Hyperpolarized Pyruvate (13C) MR Imaging in Monitoring Patients With Prostate Cancer on Active Surveillance

PRIMARY OBJECTIVES: I. Optimize the imaging sequences that maximize signal-to-noise ratio (SNR) and intra-tumoral conversion of HP 13C pyruvate to lactate (kPL) and HP 13C pyruvate to glutamate (kPG) in regions of tumor versus (vs.) adjacent benign tissue as assessed by multi-parametric MRI (mpMRI) imaging characteristics. (Part 1) II. Determine the association between intra-tumoral kPL and kPG with Gleason grade determined during magnetic resonance (MR)/ultrasound (US)-guided fusion prostate biopsies obtained within 6 months following baseline HP C-13 pyruvate MR exam. (Part 2) SECONDARY OBJECTIVES: I. Evaluate the intra-patient variability in intra-tumoral kPL and kPG with repeated dose studies. II. Determine the association between peak intra-tumoral kPL observed on baseline imaging with serum prostate specific antigen (PSA). III. Compare and contrast intra-tumoral kPL and kPG with prostate imaging reporting and data system (PI-RADS) version 2 and individual mpMRI parameters including apparent diffusion coefficient (ADC) on diffusion-weighted imaging. IV. Describe the frequency of up-grading of tumor with MR/US-guided fusion biopsy obtained following baseline HP C-13 MR exam. V. Further characterize the safety profile of HP C-13 pyruvate injections. EXPLORATORY OBJECTIVES: I. Correlate peak intra-tumoral kPL with results of gene expression profiling using DECIPHER assay. II. Correlate peak intra-tumoral kPL and kPG with DECIPHER GRID tumor ribonucleic acid (RNA) expression of relevant components of the glycolytic pathway including lactate dehydrogenase (LDH), pyruvate dehydrogenase (PDH), aconitate hydratase (aconitase), myelocytomatosis oncogene (MYC), monocarboxylate transporter 4 (MCT4) (lactate transporter). III. For patients who undergo optional follow-up HP C-13 pyruvate/MRI 6-15 months following baseline scan, determine the mean percent change from baseline in intra-tumoral kPL and kPG and whether the change from baseline is associated change in clinical risk assessment as determined by University of California, San Francisco (UCSF)-Cancer of the Prostate Risk Assessment (CAPRA) risk score. OUTLINE: Patients receive hyperpolarized carbon C 13 pyruvate intravenously (IV) over less than one minute, then undergo magnetic resonance spectroscopic imaging (MRSI) after 1-2 minutes. Within 15-60 minutes, patients may receive optional hyperpolarized carbon C 13 pyruvate and undergo MRSI. Patients also undergo MR/US fusion-guided prostate biopsy within 12 weeks following HP C-13 MRSI. After completion of study, patients will be followed up periodically.