The authors of this paper do not have any commercial associations that might pose a conflict of interest in connection with this manuscript.
White matter abnormalities in bipolar disorder: a voxel-based diffusion tensor imaging study
Version of Record online: 30 APR 2008
Copyright © Blackwell Munksgaard 2008
Volume 10, Issue 4, pages 460–468, June 2008
How to Cite
Bruno, S., Cercignani, M. and Ron, M. A. (2008), White matter abnormalities in bipolar disorder: a voxel-based diffusion tensor imaging study. Bipolar Disorders, 10: 460–468. doi: 10.1111/j.1399-5618.2007.00552.x
- Issue online: 30 APR 2008
- Version of Record online: 30 APR 2008
- Received 2 March 2007, revised and accepted for publication 14 September 2007
Vol. 10, Issue 5, 657, Version of Record online: 4 JUL 2008
- bipolar disorder;
- diffusion tensor imaging;
- fractional anisotropy;
- mean diffusivity
Objectives: In bipolar disorder (BD), dysregulation of mood may result from white matter abnormalities that disrupt fronto-subcortical circuits. In this study, we explore such abnormalities using diffusion tensor imaging (DTI), an imaging technique capable of detecting subtle changes not visible with conventional magnetic resonance imaging (MRI), and voxel-based analysis.
Methods: Thirty-six patients with BD, all but two receiving antidepressants or mood stabilizers, and 28 healthy controls matched for age and gender were studied. Diffusion-weighted echoplanar images (DW-EPI) were obtained using a 1.5T scanner. Voxel-based analysis was performed using SPM 2. Differences between the groups in mean diffusivity and fractional anisotropy (FA) were explored.
Results: In the patient group, mean diffusivity was increased in the right posterior frontal and bilateral prefrontal white matter, while FA was increased in the inferior, middle temporal and middle occipital regions. The areas of increased mean diffusivity overlapped with those previously found to be abnormal using volumetric MRI and magnetization transfer imaging (MTI) in the same group of patients.
Conclusions: White matter abnormalities, predominantly in the fronto-temporal regions, can be detected in patients with BD using DTI. The neuropathology of these abnormalities is uncertain, but neuronal and axonal loss, myelin abnormalities and alterations in axonal packing density are likely to be relevant. The neuroprotective effects of some antidepressants and mood stabilizers make it unlikely that medication effects could explain the abnormalities described here, although minor effects cannot be excluded.