Triple diffusion encoding MRI predicts intra-axonal and extra-axonal diffusion tensors in white matter.
Magn Reson Med
; 83(6): 2209-2220, 2020 06.
Article
en En
| MEDLINE
| ID: mdl-31763730
ABSTRACT
PURPOSE:
To demonstrate how triple diffusion encoding (TDE) MRI can be applied to separately estimate the intra-axonal and extra-axonal diffusion tensors in white matter (WM).METHODS:
Using a TDE pulse sequence with an axially symmetric b-matrix, diffusion MRI data were acquired at 3T for 3 healthy adults with an axial b-value of 4000 s/mm2 , a radial b-value of 307 s/mm2 , and 64 diffusion encoding directions. This acquisition was then repeated with the radial b-value set to 0. A previously proposed theory was applied to these data in order to estimate the intra-axonal diffusivity and axonal water fraction for each WM voxel. Conventional single diffusion encoding data were also obtained with b-values of 1000 and 2000 s/mm2 , which provided additional information sufficient for determining both the intra-axonal and extra-axonal diffusion tensors.RESULTS:
From the TDE data, the average intra-axonal diffusivity in WM was found to be 2.24 ± 0.18 µm2 /ms, and the average axonal water fraction was found to be 0.60 ± 0.11. From the 2 diffusion tensors, average WM values were estimated for several compartment-specific diffusion parameters. In particular, the extra-axonal mean diffusivity was 1.09 ± 0.19 µm2 /ms, the intra-axonal fractional anisotropy was 0.50 ± 0.14, and the extra-axonal fractional anisotropy was 0.23 ± 0.13.CONCLUSION:
By using a simple TDE pulse sequence with an axially symmetric b-matrix, the diffusion tensors for the intra-axonal and extra-axonal spaces can be separately estimated in adult WM. This allows one to determine compartment-specific diffusion properties for these 2 water pools.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Sustancia Blanca
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Límite:
Adult
/
Humans
Idioma:
En
Revista:
Magn Reson Med
Asunto de la revista:
DIAGNOSTICO POR IMAGEM
Año:
2020
Tipo del documento:
Article