[Brains-users] Gyrification index

[Roberto Roiz Santiáñez]

thanks Grag


On Mie, 2 de Julio de 2008, 7:04 pm, Greg Harris dijo:
> Roberto,
>
> The short answer is no, brains2 doesn't produce a Gyrification Index.
>
> The best we can do in brains2 is a GTSurface workup.  After you create
> your
> left and right surfaces with the Workup > Run Surface ... panel as
> directed
> in the manual, you can Measure Surface Mask (b2 measure GTSurface mask)
> which will produce measures like
>
>    FundalSumArea 48339.711333774794184
>    FundalMeanCurvature -0.097746881788291
>    FundalStdDevCurvature 0.087318902788583
>    GyralSumArea 53227.931754728640954
>    GyralMeanCurvature 0.074606313229215
>    GyralStdDevCurvature 0.052893375664620
>    TotalSumArea 101567.643088503435138
>    FundalMeanDepth 1.741774498054365
>    GyralMeanDepth 1.884058467992384
>    TotalMeanDepth 1.816340385490125
>
> along with some others you should ignore.  Your mask will focus the
> surface
> measurement on a region of interest.  Curvatures of 0.0000 indicate flat,
> negative is concave, positive is convex.  Depths are the distance from
> surface vertices to white matter;  since the surface follows a path midway
> through the gray mantle, brains2 depth is an index.
>
> The GTSurface workup commands are not built under SunOS and MacOSX.  You
> will need to install brains2 on a Linux machine.
>
> On the other hand, a FreeSurfer workup will offer you these measures:
> MeanCurvature, GaussianCurvature, FoldingIndex, CurvatureIndex.  Both of
> these indices seem to be highly correlated with the sum of surface area
> for
> the region.
>
> The brains2 curvatures correspond to statistics of the MeanCurvatures,
> their means and standard deviations on the given mask region of interest.
>
> Greg Harris
>
>
> On 7/2/08 4:52 AM, "Roberto Roiz Santiáñez" <rroiz at humv.es> wrote:
>
>>
>>
>> Hello
>>
>> Does anyone know whether it is possible to calculate the Gyrification
>> Index with BRAINS2
>>
>> Regards
>
>
>
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-- 
Roberto Roiz Santiáñez
Laboratorio de Neuroimagen en Psiquiatría
Hospital Universitario Marqués de Valdecilla
Santander, España
Tel: +34 942202520 Ext: 73958
rroiz at humv.es