Dear Dianne
Just use your favourite GLM program and the method described in
Mumford et al. NeuroImage 2006.
Best
Torben
Torben Ellegaard Lund
Assistant Professor, PhD
The Danish National Research Foundation's Center of Functionally
Integrative Neuroscience (CFIN)
Aarhus University
Aarhus University Hospital
Building 30
Noerrebrogade
8000 Aarhus C
Denmark
Phone: +4589494380
Fax: +4589494400
http://www.cfin.au.dk
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@article{Mumford:2006eq,
Author = {Mumford, Jeanette A and Hernandez-Garcia, Luis and Lee,
Gregory R and Nichols, Thomas E},
Journal = {Neuroimage},
Number = {1},
Pages = {103--114},
Title = {Estimation efficiency and statistical power in arterial spin
labeling fMRI.},
Volume = {33},
Year = {2006 Oct 15},
Abstract = {Arterial spin labeling (ASL) data are typically
differenced, sometimes after interpolation, as part of preprocessing
before statistical analysis in fMRI. While this process can reduce the
number of time points by half, it simplifies the subsequent signal and
noise models (i.e., smoothed box-car predictors and white noise). In
this paper, we argue that ASL data are best viewed in the same data
analytic framework as BOLD fMRI data, in that all scans are modeled
and colored noise is accommodated. The data are not differenced, but
the control/label effect is implicitly built into the model. While the
models using differenced data may seem easier to implement, we show
that differencing models fit with ordinary least squares either
produce biased estimates of the standard errors or suffer from a loss
in efficiency. The main disadvantage to our approach is that non-white
noise must be modeled in order to yield accurate standard errors,
however, this is a standard problem that has been solved for BOLD
data, and the very same software can be used to account for such
autocorrelated noise.}}
Den 29/08/2008 kl. 20.03 skrev Dianne Patterson:
> Can anyone out there recommend software for analyzing perfusion mri?
>
> Thanks,
>
> Dianne
>
> --
> Dianne Patterson, Ph.D.
> [log in to unmask]
> University of Arizona
> SHLS 328
> 621-5105
|