4D flow imaging with 2D-selective excitation.
Magn Reson Med
; 82(3): 886-900, 2019 09.
Article
en En
| MEDLINE
| ID: mdl-31002417
ABSTRACT
PURPOSE:
4D flow MRI permits to quantify non-invasively time-dependent velocity vector fields, but it demands long acquisition times. 2D-selective excitation allows to accelerate the acquisition by reducing the FOV in both phase encoding directions. In this study, we investigate 2D-selective excitation with reduced FOV imaging for fast 4D flow imaging while obtaining correct velocity quantification.METHODS:
Two different 2D-selective excitation pulses were designed using spiral k-space trajectories. Further, their isophase time point was analyzed using simulations that considered both stationary and moving spins. On this basis, the 2D-selective RF pulses were implemented into a 4D flow sequence. A flow phantom study and seven 4D flow in vivo measurements were performed to assess the accuracy of velocity quantification by comparing the proposed technique to non-selective and conventional 1D slab-selective excitation.RESULTS:
The isophase time point for spiral 2D-selective RF pulses was found to be located at the end of excitation for both stationary and moving spins. Based on that, 2D-selective excitation with reduced FOV allowed us to successfully quantify velocities both in a flow phantom and in vivo. In a flow phantom, the velocity difference Δv¯=0.8±5.3cm/s between the smaller reduced FOV and the reference scan was similar to the inter-scan variability of Δv¯=-1.0±2.3cm/s . In vivo, the differences in flow (P = 0.995) and flow volume (P = 0.469) between the larger reduced FOV and the reference scan were non-significant. By reducing the FOV by two-thirds, acquisition time was halved.CONCLUSION:
A reduced field-of-excitation allows to limit the FOV and therefore shorten 4D flow acquisition times while preserving successful velocity quantification.Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Velocidad del Flujo Sanguíneo
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Imagen por Resonancia Magnética
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Imagenología Tridimensional
Límite:
Adult
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Magn Reson Med
Asunto de la revista:
DIAGNOSTICO POR IMAGEM
Año:
2019
Tipo del documento:
Article
País de afiliación:
Alemania