The effect of elevated serum lactate on measures of apparent cerebral metabolism and perfusion in the anesthetised rodent brain.

It is unclear how serum lactate perturbations influence the quantification of cerebral blood flow (CBF) and metabolism using proton perfusion imaging and hyperpolarized 13C MRI. Low dosage L-lactate injection increased CBF and cerebral LDH flux, whilst high dosage lactate decreased CBF and maintained the increased LDH flux, relative to saline administration. Lactate administration did not alter apparent oxidative metabolism. This suggests the efficacy of probing oxidative metabolism with 13C MRI when alterations in serum lactate are present (e.g. in pathology). But highlights the requirement for serum lactate measurement prior to interpretation of 13C metabolic data.