Quantification of brain proton longitudinal relaxation (T ) in lithium-treated and lithium-naïve patients with bipolar disorder in comparison to healthy controls.

Background: Proton longitudinal relaxation (T ) is a quantitative MRI-derived tissue parameter sensitive to myelin, macromolecular, iron and water content. There is some evidence to suggest that cortical T is elevated in bipolar disorder and that lithium administration reduces cortical T . However, T has not yet been quantified in separate groups containing lithium-treated patients, lithium-naïve patients, and matched healthy controls.

White matter microstructural properties in bipolar disorder in relationship to the spatial distribution of lithium in the brain.

Background: Lithium treatment is associated with an increase in magnetic resonance imaging derived measures of white matter integrity, but the relationship between the spatial distribution of brain lithium and white matter integrity is unknown.

Methods: Euthymic patients with bipolar disorder receiving lithium (n = 12) and those on other medications but naïve to lithium (n = 17) underwent diffusion imaging alongside matched healthy controls (n = 16). Generalised fractional anisotropy (gFA) within white matter was compared between groups using a standard space white matter atlas.

3D Li magnetic resonance imaging of brain lithium distribution in bipolar disorder.

Lithium is a major treatment for bipolar disorder and the likelihood of a favourable response may be determined by its distribution in the brain. Lithium can be directly detected by magnetic resonance (MR), but previous Li MR spectroscopy studies have demonstrated that this is challenging compared to conventional H MR imaging due to the MR properties of the lithium nucleus and its low concentration in brain tissue, as dictated by therapeutic dose. We have tested and implemented a highly efficient balanced steady-state free precession Li-MRI method to address these challenges and enable MRI of brain lithium in a short duration scan.