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Investigation of spatial resolution, partial volume effects and smoothing in functional MRI using artificial 3D time series.

Weibull, Andreas LU ; Gustafsson, Helen LU ; Mattsson, Sören LU and Svensson, Jonas LU (2008) In NeuroImage 41(2). p.346-353
Abstract
This work addresses the balance between temporal signal-to-noise ratio (tSNR) and partial volume effects (PVE) in functional magnetic resonance imaging (fMRI) and investigates the impact of the choice of spatial resolution and smoothing. In fMRI, since physiological time courses are monitored, tSNR is of greater importance than image SNR. Improving SNR by an increase in voxel volume may be of negligible benefit when physiological fluctuations dominate the noise. Furthermore, at large voxel volumes, PVE are more pronounced, leading to an overall loss in performance. Artificial fMRI time series, based on high-resolution anatomical data, were used to simulate BOLD activation in a controlled manner. The performance was subsequently quantified... (More)
This work addresses the balance between temporal signal-to-noise ratio (tSNR) and partial volume effects (PVE) in functional magnetic resonance imaging (fMRI) and investigates the impact of the choice of spatial resolution and smoothing. In fMRI, since physiological time courses are monitored, tSNR is of greater importance than image SNR. Improving SNR by an increase in voxel volume may be of negligible benefit when physiological fluctuations dominate the noise. Furthermore, at large voxel volumes, PVE are more pronounced, leading to an overall loss in performance. Artificial fMRI time series, based on high-resolution anatomical data, were used to simulate BOLD activation in a controlled manner. The performance was subsequently quantified as a measure of how well the resulted activation matched the simulated activation. The performance was highly dependent on the spatial resolution. At high contrast-to-noise ratio (CNR), the optimal voxel volume was small, i.e. in the region of 2(3) mm(3). It was also shown that using a substantially larger voxel volume in this case could potentially negate the CNR benefits. The optimal smoothing kernel width was dependent on the CNR, being larger at poor CNR. At CNR >1, little or no smoothing proved advantageous. The use of artificial time series gave an opportunity to quantitatively investigate the effects of partial volume and smoothing in single subject fMRI. It was shown that a proper choice of spatial resolution and smoothing kernel width is important for fMRI performance. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
NeuroImage
volume
41
issue
2
pages
346 - 353
publisher
Elsevier
external identifiers
  • wos:000256271100017
  • pmid:18400520
  • scopus:44149126416
ISSN
1095-9572
DOI
10.1016/j.neuroimage.2008.02.015
language
English
LU publication?
yes
id
ff1655aa-a439-4739-b817-96df7d502e81 (old id 1147570)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/18400520?dopt=Abstract
date added to LUP
2008-05-07 13:30:23
date last changed
2017-09-10 03:36:22
@article{ff1655aa-a439-4739-b817-96df7d502e81,
  abstract     = {This work addresses the balance between temporal signal-to-noise ratio (tSNR) and partial volume effects (PVE) in functional magnetic resonance imaging (fMRI) and investigates the impact of the choice of spatial resolution and smoothing. In fMRI, since physiological time courses are monitored, tSNR is of greater importance than image SNR. Improving SNR by an increase in voxel volume may be of negligible benefit when physiological fluctuations dominate the noise. Furthermore, at large voxel volumes, PVE are more pronounced, leading to an overall loss in performance. Artificial fMRI time series, based on high-resolution anatomical data, were used to simulate BOLD activation in a controlled manner. The performance was subsequently quantified as a measure of how well the resulted activation matched the simulated activation. The performance was highly dependent on the spatial resolution. At high contrast-to-noise ratio (CNR), the optimal voxel volume was small, i.e. in the region of 2(3) mm(3). It was also shown that using a substantially larger voxel volume in this case could potentially negate the CNR benefits. The optimal smoothing kernel width was dependent on the CNR, being larger at poor CNR. At CNR >1, little or no smoothing proved advantageous. The use of artificial time series gave an opportunity to quantitatively investigate the effects of partial volume and smoothing in single subject fMRI. It was shown that a proper choice of spatial resolution and smoothing kernel width is important for fMRI performance.},
  author       = {Weibull, Andreas and Gustafsson, Helen and Mattsson, Sören and Svensson, Jonas},
  issn         = {1095-9572},
  language     = {eng},
  number       = {2},
  pages        = {346--353},
  publisher    = {Elsevier},
  series       = {NeuroImage},
  title        = {Investigation of spatial resolution, partial volume effects and smoothing in functional MRI using artificial 3D time series.},
  url          = {http://dx.doi.org/10.1016/j.neuroimage.2008.02.015},
  volume       = {41},
  year         = {2008},
}