UC San Diego

Assessment of regional cardiac function has implications in the diagnosis and management of cardiac diseases such as myocardial ischemia, heart failure, dyssynchrony, and cardiotoxicity. Over the past 30 years, significant effort has been focused on developing methods for measuring regional cardiac function; however, there remains an urgent unmet clinical need for a method that is easily available, accurate, reproducible, and operator independent. Modern four-dimensional computed tomography (4DCT) imaging systems can acquire full heart volume, 1 x 1 x 1 mm^3 voxel cardiac images spanning the entire cardiac cycle from a single table position and within a single heartbeat; no other non-invasive cardiac imaging modality comes close to this capability. The images have very high spatial resolution and are now routinely acquired with ultra-low exposure to ionizing radiation. In this proposal, we aim to leverage the advancements in 4DCT technology and develop methods that yield accurate and reproducible high-resolution estimates of regional cardiac function. First, we develop anthropomorphically accurate phantoms of the human left ventricle (LV) and use these phantoms as ground-truth in the development and optimization of methods for the assessment of regional LV strains with high spatial resolution. Second, we use the developed phantoms to understand and improve the temporal resolution of 4DCT; the accurate and reproducible estimation of the timing of LV mechanics has been shown to be a very important feature in predicting patient response to cardiac resynchronization therapy (CRT). Third, we apply the developed methods to cohorts of routinely acquired clinical 4DCT scans and investigate the potential effect of the developed 4DCT methods in the diagnosis and management of cardiac diseases, using CRT as an example. In conclusion, this dissertation has broadened our understanding of the spatio-temporal resolution of 4DCT and potentially fulfils the unmet clinical need for a highly accurate and reproducible method to estimate regional cardiac function.