All ETDs from UAB

Advisory Committee Chair

Steven G Lloyd

Advisory Committee Members

Thomas S Denney

Ho-Wook Jun

Jack Lemons

Sumanth Prabhu

Document Type

Dissertation

Date of Award

2023

Degree Name by School

Doctor of Philosophy (PhD) School of Engineering

Abstract

Magnetic resonance imaging (MRI) has proven invaluable for clinical and research investigations due to its minimal invasiveness and excellent measurement precision and reproducibility. In particular, Cardiac MRI (CMR) is a powerful tool for evaluating anatomical and functional properties of the left ventricle (LV). In this study, two aspects of CMR applications of the LV are investigated: 1) assessment of diastolic function by quantifying LV stiffness index and related properties as a representation of intrinsic myocardium properties in patients with diastolic dysfunction and 2) evaluation of systolic function by relating myocardial strain and LV geometrical configuration with ejection fraction (EF). The central hypothesis is that myocardial strain and geometrical deformation derived from CMR can provide relevant and comprehensive information to assess LV systolic and diastolic function based on fundamental principles of motion and mechanics of biological materials and help understand physical conditions that can affect LV function. The aims of this study are 1) Derived LV stiffness indices of LV based on geometric factors and its untwisting motion using data from tag/cine CMR and validate the data using a well-accepted index for diastolic stiffness; 2) Perform a comprehensive study of compensatory factors in LV by using data obtained from tag/cine CMR. This proposed study is innovative since 1) Diagnosis of diastolic dysfunction is challenging; cardiac catheterization remains the “gold standard” for demonstrating impaired LV relaxation, but the balance of risk and cost compared to the potential benefit of catheterization argues against its routine use in clinic. Non-invasive imaging, such as echocardiography or MRI, is now used to identify and grade diastolic dysfunction. However, these non-invasive methods still have some limitations and beg for a newer approach. Our study will allow for a non-invasive and load-independent evaluation of diastolic function; 2) Understanding the contribution of strains and geometry to LV systolic function reinforces the idea that reliance on EF only may mask changes that can be an initial sign of early systolic function deterioration. This contribution is significant because it will facilitate a better understanding of LV functional assessment, leading to better identification and treatment of patients with heart muscle disease.

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Engineering Commons

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