Metabolic Imaging of the Heart Using Hyperpolarized (13C) Pyruvate Injection

For this study, the heart of control subjects and those with hypertension or hypertrophy will be imaged using Hyperpolarized Pyruvate 13C Injection. Different forms of Hyperpolarized Pyruvate 13C Injection are available, with the 13C labelling at different positions within the molecule. These are equivalent from a safety perspective and covered by the same Investigators Brochure, but offer different metabolic information. Two different labelling patterns are investigated in this study. If images are successfully obtained, then insights into heart failure treatments that normalize the detrimental metabolic changes may enable earlier treatment and slow disease progression to CHF, ultimately reducing the high rates of morbidity and mortality associated with this disease.

Prior to enrollment, all participants will be screened in order to ensure they meet the study's inclusion and exclusion criteria and MRI eligibility. On the day of their scan, each participant will have an intravenous line inserted and receive a glucose drink, prior to scanning. The reason for this glucose drink is that a fed versus fasted state has been found to give markedly different measurements in animal models and a choice of meal would be a source of variability. The metabolic imaging will occur shortly after this drink.

For each scan, a 1.47 g sample of [1-13C]-pyruvic acid will be hyperpolarized using a SpinLab polarizer (General Electric Co.). The solid-state sample will be dissolved to a concentration of 250 mM pyruvate at biological pH. A 0.1 mmol/kg dose (approximately 20 mL) of this solution will be injected through an intravenous line, followed by a 25 mL saline flush. The 13C image acquisition will begin at the end of the injection and will record data during every heartbeat within the single breath-hold.

Heart rate and blood pressure will be monitored non-invasively, prior to the participant being positioned within the MR scanner. Heart rate will continue to be monitored during and after the scan and the participant will be monitored by the Study's Qualified Investigator or medical designate for up to 1 hour post injection.

The 13C imaging will be preceded by the standard cardiovascular MRI workup including breath-hold cine imaging to measure ejection fraction and LV mass (~30 minutes of scan time).