Hyperpolarized 13C MRSI detects immunomodulatory responses to dimethyl fumarate and fingolimod therapies in a model of multiple sclerosis

We used hyperpolarized 13C MR spectroscopy imaging (MRSI) in a multiple sclerosis model and showed that we could monitor immune cell activation by measuring hyperpolarized [1-13C]pyruvate conversion to lactate. We further demonstrated that this approach detected response to two existing treatments, fingolimod and dimethyl fumarate. We observed a reduction of pyruvate-to-lactate flux after treatment, that can be explained by increased pyruvate dehydrogenase activity and decrease of immune cells. In addition, we evaluated brain perfusion using hyperpolarized [13C]urea, but saw no therapy effect. Altogether, we demonstrated that hyperpolarized 13C MRSI has potential to monitor immunomodulatory therapies within the central nervous system.