Hyperpolarized Magnetic Resonance

Cardiovascular disease is associated with high morbidity, mortality, and financial burden to healthcare services.1–3 In the United States, cardiovascular disease is the leading cause of death in both men and women, accounting for 1 in every 2.9 deaths in 2006, with coronary disease accounting for 1 in every 6 deaths.2 Noninvasive cardiac imaging increasingly plays a fundamental role in diagnosing, assessing prognosis, and monitoring therapy response in cardiovascular disease.1,4,5 Two-dimensional echocardiography is the most commonly used imaging modality to measure heart function because of its low cost and widespread accessibility. Computed tomography (CT), single photon emission CT, and positron emission tomography (PET) expose patients to ionizing radiation but have been used successfully for clinical assessment of coronary arteries, myocardial perfusion, and viability, respectively. Cardiovascular magnetic resonance (CMR) applies no ionizing radiation and is now considered the gold standard in assessing cardiac anatomy, function, and mass.1 CMR has also shown great potential for evaluating perfusion and viability with gadolinium-based contrast agents.MR spectroscopy (MRS) and MR-based molecular imaging methods have shown promise for evaluating cardiac metabolism. For example, phosphorus-31 MRS assesses high-energy phosphate content and energy reserve in the human heart (reviewed elsewhere6). Other implementations of multinuclear MRS, including oxygen-17, carbon-13, sodium-23, and proton MRS, have described measurement of oxygen consumption,7 substrate selection, and rates of metabolic flux,8 postinfarct sodium accumulation,9 and lipid accumulation,10 respectively, in ex vivo and in vivo experimental models of disease. MR-based molecular imaging of particles labeled with fluorine-19 nuclei has been used to study tracer and drug pharmacokinetics and metabolism.11 Combined PET–MR imaging (MRI) methods have been demonstrated in preclinical and noncardiac applications to assess cardiac parameters in an infarct mouse model12 and for structural, functional, and molecular imaging …