Reconstruction of geometry and motion of the right heart for detailed computational haemodynamics

The right side of the heart has a fundamental role in several critical clinical situations. For this reason, understanding its function deeply is essential for preventing cardiovascular diseases, the leading cause of death worldwide. Moreover, the role of the right heart is pivotal in congenital heart diseases, where the right ventricle may act either as a subpulmonary or a systemic ventricle. An important example is the Tetralogy of Fallot, which involves the presence of a defect between the ventricles and an obstruction of the right ventricular outflow tract. This condition is typically corrected surgically in infancy with high success. However, complications such as Pulmonary Regurgitation can develop in adulthood, causing ventricular dilation and dysfunction. To prevent irreversible remodelling, pulmonary valve replacement - either surgical or percutaneous - is performed. Despite these clinical challenges, there is a lack of comprehensive studies on right heart function in both healthy and diseased conditions, highlighting a significant gap in current research. The goal of this thesis is to develop a procedure for conducting patient-specific computational studies of right heart haemodynamics in both healthy and pathological scenarios. Specifically, our aim is to propose an innovative technique for reconstructing the geometry and motion of the right heart from dynamic magnetic resonance imaging – the Multi-Series Morphing method. The displacement of the endocardial wall (including the right ventricle, atrium, and main pulmonary artery) and the right heart valves (tricuspid and pulmonary valves) obtained through this technique will be utilized in the computational fluid dynamics model. Through this model, we will approach the study of the healthy right heart haemodynamics, we will investigate the effects of severe pulmonary regurgitation on blood flow in an adult patient with Tetralogy of Fallot, and examine haemodynamic changes induced by the percutaneous pulmonary valve replacement. This thesis will present the following innovative aspects: - The introduction of a novel method for generating the right heart geometry and motion over the heartbeat from multiple cine-Cardiac Magnetic Resonance views. By suitable merging of different views, we aim at improving the reconstruction detail and accuracy, which are essential elements in view of employing the resulting cardiac displacement field in the generation of computational fluid dynamics models; - The introduction of complete dynamic image-based computational fluid dynamics models, including all the right heart structures (ventricle, atrium, main pulmonary artery, tricuspid and pulmonary valves), to provide a comprehensive understanding of the healthy and pathological haemodynamics; - Exploring the potentiality of the proposed computational model, we aim at improving the understanding of the Tetralogy of Fallot, analysing in detail the haemodynamic in the presence of pulmonary regurgitation and the changes induced by the pulmonary valve replacement in adult patients.