Hyperpolarized 13C MRI was used to acquire images of [1-13C]lactate and 13C-bicarbonate from the injected [1-13C]pyruvate in 8 patients with brain metastases. Lesions were manually contoured and the mean tumor 13C-lactate signal was converted to a z-score by extending the approach previously described in Lee et al. (2019). As expected, the z-score ranks of the anatomical regions were less concordant in patients compared to controls. A range of lactate z-scores were observed in metastatic lesions, showing metabolic heterogeneity consistent with the known heterogeneity in metastatic features and clinical status. The lesions with the highest and 5th highest lactate z-scores progressed.