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Figure 2. Sensitive volumes positioned in an optimal orientation relative to the LV on the basis of A, transverse and B, sagittal spin-echo scout MR images. By using two-dimensional image-selected in vivo spectroscopy and one-dimensional chemical shift imaging (spectroscopic imaging), the one-dimensional phase-encoding bar, with 32 rows of 1-cm thickness each, is angulated around the caudocranial body axis perpendicular to the chest wall. In this way, chest wall muscle is excluded from the first row containing myocardial tissue, row 25. B, By adjusting the level of the volume selection in the caudocranial direction, contamination of the sensitive volumes by diaphragm muscle and liver tissue is prevented. A and B, The white square on the chest wall originates from a sample in the center of the 10-cm-diameter surface coil. C, Resulting 31P MR spectra are shown separately for each row. On the basis of strict criteria previously published (6), cardiac spectra were identified and summed to provide one 31P MR spectrum. The PCr-ATP ratio and an estimate of the noise percentage are shown on the right for each spectrum.
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