Diffusion tensor imaging in euthymic bipolar disorder - A tract-based spatial statistics study.

Area of Science:

• Neuroimaging
• Neuroscience
• Psychiatry

Background:

• Bipolar I disorder (BD-I) is a mood disorder characterized by manic episodes.
• Euthymic phase in BD-I is crucial for understanding underlying neurobiology.
• Diffusion Tensor Imaging (DTI) is a neuroimaging technique used to study white matter integrity.

Purpose of the Study:

• To compare white matter microstructure in euthymic BD-I patients and healthy controls (HC).
• To investigate the effects of lithium treatment on white matter integrity in BD-I patients.
• To explore correlations between white matter measures and clinical variables in BD-I.

Main Methods:

• Used DTI to acquire diffusion-weighted and T1-weighted MRI scans from 21 euthymic BD-I patients and 22 HC.
• Estimated fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD).
• Employed FSL Tract Based Spatial Statistics (TBSS) for group comparisons and correlation analyses.

Main Results:

• No significant differences in FA, MD, RD, or AD were detected between euthymic BD-I patients and HC.
• Lithium-using BD-I patients showed higher FA and lower RD in the corpus callosum and left anterior corona radiata compared to non-lithium-users.
• Negative FA and positive RD/MD associations were observed with minor depressive symptoms.

Conclusions:

• Microstructural differences in euthymic BD-I patients may be less pronounced than previously reported.
• Lithium treatment may exert a counteracting effect on white matter microstructural disturbances in BD-I.
• Further research with larger sample sizes is warranted to confirm these findings.