Re: [HCP-Users] fMRISurface volume to surface mapping

[Timothy Coalson]

This is a little tricky, as v1.2.3's wb_command -metric-to-volume-mapping
does not reduce the mapped values by their partial voxel volumes.  The
dev_latest build available here should do this reduction by default (with
an option for the old behavior):

http://brainvis.wustl.edu/workbench/

With this version, you can map a metric file of all 1's to the volume with
the ribbon mapping method, and the results will be the estimated cortical
partial volume of each voxel.

Note that we do not recommend routine use of a dev_latest version,
particularly for wb_view, as we may change new features before the release,
resulting in undesirable interaction between a dev_latest and an official
release (palette names may change, resulting in resetting to default
palettes, scenes saved from dev_latest may give errors in release versions,
etc).

If you want more detail about the per-vertex mapping, then even in v1.2.3,
the -volume-to-surface-mapping command has an -output-weights-text
suboption to the -ribbon-constrained option, which dumps the voxel weights
used for mapping to a text format.  The order of fields is vertex number,
then groups of 4 representing voxel ijk indices and the weight for that
voxel.  These are simply used in a weighted average.

Tim


On Wed, Mar 28, 2018 at 10:59 AM, Thomas Kirk 
wrote:

> Dear all,
>
> I am writing to ask about the “novel partial volume weighted ribbon
> constrained volume to surface mapping algorithm” mentioned in the Glasser
> 2013 paper (p120, fMRISurface section).
>
> I am currently working on a similar tool to estimate partial volumes
> within the voxels of the cortical surface and I would like to compare my
> method to this part of the pipeline. As I am not interested in applying
> partial volume correction at this stage I need to extract just the partial
> volume estimates from the pipeline, ie, pre-correction. Does anyone know
> how I could go about this?
>
> Thank you in anticipation
> Tom Kirk
>
> Institute of Biomedical Engineering,
> University of Oxford, UK
>
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> HCP-Users mailing list
> HCP-Users@humanconnectome.org
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>

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[HCP-Users] fMRISurface volume to surface mapping

[Thomas Kirk]

Dear all, 

I am writing to ask about the “novel partial volume weighted ribbon constrained 
volume to surface mapping algorithm” mentioned in the Glasser 2013 paper (p120, 
fMRISurface section).

I am currently working on a similar tool to estimate partial volumes within the 
voxels of the cortical surface and I would like to compare my method to this 
part of the pipeline. As I am not interested in applying partial volume 
correction at this stage I need to extract just the partial volume estimates 
from the pipeline, ie, pre-correction. Does anyone know how I could go about 
this?

Thank you in anticipation 
Tom Kirk

Institute of Biomedical Engineering, 
University of Oxford, UK

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