressed or euthymic states based on DSM-IV-TR criteria and 23 healthy volunteers. Whole-brain voxel-based morphometric analysis was used to detect any significant differences in fractional anisotropy between patients with bipolar disorder and MDD. The study was conducted between August 2011 and July 2015.
  
  
  
  We found a significant decrease in fractional anisotropy values in the anterior part of the corpus callosum in patients with bipolar disorder compared with MDD (P < .001), which did not depend on the patients' affective state. This decrease was associated with increased radial diffusivity values (P < .05), which was also found in patients with bipolar disorder when compared with healthy volunteers (P < .05). We predicted bipolar disorder and MDD in all patients using the fractional anisotropy values, with a correct classification rate of 76.9%.
  
  
  
  The present study revealed that patients with bipolar disorder have microstructural abnormalities in the corpus callosum during depressed or euthymic states, which may deteriorate the exchange of emotional information between the cerebral hemispheres, resulting in emotional dysregulation. Our results indicate the possible use of diffusion tensor imaging as a differential diagnostic tool.
authors: Department of Psychiatry, Nara Medical University, Kashihara, Japan.
authors: Kiwamu
authors: K
authors: Matsuoka
authors: Department of Psychiatry, Nara Medical University, 840 Shijocho, Kashihara, Nara, 634-8522, Japan. ejm86rp@yahoo.co.jp.|Department of Psychiatry, Nara Medical University, Kashihara, Japan.|Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Suita, Japan.
authors: Fumihiko
authors: F
authors: Yasuno
authors: Department of Psychiatry, Nara Medical University, Kashihara, Japan.
authors: Toshifumi
authors: T
authors: Kishimoto
authors: Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Suita, Japan.
authors: Akihide
authors: A
authors: Yamamoto
authors: Department of Psychiatry, Nara Medical University, Kashihara, Japan.
authors: Kuniaki
authors: K
authors: Kiuchi
authors: Department of Psychiatry, Nara Medical University, Kashihara, Japan.
authors: Jun
authors: J
authors: Kosaka
authors: Department of Neurology, National Cerebral and Cardiovascular Center, Suita, Japan.
authors: Kazuyuki
authors: K
authors: Nagatsuka
authors: Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Suita, Japan.
authors: Hidehiro
authors: H
authors: Iida
authors: Department of Psychiatry, Osaka University Health Care Center, Suita, Japan.
authors: Takashi
authors: T
authors: Kudo
mesh_terms: D000328:Adult; D016880:Anisotropy; D001714:Bipolar Disorder / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D003337:Corpus Callosum / Q000473:pathology*; D003865:Major Depressive Disorder / Q000473:pathology*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D066127:White Matter / Q000473:pathology