We used hyperpolarized 13C magnetic resonance spectroscopic imaging (HP 13C MRSI) and T1-MRI to assess dimethyl fumarate (DMF) response in a model of multiple sclerosis (MS). Gadolinium-enhanced T1-MRI showed blood-brain-barrier breakdown, regardless of DMF treatment. In contrast, DMF therapy prevented an increase compared to untreated MS animals in HP 13C lactate, HP 13C lactate-to-pyruvate and HP 13C lactate-to-(pyruvate/urea) ratios. HP 13C MRSI findings were further correlated to pyruvate dehydrogenase activity and pro-inflammatory macrophages. Altogether, we demonstrated that HP 13C MRSI has potential to monitor the effect of immunomodulatory therapies within the central nervous system.