Hyperpolarized (13)C MRI of Tumor Metabolism Demonstrates Early Metabolic Response to Neoadjuvant Chemotherapy in Breast Cancer

PURPOSE: To compare hyperpolarized carbon 13 ((13)C) MRI with dynamic contrast material–enhanced (DCE) MRI in the detection of early treatment response in breast cancer. MATERIALS AND METHODS: In this institutional review board–approved prospective study, a woman with triple-negative breast cancer (age, 49 years) underwent (13)C MRI after injection of hyperpolarized [1–carbon 13 {(13)C}]-pyruvate and DCE MRI at 3 T at baseline and after one cycle of neoadjuvant therapy. The (13)C-labeled lactate-to-pyruvate ratio derived from hyperpolarized (13)C MRI and the pharmacokinetic parameters transfer constant (K(trans)) and washout parameter (k(ep)) derived from DCE MRI were compared before and after treatment. RESULTS: Exchange of the (13)C label between injected hyperpolarized [1-(13)C]-pyruvate and the endogenous lactate pool was observed, catalyzed by the enzyme lactate dehydrogenase. After one cycle of neoadjuvant chemotherapy, a 34% reduction in the (13)C-labeled lactate-to-pyruvate ratio resulted in correct identification of the patient as a responder to therapy, which was subsequently confirmed via a complete pathologic response. However, DCE MRI showed an increase in mean K(trans) (132%) and mean k(ep) (31%), which could be incorrectly interpreted as a poor response to treatment. CONCLUSION: Hyperpolarized (13)C MRI enabled successful identification of breast cancer response after one cycle of neoadjuvant chemotherapy and may improve response prediction when used in conjunction with multiparametric proton MRI. Keywords: Breast, MR-Spectroscopy, Molecular Imaging-Cancer, Molecular Imaging-Clinical Translation, Neoplasms-Primary, Oncology, Tumor Response Published under a CC BY 4.0 license.