Lithium (Li) is the first-line mood stabilizer to treat bipolar disorder patients. However, its mechanisms of action and transport across the blood-brain barrier remain poorly understood. In this study, we aimed at mapping ex vivo the cerebral Li distribution of rats treated for 28 days with Li2CO3 using 7Li-MRI at 17.2 Tesla. Using a phantom replacement approach, MRI-derived Li concentrations were calculated and validated by comparison to inductively coupled plasma-mass spectrometry (ICP-MS) measurements. Lithium distributions were uneven (normalized lithium content ranging from 0.7 to 1.4) and symmetrical with consistently lower concentrations in the metencephalon and higher ones in the cortex.