Development of methods and feasibility of using hyperpolarized carbon-13 imaging data for evaluating brain metabolism in patient studies.

PURPOSE

Hyperpolarized C metabolic imaging is a non-invasive imaging modality for evaluating real-time metabolism. The purpose of this study was to develop and implement experimental strategies for using [1-C]pyruvate to probe metabolism for patients with brain tumors and other neurological diseases.

METHODS

The C RF coils and pulse sequences were tested in a phantom and were performed using a 3T whole body scanner. Samples of [1-C]pyruvate were polarized using a SPINlab system. Dynamic C data were acquired from eight patients previously diagnosed with brain tumors, who had received treatment and were being followed with serial MR scans.

RESULTS

The phantom studies produced good quality spectra with a reduction in signal intensity in the center due to the reception profiles of the C receive coils. Dynamic data obtained from a 3 cm slice through a patient’s brain following injection with [1-C]pyruvate showed the anticipated arrival of the agent, its conversion to lactate and bicarbonate, and subsequent reduction in signal intensity. A similar temporal pattern was observed in 2D dynamic patient studies, with signals corresponding to pyruvate, lactate and bicarbonate being in normal appearing brain but only pyruvate and lactate being detected in regions corresponding to the anatomic lesion. Physiological monitoring and follow-up confirmed that there were no adverse events associated with the injection.

CONCLUSIONS

This study has presented the first application of hyperpolarized C metabolic imaging in patients with brain tumor and demonstrated the safety and feasibility of using hyperpolarized [1-C]pyruvate to evaluate in vivo brain metabolism.