Phase-dependent variation in cardiac metabolism assessed with hyperpolarized [1-13C]pyruvate

Motivation: A bolus injection of the hyperpolarized pyruvate may affect heart rate, potentially causing a fixed trigger delay setup to miss signals from the targeted cardiac phase. Goal(s): To develop a retrospective compensation algorithm for dynamic cardiac 13C MRS by utilizing a phase-dependent simulation. Approach: Hemodynamic response of the heart to bolus injected pyruvate was simulated. The feasibility of the retrospective compensation method was tested using human cardiac data in vivo. Results: Time-resolved 13C MR spectroscopy, acquired from healthy subjects without a cardiac gating, could be properly assessed retrospectively using recorded heart rate and corresponding structural cine images Impact: By utilizing structural Cine images alongside heart rate records, a retrospectively reconstructing algorithm was developed for restoring the ideal input function despite the cardiac phases. This method enhanced the precision of cardiac MRS in HP MRI.