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Titolo:
Visualization of flow patterns distal to aortic valve prostheses in humansusing a fast approach for cine 3D velocity mapping
Autore:
Kozerke, S; Hasenkam, JM; Pedersen, EM; Boesiger, P;
Indirizzi:
Univ Zurich, Inst Biomed Engn, CH-8092 Zurich, Switzerland Univ Zurich Zurich Switzerland CH-8092 Engn, CH-8092 Zurich, Switzerland
Titolo Testata:
JOURNAL OF MAGNETIC RESONANCE IMAGING
fascicolo: 5, volume: 13, anno: 2001,
pagine: 690 - 698
SICI:
1053-1807(200105)13:5<690:VOFPDT>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
BLOOD-FLOW; HEART-VALVES; DOWNSTREAM; MRI; BIFURCATION; REDUCTION; FIELDS;
Keywords:
MRI; velocity mapping; three-dimensional visualization; heart valve prosthesis; aortic flow;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
23
Recensione:
Indirizzi per estratti:
Indirizzo: Boesiger, P Univ Zurich, Inst Biomed Engn, Gloriastr 35, CH-8092 Zurich, Switzerland Univ Zurich Gloriastr 35 Zurich Switzerland CH-8092 itzerland
Citazione:
S. Kozerke et al., "Visualization of flow patterns distal to aortic valve prostheses in humansusing a fast approach for cine 3D velocity mapping", J MAGN R I, 13(5), 2001, pp. 690-698

Abstract

The fluid dynamic performance of mechanical heart valves differs from normal valves and thus is considered related to late clinical complications in patients. Since flow patterns evolving around heart valves are complex In space and time, flow visualization based on time-resolved 3D velocity data might add important information regarding the performance of specific valve designs In vivo. However, previous cine 3D techniques for three-directionalphase-contrast velocity mapping suffer from long scan duration and therefore might hamper assessment In patients. A hybrid 3D phase-contrast sequencecombining segmented k-space acquisition with short EPI readout trains is presented with its validation in vitro. The technique was applied to study flow patterns downstream from a bileaflet aortic prosthesis in six patients. Navigator echoes were incorporated for respiratory motion compensation. Before flow visualization, spurious phase errors due to concomitant gradient fields and eddy currents were corrected. Flow visualization was based on particle paths and animated velocity vector plots. Dedicated algorithms for particle path Integration were implemented to account for the considerable motion of the ascending aorta during the cardiac cycle. A distinct flow pattern reflecting the valve design was observed closest to the valve during early flow acceleration. Reverse flow occurred adjacent to high velocity jetsand above the hinge housings. Later in systole, flow became confined to the central vessel area and reverse flow along the inner aortic curvature developed. Further downstream from the valve, flow patterns varied considerably among patients, Indicating the impact of varying aortic anatomy In vivo. It Is concluded that MR velocity mapping is a potential tool for studying 3D flow patterns evolving around heart valve prostheses in humans. (C) 2001 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/01/20 alle ore 10:15:43