Valvular and coronary blood flow quantification by cardiac 4D flow MRI

Abstract

Unlike X-ray, CT, PET and SPECT, which image body tissues based on their interaction with ionizing radiation, MRI exploits the tissues’ interaction with a magnetic field and radio waves. It does so non-invasively, without harming the body, and has become a popular imaging technique in hospitals all over the world. Not only does it allow for the imaging of tissues, it can also measure blood flow velocities, making it a useful technique for the assessment of cardiac disease. Currently, MRI-based assessment of cardiac hemodynamics largely relies on 2D flow MRI, which can characterize blood flow in two-dimensional imaging planes over time. 4D flow MRI offers three-dimensional velocity measurement over time.This thesis concerns the innovation and validation of cardiac 4D flow MRI for blood flow quantification in valvular heart disease and coronary artery disease. We1) review various 4D flow MRI-derived hemodynamic parameters, together with their diagnostic and prognostic potential for the evaluation of left-sided valvular heart disease,2) investigate the potential of an analysis technique called flow tracking for 4D flow MRI-based quantification of mitral valve regurgitation (i.e. leakage),3) compare two accelerated whole-heart 4D flow MRI techniques for quantification of normal and regurgitant blood flow across the heart valves,4) evaluate a novel, camera-based technique for respiratory motion monitoring and gating in whole-heart 4D flow MRI, and5) present a framework for coronary blood flow quantification using accelerated 4D flow MRI equipped with respiratory motion correction.<br/