James Slater

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

Hyperpolarized carbon‐13 (13C) metabolic imaging is a noninvasive imaging modality for evaluating real‐time metabolism. The purpose of this study was to develop and implement experimental strategies for using [1‐13C]pyruvate to probe in vivo metabolism for patients with brain tumors and other neurological diseases.

Quantification of Changes in Skeletal Muscle Amino Acid Kinetics in Adult Humans in Response to Exercise via Positron-emission Tomography with L-[methyl-11C] methionine

Dynamic positron emission tomography (PET) imaging of with L-[methyl- 11 C]methionine (11C-MET) was developed in the late 1990’s to non-invasively estimate skeletal muscle protein synthesis, but no studies have shown that the measurements respond to resistance exercise, which stimulates protein synthesis in humans. Ten healthy women aged 25-75 years underwent a 14-hour fast, followed by unilateral knee extension and flexion exercise and consumption of an 8-ounce serving of fruit juice. Five subjects underwent dynamic 11C-MET PET imaging of the mid-thigh 2-3 hours after exercise and five were imaged 1 hour after exercise. Images were processed to obtain the Patlak slope K i , which describes the fractional extraction rate of 11C-MET into skeletal muscle protein. Additionally, the images were processed with a three-compartment kinetic model to determine rate constants for 11C-MET transport between muscle tissue, protein and plasma. All subjects showed excellent mid-thigh uptake of 11C-MET. Subjects imaged 2-3 hours after exercise showed no unilateral enhancement. However, subjects imaged one hour post-exercise showed an enhancement of 11C-MET uptake in the exercised leg compared to the control leg, corresponding to K i elevations between 3.8% - 31.1%. From the three-compartment analysis, the increased uptake corresponded primarily to an increased rate constant for extraction of 11C-MET from plasma to skeletal muscle tissue. Finally, older subjects tended to have smaller values of K i than the younger subjects. In summary, 11C-MET kinetics is responsive to a unilateral exercise stimulus, and this technique may prove useful to study skeletal muscle amino acid kinetics in response to exercise, aging and other conditions

Investigation of analysis methods for hyperpolarized 13C-pyruvate metabolic MRI in prostate cancer patients: Hyperpolarized Pyruvate Prostate Cancer Analysis Methods

MRI using hyperpolarized (HP) carbon‐13 pyruvate is being investigated in clinical trials to provide non‐invasive measurements of metabolism for cancer and cardiac imaging. In this project, we applied HP [1‐13C]pyruvate dynamic MRI in prostate cancer to measure the conversion from pyruvate to lactate, which is expected to increase in aggressive cancers. The goal of this work was to develop and test analysis methods for improved quantification of this metabolic conversion.

Technique development of 3D dynamic CS-EPSI for hyperpolarized 13C pyruvate MR molecular imaging of human prostate cancer: Chen et al.

The purpose of this study was to develop a new 3D dynamic carbon‐13 compressed sensing echoplanar spectroscopic imaging (EPSI) MR sequence and test it in phantoms, animal models, and then in prostate cancer patients to image the metabolic conversion of hyperpolarized [1‐13C]pyruvate to [1‐13C]lactate with whole gland coverage at high spatial and temporal resolution.