Fig. 2

Example cardiac spectra acquired from the 6^th slice of 1DCSI setup illustrated in Fig. 1. a 9 min acquisition without any saturation used to determine M₀ from the peak height of the PCr peak. This spectrum is also used to determine the saturation frequency of the γ-ATP peak in the heart. b 9 min acquisition with control saturation at the frequency indicated by the black arrow used to determine M₀ ^control. c 22 min acquisition with γ-ATP saturation (black arrow) and long TR used to determine M₀` in the TwiST experiment, and M`(TR_long) in the TRiST experiment. d This 9 min acquisition is only used in TRiST but not in TwiST. It is acquired with γ-ATP saturation (black arrow) and short TR and used to determine M`(TR_short). TwiST uses acquisitions shown in b) and c); TRiST uses acquisitions shown in b), c), and d); Q-corrected TwiST uses acquisitions shown in a), b), and c); and Q-corrected TRiST uses acquisitions shown in a), b), c), and d)