Personalised modelling of the heart from 3D echocardiography and cardiac magnetic resonance imaging

Abstract

The morbidity and mortality associated with cardiovascular disease has steadily decreased owing to advances in patient care. Nevertheless, it prevails as the world’s leading cause of death, and is projected to remain as such into the future. Tools for early and accurate diagnosis of heart disease are therefore essential for the management of individual and population health. While magnetic resonance imaging remains the gold standard for non-invasive cardiac examination, it is greatly limited by high costs, inequitable access, and patient intolerance. In contrast, echocardiography presents as a portable and convenient alternative for rapid and accessible cardiac imaging. Although echocardiography has traditionally been a 2D modality, developments in ultrasonography have made 3D imaging possible. Since its inception, 3D echocardiography has been regarded as ‘revolutionary’—owing to its ability to capture cardiac anatomy in its entirety, and thus circumventing the need for geometric assumptions. Nevertheless, the analysis of 3D echocardiograms remains difficult due to the low spatial resolution, poor tissue contrast, and characteristic speckle noise. As a result, manual delineation of anatomic structures, where required, can be tedious and subjective. Considering these challenges, the objectives of this research were to: (i) compare indices derived from 3D echocardiography against those obtained using cardiac magnetic resonance imaging; (ii) devise a mapping function between geometries derived from the two imaging modalities; and (iii) develop an automated method for the analysis of 3D echocardiograms in an accurate and reproducible manner. The time-varying left ventricular geometries derived from 3D echocardiography in this work represent a step towards the ability to create personalised models of the heart from a widely accessible imaging modality—and a concerted effort across the disciplines of medical imaging, cardiology, and bioengineering, to better understand the mechanisms of the heart in disease and in health.