Simultaneous noninvasive determination of regional myocardial perfusion and oxygen content in rabbits: Toward direct measurement of myocardial oxygenconsumption at MR imaging

PURPOSE: To determine whether myocardial arterial perfusion and oxygen conc entration can be quantified simultaneously from the same images by using sp in labeling and the blood oxygenation level-dependent (BOLD) effect with fa st spin-echo (SE) imaging. MATERIALS AND METHODS: A T2-weighted fast SE pulse sequence was written to image isolated, arrested, blood-perfused rabbit hearts (n = 6) at 4.7 T Per fusion images with intensity in units of milliliters per minute per gram th at covered the entire left ventricle with 0.39 x 0.39 x 3.00-mm resolution were obtained in less than 15 minutes with a 32-fold reduction in imaging t ime from that of a previous study. Estimates of oxygen concentration were m ade from the same images acquired for calculation of perfusion images. RESULTS: Estimates of regional myocardial oxygen content could be made from the,perfusion images; this demonstrated the feasibility of three-dimension al calculation of regional oxygen consumption, which requires concomitant m easurement. of both oxygen content and flow. Fast SE imaging was shown to b e as sensitive to hemoglobin desaturation as standard SE imaging. Perfusion abnormalities and oxygen deficits were easily identified and verified qual itatively with gadopentetate dimeglumine on both perfusion and BOLD images obtained after coronary arterial ligation. CONCLUSION: T2-weighted fast SE imaging combined with perfusion-sensitive s pin labeling can be used to measure myocardial arterial perfusion and oxyge n concentration. This provides the groundwork for calculation of regional m yocardial oxygen consumption.