Simultaneous non-invasive determination of regional myocardial perfusion and oxygen content

Assessment of regional myocardial oxygen consumption remains an important objective in the evaluation of ischemic heart disease, since the ability to consume oxygen is an indicator of tissue viability. Exploiting the blood oxygenation level dependent (BOLD) effect with T₂ weighted spin echo magnetic resonance (MR) imaging, we have previously reported estimation of regional myocardial oxygen content. We have also reported quantitative estimation of arterial myocardial perfusion using MR spin-labeling. In this work, a fast spin echo pulse sequence was writen to image isolated, arrested blood-perfused rabbit hearts at 4.7T. Perfusion images (where image intensity was directly related to arterial How in mL/min/g) were obtained in 15 minutes, covering the entire heart with a resolution of 0.39 × 0.39 × 3 mm³. Estimates of regional myocardial oxygen content were made from the same images acquired for the perfusion measurements, by T₂-weighting the image acquisitions. This demonstrates the feasibility of non-invasive calculation of three-dimensional regional oxygen consumption in the heart using magnetic resonance imaging. Both perfusion abnormalities and oxygen deficits were easily identified in perfusion and BOLD images obtained after ligation of the left anterior descending coronary artery. Although the current study was performed in the arrested heart preparation, it provides the framework for calculation of regional myocardial oxygen consumption in the intact, beating heart preparation.