Figure 1.

(a) Sample ECG trace of a single cardiac cycle depicting the trigger signals of ECG, acoustic sensor (ACT) and pulse oximeter (POX), and the four examined cardiac phases: early systole, end-systole, early diastole and diastasis. (b–e) Voxel positioning is shown on (b) 2-chamber, (c) 4-chamber, (d) apical short-axis and (e) basal short-axis cine localizer MR images. (f–i) Central short-axis cine images acquired at the four distinct cardiac phases according to the ECG trace ((f) early systole, (g) end-systole, (h) early diastole, (i) diastasis) visualize the extent of cardiac contraction. (j) ³¹P spectra of the untriggered and (k–n) the four triggered scans corresponding to the short-axis images (f–i) above. Voxel positions are color-encoded as depicted in the legend. Metabolite resonances of PCr, $\alpha$- and $\gamma$-ATP, 2,3-DPG and PDE are well resolved in all spectra and even the P_i resonance can be detected in most of the individual single-voxel spectra.