Detecting response of rat C6 glioma tumors to radiotherapy using hyperpolarized 1-13Cpyruvate and 13C magnetic resonance spectroscopic imaging

摘要

¹³C chemical shift images acquired following intravenous injection of hyperpolarized [1-¹³C]pyruvate into rats with implanted C6 gliomas showed significant labeling of lactate within the tumors but not in surrounding brain tissue. Signal from pyruvate was observed in blood vessels above the brain and from other major vessels elsewhere in the rat head. Pyruvate was largely undetectable within the tumor or surrounding normal brain tissue. The ratio of hyperpolarized ¹³C label in the injected pyruvate and endogenous lactate was decreased from 0.25 +/− 0.13 to 0.13 +/− 0.08, (a reduction of 48%) at 96 h following whole brain irradiation with 15 Gy. These data suggest that hyperpolarized [1-¹³C]pyruvate may be useful in detecting treatment response in gliomas, where the use of ¹⁸FDG-PET is limited by the high background signals from normal brain tissue.