Potential Clinical Roles for Metabolic Imaging with Hyperpolarized [1-13C]Pyruvate

Clinical oncology relies increasingly on biomedical imaging, with anatomical imaging, especially using CT and 1H-MRI, forming the mainstay of patient assessment, from diagnosis to treatment monitoring. However, the need for further improvements in specificity and sensitivity, coupled with imaging techniques that are reaching their limit of clinically attainable spatial resolution, has resulted in the emergence and growing use of imaging techniques with additional functional readouts, such as 18FDG-PET and multiparametric MRI. These techniques add a new dimension to our understanding of the biological behavior of tumors, allowing a more personalized approach to patient management. An important functional imaging target in cancer is metabolism. PET measurements of 18Fluorodeoxyglucose uptake (18FDG-PET), a 18F-labeled glucose analog, and 1H-MRS measurements, have both been used to investigate tumor metabolism for diagnostic purposes. However, clinical applications of MRS have been hampered by low sensitivity and consequently low spatial and temporal resolution (1). Nuclear spin hyperpolarization of 13C-labeled substrates, using dynamic nuclear polarization (DNP), which radically increases the sensitivity of these substrates to detection by 13C MRS (2), has created a renewed interest in MRS measurements of tissue metabolism. Successful translation of this technique to the clinic was achieved recently with measurements of [1-13C]pyruvate metabolism in prostate cancer (3) (see Figure 1). We explore here the potential clinical roles for metabolic imaging with hyperpolarized [1-13C]pyruvate.