Three dimensional echo-planar imaging at 7 Tesla.
Neuroimage
; 51(1): 261-6, 2010 May 15.
Article
en En
| MEDLINE
| ID: mdl-20139009
Functional MRI (fMRI) most commonly employs 2D echo-planar imaging (EPI). The advantages for fMRI brought about by the increasingly popular ultra-high field strengths are best exploited in high-resolution acquisitions, but here 2D EPI becomes impractical for several reasons, including the very long volume acquisitions times. In this study at 7 T, a 3D EPI sequence with full parallel and partial Fourier imaging capability along both phase encoding axes was implemented and used to evaluate the sensitivity of 3D and corresponding 2D EPI acquisitions at four different spatial resolutions ranging from small to typical voxel sizes (1.5-3.0 mm isotropic). Whole-brain resting state measurements (N=4) revealed a better, or at least comparable sensitivity of the 3D method for gray and white matter. The larger vulnerability of 3D to physiological effects was outweighed by the much shorter volume TR, which moreover allows whole-brain coverage at high resolution within fully acceptable limits for event-related fMRI: TR was only 3.07 s for 1.5 mm, 1.88 s for 2.0 mm, 1.38 s for 2.5 mm and 1.07 s for 3.0 mm isotropic resolution. In order to investigate the ability to detect and spatially resolve BOLD activation in the visual cortex, functional 3D EPI experiments (N=8) were performed at 1 mm isotropic resolution with parallel imaging acceleration of 3x3, resulting in a TR of only 3.2 s for whole-brain coverage. From our results, and several other practical advantages of 3D over 2D EPI found in the present study, we conclude that 3D EPI provides a useful alternative for whole-brain fMRI at 7 T, not only when high-resolution data are required.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Encéfalo
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Mapeo Encefálico
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Imagen por Resonancia Magnética
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Imagen Eco-Planar
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Imagenología Tridimensional
Límite:
Humans
Idioma:
En
Revista:
Neuroimage
Asunto de la revista:
DIAGNOSTICO POR IMAGEM
Año:
2010
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Estados Unidos