Quantifying Myocardial Oxygenation with Cardiac Magnetic Resonance Imaging

Myocardial ischemia, resulting from imbalance in myocardial oxygen supply and demand, can be quantitatively assessed by positron emission tomography (PET) with absolute measures of myocardial blood flow and oxygen consumption rate (MVO2). Cardiac Magnetic Resonance (CMR) has notable advantages over PET, with no radiation, high spatial resolution, faster scan times, and excellent soft tissue contrast. We have developed and validated new quantitative CMR oximetry techniques, including measurements of hyperemic myocardial oxygen extraction fraction and MVO2 through Fick’s Law. These may lead to a new understanding of roles of myocardial microcirculation in myocardial ischemia. Other cardiac oximetry methods for directly quantifying MVO2 with O-labelled water are also under investigation. Quantitative CMR oximetry is a promising, non-invasive, non-radiation approach for exploring the myocardial metabolism’s role in cardiac patients.