Similarities and differences of white matter connectivity and water diffusivity in bipolar I and II disorder.

Differences and similarities in microstructural white matter alterations between bipolar I and bipolar II disorder were investigated. Twelve patients with bipolar I disorder, 12 patients with bipolar II disorder and 22 healthy controls underwent diffusion tensor imaging. Fractional anisotropy (FA) and mean apparent diffusion coefficient (ADC) maps were compared between groups using voxel-based whole brain analyses. Both bipolar I and II groups had a FA decrease in the corpus callosum, cingulate and right prefrontal regions, and a ADC increase in the medial frontal, anterior cingulate, insular and temporal regions, compared to controls. The bipolar I group had a FA decrease in the right temporal white matter and a ADC increase in the frontal, temporal, parietal and thalamic regions, compared to the bipolar II group. The results suggest disrupted integrity of commissural fibers and white matter in the anterior paralimbic structures in bipolar disorder. Relative sparing of the dorsal system and long association fibers may differentiate bipolar II from I disorder.

Ha TH ，Her JY ，Kim JH ，Chang JS ，Cho HS ，Ha K ... -  《-》

Microstructural white matter changes in euthymic bipolar patients: a whole-brain diffusion tensor imaging study.

Wessa M ，Houenou J ，Leboyer M ，Chanraud S ，Poupon C ，Martinot JL ，Paillère-Martinot ML ... -  《-》

White matter connectivity in bipolar disorder.

Brambilla P ，Bellani M ，Yeh PH ，Soares JC ，Tansella M ... -  《-》

Limbic and callosal white matter changes in euthymic bipolar I disorder: an advanced diffusion magnetic resonance imaging tractography study.

White matter microstructural changes detected using diffusion tensor imaging have been reported in bipolar disorder. However, findings are heterogeneous, which may be related to the use of analysis techniques that cannot adequately model crossing fibers in the brain. We therefore sought to identify altered diffusion anisotropy and diffusivity changes using an improved high angular resolution fiber-tracking technique. Diffusion magnetic resonance imaging data was obtained from 35 prospectively confirmed euthymic bipolar disorder type 1 patients (age 22-59) and 43 control subjects (age 22-59) drawn from a sample of 120 age- and gender-matched demographically similar case-control pairs. Tractography using a constrained spherical deconvolution approach to account for crossing fibers was implemented. Changes in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity between patient and control groups in subdivisions of the corpus callosum, cingulum, and fornix were measured as indicators of trait differences in white matter microstructural organization in bipolar disorder. Patients had significantly reduced fractional anisotropy and increased mean diffusivity and radial diffusivity in all divisions of the corpus callosum, left fornix, and subgenual cingulum compared with control subjects. Axial diffusivity was increased in the fornix bilaterally and right dorsal-anterior cingulum. By using an improved fiber-tracking method in a clinically homogeneous population, we were able to localize trait diffusivity changes to specific subdivisions of limbic fiber pathways, including the fornix. Our findings extend previous reports of altered limbic system microstructural disorganization as a trait feature of bipolar disorder.

Emsell L ，Leemans A ，Langan C ，Van Hecke W ，Barker GJ ，McCarthy P ，Jeurissen B ，Sijbers J ，Sunaert S ，Cannon DM ，McDonald C ... -  《-》

Limbic and corpus callosum aberrations in adolescents with bipolar disorder: a tract-based spatial statistics analysis.

Barnea-Goraly N ，Chang KD ，Karchemskiy A ，Howe ME ，Reiss AL ... -  《-》