Ultrafast Flow Quantification With Segmented k-Space Magnetic Resonance Phase Velocity Mapping

Noninvasive quantification of fluid mechanical energy losses in the total cavopulmonary connection with magnetic resonance phase velocity mapping

“…This is very important considering the large difference in the number of slices necessary to image the region of interest in both models (20 transverse vs. 3 coronal in the tube; 36 transverse vs. 3 coronal in the TCPC). Currently, the scan time for ECGgated acquisitions of three slices with all velocity components is 3-10 min depending on the degree of k-space segmentation [37,38]; the scan time would be 15-30 min for 20 slices and more than 35 min for 36 slices, making the clinical implementation of the method imprac tical and unappealing.…”

Anteil des frühen systolischen Flussanstiegs am antegrad fließenden Gesamtvolumen bei Phasenkontrast-Flussmessungen in Atemanhaltetechnik

“…Flussquantifizierungen mit Hilfe segmentierter atemangehaltener Phasenkontrast-Sequenzen stimmen sowohl mit 7 als auch mit 9 "number of views per segment" (NVS) und Anwendung von Phase sharing gut mit den Ergebnissen der nicht-segmentierten Flussmessung bei freier Atmung überein [24,34]. Die Rekonstruktion von mehr als 10 bis 16 Cine-Frames pro Herzzyklus verbesserte die Genauigkeit einer Phasenkontrast-Messung mit 8 k-Raum Zeilen pro Segment und einstellbarem Grad des Viewsharing nicht [14].…”

Blood flow measurements with magnetic resonance phase velocity mapping

“…If velocity-encoding gradients are added to the regular sequence, the flow velocity can be measured rapidly. Systematic in vitro [65,66] and in vivo [67] studies have shown that segmented k-space MR PVM is very accurate in quantifying flow from through-plane velocity measurements, under a variety imaging parameters. The in vitro study involved flow quantification from throughplane velocity data in straight tubes, under a vari ety of steady and pulsatile flow conditions.…”

“…The in vitro study involved flow quantification from throughplane velocity data in straight tubes, under a vari ety of steady and pulsatile flow conditions. The effect of the number of k-space lines per segment was studied by examining the unsegmented se quence and three segmented k-space schemes, with five [65], seven [66] and nine [65] k-space lines per segment. Results showed that both segmented se quences provided very accurate flow quantifica tion (errors < 5%) under both steady and pulsatile flow conditions (p-value 0.05).…”