a) Profile tumors in terms of tumor vascular permeability and oxygenation using in vivo hyperpolarization of water at low fields. Hyperpolarization is usually carried out with the paramagnetic molecule TAM. From the image intensity profiles we obtained tumor oxygen and tumor vascular permeability simultaneously and correlated with immunohistochemical characterization of tumors. We found that tumor hypoxia was associated with increased tumor vascular permeability which in turn was negatively correlated with vascular pericyte coverage. b) Monitor the in vivo breakdown patterns of hyperpolarized (ex vivo) 13C-labeled pyruvic acid in tumors as indicators of treatment response: In this study, we injected 13C labeled pyruvate and monitored the conversion to lactate. The ratiometric images lactate/pyruvate can provide information on response to treatment if the ratios decrease. We used this imaging modality to evaluate treatment response in SCC VII tumors in mice treated with rapamycin and sunitinib. Preliminary results show that 13C imaging monitoring the breakdown of lactate/pyruvate was predictive in treatment response.
