Current and Potential Applications of Clinical 13C MR Spectroscopy

Abstract

In this article, the current and potential clinical roles of ¹³C magnetic resonance spectroscopy (MRS) and ¹³C magnetic resonance spectroscopic imaging are presented, with a focus on applications to prostate cancer and hyperpolarized ¹³C spectroscopic imaging. The advantages of ¹³C MRS have been its chemical specificity and lack of background signal, with the major disadvantage being its inherently low sensitivity and the subsequent inability to acquire data at a high-enough spatial and temporal resolution to be routinely applicable in the clinic. The approaches to improving the sensitivity of ¹³C spectroscopy have been to perform proton decoupling and to use endogenous ¹³C-labeled or enhanced metabolic substrates. With these nominal increases in signal-to-noise ratio, ¹³C MRS using labeled metabolic substrates has shown diagnostic promise in patients and has been approved by the Food and Drug Administration. The development of technology that applies dynamic nuclear polarization to generate hyperpolarized ¹³C-labeled metabolic substrates, and the development of a process for delivering them into living subjects, have totally changed the clinical potential of MRS of ¹³C-labeled metabolic substrates. Preliminary preclinical studies in a model of prostate cancer have demonstrated the potential clinical utility of hyperpolarized ¹³C MRS.