Linked Life Data

18002728

Source:http://linkedlifedata.com/resource/pubmed/id/18002728

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2007-11-16
pubmed:abstractText
In region of interest (ROI) based functional magnetic resonance imaging (fMRI) group analysis, errors in delineation of an ROI or inclusion of non-active voxels within an ROI can bias the statistical results. Addressing these concerns, this paper presents a new fMRI processing method that simultaneously refines ROI delineation and spatially denoises fMRI activation statistics within the ROI. The underlying assumption is that activation statistics within a small neighborhood are spatially correlated, thereby exhibit similar levels of influence on the overall ROI's response. Based on this assumption, we first identify outlier voxels as those having undue influence on an ROI's feature. Isolated outlier voxels at region boundaries are then removed, thereby refining the ROI delineation. The remaining outlier voxels are de-weighted based on their influence relative to their neighbors to reduce the effects of voxels deemed falsely active in later analysis. The proposed method was tested on real fMRI data collected from 8 healthy subjects performing a bulb-squeezing motor task at various frequencies. Using the proposed method, enhanced capability for detection of frequency-related activation map feature differences (AMFD) was demonstrated when compared to Gaussian spatial smoothing of ROI activation statistics. The validity of the proposed method is suggested by the fact that using one feature for denoising (e.g. spatial variance) results in greater effect size in another feature (e.g. average activation statistics magnitude). Our results demonstrate the importance of accurate ROI delineation in ROI-based fMRI analysis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
1557-170X
pubmed:author
pubmed:issnType
Print
pubmed:volume
2007
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3404-7
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Joint spatial denoising and active region of interest delineation in functional magnetic resonance imaging.
pubmed:affiliation
Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 Canada. bernardn@ece.ubc.ca
pubmed:publicationType
Journal Article, Evaluation Studies