Hyperpolarized 13C Metabolic MRI of the Human Heart: Initial Experience.

RATIONALE: Altered cardiac energetics is known to play an important role in the progression toward heart failure. A noninvasive method for imaging metabolic markers that could be used in longitudinal studies would be useful for understanding therapeutic approaches that target metabolism.

OBJECTIVE: To demonstrate the first hyperpolarized 13 C metabolic magnetic resonance imaging of the human heart.

METHODS AND RESULTS: Four healthy subjects underwent conventional proton cardiac magnetic resonance imaging followed by 13 C imaging and spectroscopic acquisition immediately after intravenous administration of a 0.1 mmol/kg dose of hyperpolarized [1-13 C]pyruvate. All subjects tolerated the procedure well with no adverse effects reported ≤1 month post procedure. The [1-13 C]pyruvate signal appeared within the chambers but not within the muscle. Imaging of the downstream metabolites showed 13 C-bicarbonate signal mainly confined to the left ventricular myocardium, whereas the [1-13 C]lactate signal appeared both within the chambers and in the myocardium. The mean 13 C image signal:noise ratio was 115 for [1-13 C]pyruvate, 56 for 13 C-bicarbonate, and 53 for [1-13 C]lactate.

CONCLUSIONS: These results represent the first 13 C images of the human heart. The appearance of 13 C-bicarbonate signal after administration of hyperpolarized [1-13 C]pyruvate was readily detected in this healthy cohort (n=4). This shows that assessment of pyruvate metabolism in vivo in humans is feasible using current technology.

CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02648009.