Quantifying cardiac blood flow and function in coronary artery disease

Coronary artery disease (CAD) remains the leading cause of death, accounting for 16% of global mortality. CAD results from progressive build-up of atherosclerotic plaque in the coronary vasculature, a process which is accelerated in the presence of cardiovascular risk factors such as dyslipidemia, smoking, hypertension, diabetes mellitus and chronic kidney disease. CAD is chronic, most often progressive, and dynamic in nature meaning that clinically silent periods are interspersed with acute events. Clinicians challenged with the task of diagnosing and treating this vast but heterogenous group of patients have a continuously expanding armamentarium of diagnostic modalities at their disposal. The majority of these techniques aims to answer one of two fundamental questions. First, is myocardial blood flow impaired to such an extent that obstructive CAD can be held accountable for the patients symptoms or that revascularization provides prognostic benefit? Second, to what extent is cardiac function impaired and how does this affect the patients prognosis? Each technique suffers from its own shortcomings, making appropriate selection not only dependent on the accuracy and precision of the technique but also on the clinical scenario, availability and invasive nature of the technique. The ideal technique is widely available, low-cost, non-invasive and provides the clinician with physiological as well as prognostic information. In addition, it serves as a guide for therapeutic management. Unfortunately, this ideal technique yet remains an elusive dream. The aim of this thesis was to improve diagnostic assessment of patients with stable CAD as well as acute coronary syndromes. In the first part of the thesis, several invasive and non-invasive techniques for quantifying coronary blood flow and myocardial perfusion are investigated. In the second part of the thesis, state-of-the-art techniques for quantification of cardiac function are explored.