title: Mechanistic insight into the physiological relevance of helical blood flow in the human aorta: an in vivo study.
abstract: The hemodynamics within the aorta of five healthy humans were investigated to gain insight into the complex helical flow patterns that arise from the existence of asymmetries in the aortic region. The adopted approach is aimed at (1) overcoming the relative paucity of quantitative data regarding helical blood flow dynamics in the human aorta and (2) identifying common characteristics in physiological aortic flow topology, in terms of its helical content. Four-dimensional phase-contrast magnetic resonance imaging (4D PC MRI) was combined with algorithms for the calculation of advanced fluid dynamics in this study. These algorithms allowed us to obtain a 4D representation of intra-aortic flow fields and to quantify the aortic helical flow. For our purposes, helicity was used as a measure of the alignment of the velocity and the vorticity. There were two key findings of our study: (1) intra-individual analysis revealed a statistically significant difference in the helical content at different phases of systole and (2) group analysis suggested that aortic helical blood flow dynamics is an emerging behavior that is common to normal individuals. Our results also suggest that helical flow might be caused by natural optimization of fluid transport processes in the cardiovascular system, aimed at obtaining efficient perfusion. The approach here applied to assess in vivo helical blood flow could be the starting point to elucidate the role played by helicity in the generation and decay of rotating flows in the thoracic aorta.
authors.affiliation: Department of Mechanics, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy. umberto.morbiducci@polito.it
authors.forename: Umberto
authors.initials: U
authors.lastname: Morbiducci
authors.forename: Raffaele
authors.initials: R
authors.lastname: Ponzini
authors.forename: Giovanna
authors.initials: G
authors.lastname: Rizzo
authors.forename: Marcello
authors.initials: M
authors.lastname: Cadioli
authors.forename: Antonio
authors.initials: A
authors.lastname: Esposito
authors.forename: Franco Maria
authors.initials: FM
authors.lastname: Montevecchi
authors.forename: Alberto
authors.initials: A
authors.lastname: Redaelli
mesh_terms: D000328:Adult; D000465:Algorithms; D001011:Aorta / Q000502:physiology*; D001696:Biomechanical Phenomena / Q000502:physiology; D001775:Blood Circulation / Q000502:physiology*; D003287:Contrast Media; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D013997:Time Factors; D055815:Young Adult
chemical_list: D003287:Contrast Media