ter Keurs, Henk E.D.J.Friedrich, MatthiasLuu, Judy Mai2015-04-202015-06-222015-04-202015http://hdl.handle.net/11023/2147Cardiovascular disease remains a significant cause of premature death and disability in developing nations, with an increasing need for early and accurate diagnosis to limit downstream adverse events. By exploiting intracapillary deoxygenated haemoglobin to generate its signal, oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) or commonly referred to as Blood-Oxygen Level Dependent CMR (BOLD-CMR), is a non-invasive imaging technique that does not require contrast agents or radiation. Therefore, the purpose of this thesis was to build upon the understanding of myocardial oxygenation using CMR in the assessment of ischemic heart disease. By studying a population that included 34 patients with coronary artery, 32 participants with only coronary risk factors but no established clinical disease, and 11 young, healthy volunteers, we demonstrated that the OS-CMR signal intensity percent changes (∆SI%) in response to adenosine-induced vasodilation may be a function of both advancing age and decreasing diastolic blood pressure. Furthermore, for the first time, we showed differential features of ∆SI% in the distinctive layers of myocardium using OS-CMR, whereby ∆SI% was much less in the subendocardium compared to the subepicardium in both patients with coronary artery disease (CAD) and in individuals with only risk factors for cardiovascular disease. From there, we compared this imaging approach to the reference standard of fractional flow reserve (FFR) in 37 patients with suspected or known CAD. OS-CMR did identify abnormal myocardium supplied by coronary arteries with hemodynamically limiting stenoses, confirming a role for OS-CMR in the evaluation of myocardial ischemia. Complementary comparisons of OS-CMR to the measures of stenosis diameter by QCA and myocardial perfusion by CMR showed weaker correlations. Finally, in 34 patients with stable CAD, we sought to determine the impact of revascularization plus medical therapy (n=10 patients) versus medical therapy alone (n= 24 patients) on myocardial oxygenation at one-month follow-up. We demonstrated evidence to suggest that percutaneous coronary intervention (PCI) plus medical therapy may increase myocardial oxygenation as measured by OS-CMR. Conversely, patients treated with medical therapy exhibited reduced ∆SI% at the repeat scan, which was most profound in the subendocardium. Overall, our results suggest that OS-CMR measures of myocardial oxygenation may reflect alterations or dysfunction of the microcirculation and its vasodilatory capacity to compensate in the face of increasing oxygen demands, which may potentially be used as a marker for myocardial ischemia. Further research is needed to demonstrate the prognostic role of OS-CMR in the long-term.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Health SciencesCardiovascular Magnetic Resonance ImagingIschemic heart diseaseOxygenation-sensitive imagingdoctoral thesis10.11575/PRISM/27116