Hi Steve,
Thanks for your reply,
In your opinion the spatial resolution of the data can be considered as a covariable in the general linear model?
For example, one additional column (EV) to include the volume of the voxel.
Best regards,
Erick J. Canales-Rodríguez
(+34) 93 652 99 99 ext. 255
Unitat de Recerca, Benito Menni CASM (http://www.hospitalbenitomenni.org/Default.aspx)
Sant Boi del Llobregat (Barcelona), Espanya/España/Spain
Benito Menni Complex assistencial en Salut Mental
________________________________________
De: FSL - FMRIB's Software Library [[log in to unmask]] En nombre de Steve Smith [[log in to unmask]]
Enviado el: martes, 23 de diciembre de 2008 14:02
Para: [log in to unmask]
Asunto: Re: [FSL] TBSS with different diffusion data?
Hi,
See previous posts on this: in general people are very wary of trying
to combine data across different protocols. You will have a bias in
pretty much all diffusion-derived measures, which may not be trivally
modellable, and is almost certainly not solvable by re-interpolating
your data, sadly. However, IF you put in the protocol labelling as a
confound regressor to randomise, and IF your regressors of interest do
not correlate strongly with this, and IF your data is well matched
across the protocol groups, then you might get away with this........
Cheers.
On 23 Dec 2008, at 10:33, Erick Canales Rodriguez (Benito Menni CASM)
wrote:
> Hello FSL,
>
> My interest is to compare two groups of subjects with TBSS, however,
> the diffusion MRI data corresponding to each group was recorded with
> a different spatial resolution (in the same MRI machine). That is,
> the same b-value and diffusion gradient directions but different
> voxel size, the first group: 1.13x1.13x5 mm and the second one:
> 0.94x0.94x5 mm.
> My question is, it is possible to use TBSS to infer FA differences
> in groups with data at different spatial resolutions? Typically this
> procedure is not a good practice, however, I consider this
> possibility due to the data was measured with a resolution lower
> than the resolution of the template used in TBSS: 1x1x1 mm.
> A possible solution may be to interpolate the resulting FA images to
> the same spatial resolution prior to the TBSS analysis. A second
> variant may be to perform the interpolation directly on the measured
> diffusion data. There is any script in FSL to perform accurately
> these interpolations?
> Many thanks in advance,
>
> Erick J. Canales-Rodríguez
>
> (+34) 93 652 99 99 ext. 255
>
> Unitat de Recerca, Benito Menni CASM (http://www.hospitalbenitomenni.org/Default.aspx
> )
> Sant Boi del Llobregat (Barcelona), Espanya/España/Spain
>
> Benito Menni Complex assistencial en Salut Mental
> ________________________________________
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