Diffusion tensor parameters and principal eigenvector coherence: relation to b-value intervals and field strength.
Magn Reson Imaging
; 31(5): 742-7, 2013 Jun.
Article
en En
| MEDLINE
| ID: mdl-23375836
ABSTRACT
Diffusion-weighted MRI images acquired at b-value greater than 1000 s mm(-2) measure the diffusion of a restricted pool of water molecules. High b-value images are accompanied by a reduction in signal-to-noise ratio (SNR) due to the application of large diffusion gradients. By fitting the diffusion tensor model to data acquired at incremental b-value intervals, we determined the effect of SNR on tensor parameters in normal human brains, in vivo. In addition, we also investigated the impact of field strength on the diffusion tensor model. Data were acquired at 1.5 and 3T, at b-values 0, 1000, 2000 and 3000 s mm(-2) in twenty diffusion-sensitised directions. Fractional anisotropy (FA), mean diffusivity (MD) and principal eigenvector coherence (κ) were calculated from diffusion tensors fitted between datasets with b-values 0-1000, 0-2000, 0-3000, 1000-2000 and 2000-3000 s mm(-2). Field strength and b-value effects on diffusion parameters were analysed in white and grey matter regions of interest. Decreases in FA, κ and MD were found with increasing b-value in white matter. Univariate analysis showed a significant increase in FA with increasing field strength in highly organised white matter. These results suggest there are significant differences in diffusion parameters at 1.5 and 3T and that the optimal results, in terms of the highest values of FA in white matter, are obtained at 3T with a maximum b=1000 s mm(-2).
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Algoritmos
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Encéfalo
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Reconocimiento de Normas Patrones Automatizadas
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Interpretación de Imagen Asistida por Computador
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Aumento de la Imagen
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Imagen de Difusión por Resonancia Magnética
Tipo de estudio:
Diagnostic_studies
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Prognostic_studies
Límite:
Adult
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Female
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Humans
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Male
Idioma:
En
Revista:
Magn Reson Imaging
Año:
2013
Tipo del documento:
Article
País de afiliación:
Reino Unido