Hyperpolarized Pyruvate MRS in Pigs

The pigs were fed and received an oral glucose bolus (2 g/kg) 3.5 hours and 45 minutes before MRS, respectively. MRI and hyperpolarized [1-¹³C]pyruvate MRS were carried out at rest and under dobutamine-stress (10 µg/kg/min IV), which is used for mimicking exercise in the clinic^{36 (link)}. All examinations were carried out on a commercial 3 T MRI system (GE Healthcare). The [1-¹³C]pyruvate was hyperpolarized in a SPINLab polarizer (GE Healthcare)^{37 (link)}. At the start of pyruvate injection, 128 spectra were acquired. After post-processing^{38 (link)}, pyruvate to metabolite conversion was quantified using the area under the curve approach^{39 (link)}. Myocardial pH was estimated from the bicarbonate and lactate signals^{40 (link)}. Conventional MRI was analysed with segmentation and volume measures were normalised to body weight^{41 (link)}. The MRS stress data of one RVO animal and the stress data of one control animal were excluded due to equipment failure.