On the effects of a varied diffusion time in vivo: is the diffusion in white matter restricted?
Nilsson, Markus LU ; Lätt, Jimmy LU ; Nordh, Emil LU ; Wirestam, Ronnie LU
; Ståhlberg, Freddy
LU
and Brockstedt, Sara
LU
(2009)
In Magnetic Resonance Imaging
27(2008 Jul 25).
p.176-187
- Abstract
- The aim of this work was to study the diffusion-related signal attenuation curves (signal-vs.-b curves) measured perpendicular and parallel to the neuronal fibers of the corticospinal tract in vivo and to determine whether effects of restricted diffusion could be observed when varying the diffusion time (T(D)). A biexponential model and a two-compartment model including exchange according to the Kärger formalism were employed to analyze the signal-vs.-b curves. To validate the two-compartment model, restricted diffusion with exchange was simulated for uniformly sized cylinders, using different diameters and exchange times. The model was shown to retrieve the simulated parameters well, also when the short gradient pulse approximation was... (More)
- The aim of this work was to study the diffusion-related signal attenuation curves (signal-vs.-b curves) measured perpendicular and parallel to the neuronal fibers of the corticospinal tract in vivo and to determine whether effects of restricted diffusion could be observed when varying the diffusion time (T(D)). A biexponential model and a two-compartment model including exchange according to the Kärger formalism were employed to analyze the signal-vs.-b curves. To validate the two-compartment model, restricted diffusion with exchange was simulated for uniformly sized cylinders, using different diameters and exchange times. The model was shown to retrieve the simulated parameters well, also when the short gradient pulse approximation was not met. The in vivo measurements performed perpendicular to the tracts, using b values up to 28000 s/mm(2) and T(D) values between 64 and 256 ms, did not show the effects of restricted diffusion as expected from previous ex vivo studies. The applied two-compartment model yielded an average axonal diameter of about 4 mum and an intracellular exchange time of about 300 ms, but did not fit statistically well to the data. In conclusion, this study indicates that if the diffusion is modeled as two compartments, of which one is restricted, exchange must be included in the model. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1180819
- author
- Nilsson, Markus
LU
; Lätt, Jimmy
LU
; Nordh, Emil
LU
; Wirestam, Ronnie
LU
; Ståhlberg, Freddy
LU
and Brockstedt, Sara
LU
- organization
- publishing date
- 2009
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Magnetic Resonance Imaging
- volume
- 27
- issue
- 2008 Jul 25
- pages
- 176 - 187
- publisher
- Elsevier
- external identifiers
-
- wos:000263533300004
- pmid:18657924
- scopus:59249099382
- pmid:18657924
- ISSN
- 1873-5894
- DOI
- 10.1016/j.mri.2008.06.003
- language
- English
- LU publication?
- yes
- id
- df1e7770-9487-4f9d-b38c-05ba4dd266ed (old id 1180819)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/18657924?dopt=Abstract
- date added to LUP
- 2016-04-04 07:40:19
- date last changed
- 2022-04-23 08:29:12
@article{df1e7770-9487-4f9d-b38c-05ba4dd266ed,
abstract = {{The aim of this work was to study the diffusion-related signal attenuation curves (signal-vs.-b curves) measured perpendicular and parallel to the neuronal fibers of the corticospinal tract in vivo and to determine whether effects of restricted diffusion could be observed when varying the diffusion time (T(D)). A biexponential model and a two-compartment model including exchange according to the Kärger formalism were employed to analyze the signal-vs.-b curves. To validate the two-compartment model, restricted diffusion with exchange was simulated for uniformly sized cylinders, using different diameters and exchange times. The model was shown to retrieve the simulated parameters well, also when the short gradient pulse approximation was not met. The in vivo measurements performed perpendicular to the tracts, using b values up to 28000 s/mm(2) and T(D) values between 64 and 256 ms, did not show the effects of restricted diffusion as expected from previous ex vivo studies. The applied two-compartment model yielded an average axonal diameter of about 4 mum and an intracellular exchange time of about 300 ms, but did not fit statistically well to the data. In conclusion, this study indicates that if the diffusion is modeled as two compartments, of which one is restricted, exchange must be included in the model.}},
author = {{Nilsson, Markus and Lätt, Jimmy and Nordh, Emil and Wirestam, Ronnie and Ståhlberg, Freddy and Brockstedt, Sara}},
issn = {{1873-5894}},
language = {{eng}},
number = {{2008 Jul 25}},
pages = {{176--187}},
publisher = {{Elsevier}},
series = {{Magnetic Resonance Imaging}},
title = {{On the effects of a varied diffusion time in vivo: is the diffusion in white matter restricted?}},
url = {{http://dx.doi.org/10.1016/j.mri.2008.06.003}},
doi = {{10.1016/j.mri.2008.06.003}},
volume = {{27}},
year = {{2009}},
}