title: In vivo quantification of helical blood flow in human aorta by time-resolved three-dimensional cine phase contrast magnetic resonance imaging.
abstract: The mechanics of blood flow in arteries plays a key role in the health of individuals. In this framework, the role played by the presence of helical flow in the human aorta is still not clear in its relation to physiology and pathology. We report here a method for quantifying helical flow in vivo employing time-resolved cine phase contrast magnetic resonance imaging to obtain the complete spatio-temporal description of the three-dimensional pulsatile blood flow patterns in aorta. The method is applied to data of one healthy volunteer. Particle traces were calculated from velocity data: to them we applied a Lagrangian-based method for helical flow quantification, the Helical Flow Index, which has been developed and evaluated in silico in order to reveal global organization of blood flow. Our results: (i) put in evidence that the systolic hemodynamics in aorta is characterized by an evolving helical flow (we quantified a 24% difference in terms of the content of helicity in the streaming blood, between mid and early systole); (ii) indicate that in the first part of the systole helicity is ascrivable mainly to the asymmetry of blood flow in the left ventricle, joined with the laterality of the aorta. In conclusion, this study shows that the quantification of helical blood flow in vivo is feasible, and it might allow detection of anomalies in the expected physiological development of helical flow in aorta and accordingly, could be used in a diagnostic/prognostic index for clinical practice.
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: Francesco
authors.initials: F
authors.lastname: De Cobelli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Maschio
authors.forename: Franco Maria
authors.initials: FM
authors.lastname: Montevecchi
authors.forename: Alberto
authors.initials: A
authors.lastname: Redaelli
mesh_terms: D001011:Aorta / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D003198:Computer Simulation; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008955:Models, Cardiovascular; D011673:Pulsatile Flow / Q000502:physiology