Biography – Research in Dr. Daniel Ennis’s lab principally focuses on developing MRI methods to quantitatively explore cardiac structure, function, flow, and remodeling. Dr. Ennis became interested in cardiac biomechanics as an undergraduate at the University of California, San Diego (UCSD) where he earned his B.S. in Bioengineering (1997). Subsequently, he attended Johns Hopkins University, where he received a Ph.D. in Biomedical Engineering (2004), specializing in cardiac magnetic resonance imaging. During that time he also worked at the National Institutes of Health (NIH) in the Laboratory of Cardiac Energetics. He then completed a post-doctoral fellowship in the departments of Radiology and Cardiothoracic Surgery at Stanford University, where he more deeply explored both MRI physics and cardiac mechanics (2008). He moved to UCLA as Assistant Professor and shortly thereafter helped start the Magnetic Resonance Research Labs. He established close collaborations with the Division of Cardiology and continued to develop advanced cardiac MRI methods, explore cardiac microstructure, and develop methods for integrating detailed imaging data into computational models of cardiac electrophysiology and mechanics. Since 2018 he has run the Cardiac Magnetic Resonance Group at Stanford University in the Department of Radiology. His group continues to develop cardiac MRI methods to explore cardiac structure, function, flow, and remodeling, with an emphasis on quantitative imaging biomarkers of early disease. He also works closely with cardiothoracic surgeons and bioengineers to invent and develop next generation approaches to treating cardiovascular disease through advanced imaging and simulation.
Abstract – Cardiac structure is inextricably bound to cardiac function. Much of what we have recently learned arises from advances in cardiac MRI methods that better enable quantifying regional changes in both micro-structure and micro-function. This talk will begin by discussing the most current descriptions of myocardial micro-architecture spanning cellular to whole-heart scales. In doing so, both micro-structural and micro-functional characteristics of deforming myocardium will be described. These relatively new MRI methods that enable characterizing in vivo micro-structural organization (i.e. “myofiber” orientation) and micro-function (i.e. “myofiber” strain) will also be described. In vivo micro-structural organization is captured by using diffusion-based MRI methods adapted to capture the subtle motion of diffusing water in the rapidly beating heart. When coupled with cardiac MRI methods that encode three-dimensional tissue displacement we can build integrated structure-function computational models to estimate “myofiber” strains. When coupled together these methods potentially provide more mechanistic insight to cardiac function and dysfunction than, for example, ejection fraction.