The overall goal of this research is to develop a quantitative Magnetic Resonance Imaging (MRI) approach of oxygen utilization that provides a non-invasive and effective imaging test for the assessment of myocardial infarction. According to the most recent Heart Disease and Stroke Statistical Update (2015) published by the American Heart Association, almost 1 out of every 3 deaths in the United States (US) is caused by cardiovascular diseases that include coronary artery disease (CAD) every year. Over $40 billion is spent on cardiac stress tests each year, and nearly 1.5 million individuals are undergo percutaneous coronary intervention or coronary artery bypass surgery to treat severe CAD after nuclear stress test screening. However, the occurrence of obstructive CAD found during invasive stenting/pre-surgical coronary X-ray angiography is less than 40%. The current screening paradigm is expensive, exposes patients to ionizing radiation, and carries additional risks of intimal injury and acute vessel dissection. Cardiac Magnetic Resonance Imaging is a non-invasive imaging modality that currently is the gold standard for the quantitative assessment of ventricular function and myocardial viability evaluation. In particular, LGE can assess viable or non-viable myocardial tissue by interrogating the delayed response to gadolinium-based contrast agent administration. While this LGE assessment is robust, this reference evaluation leaves no room for further improvements via scan-time reduction, and forces any further quantification of underlying tissue pathophysiology to be obtained as separate scans that prolong each patient exam. Accordingly, the 30-plus minute LGE-CMR exam with contrast injection is the widely established, and definitive state-of-art. The scientific premise for this research is that MRI of oxygen utilization provides correlative information on the extent of viable or non-viable tissue without contrast injection. We hypothesize that a non-contrast MR quantification of oxygen utilization in less than one minute of additional scan-time to current routine cardiac MR protocol may offer a new paradigm-shifting, fast alternative evaluation of myocardial infarctions without the need for contrast injection. Hence, we aim to: 1) develop the pulse sequence and advanced image reconstruction methods to quantify myocardial oxygen utilization; 2) validate this method in the patient cohort, and 3) evaluate the proposed cardiac MRI evaluation in a single-center patient imaging setting over a 3-year span in two subject cohorts. The outcome of this work is not only the scientific findings pertaining to the feasibility of the proposed MRI method, but also the compilation of an extensive 200-patient database including all quantitative study measurements of the state-of-the-art MRI evaluations, patient data including outcomes, as well as findings from other modalities such as x-ray catheter (and echo) if these are also performed.
Cardiovascular disease is currently the leading cause of death in the United States and around the world, which affects ~91 million individuals in the United States. We propose to develop an effective imaging test method using magnetic resonance imaging (MRI) to better detect for infarction by directly mapping oxygen utilization in the heart?s myocardium. The proposed approach does not need for contrast agent injections, nor adds significant additional scan times over the currently used non-contrast CMR protocols. This approach will add value to existing cardiac cine-CMR by also obtaining two quantitative measures including oxygen utility that we hypothesize would correlate with the presence of myocardial infarction.
