Hi Doug,

I am using the registration for subjects with ECoG electrodes. I have the electrode locations in RAS coordinates. I convert the RAS coordinates to talairach coordinates using the mri.nii and talairach.xfm files. I realize that talairach coordinates has some limitations, but I am just looking for ballpark estimates of the electrode locations (gyrus, broadman area). In this context do you think the registration is good enough? 

Sujith


On Thu, Dec 19, 2013 at 11:19 AM, Douglas N Greve <greve@nmr.mgh.harvard.edu> wrote:

It kind of depends on what is going to happen next. The talairach
transform is only used in a couple of contexts: to compute the estimated
intracranial volume and when doing volume-based analysis of subcortical
structures in FS-FAST. It would also be used if you report tal
coordinates for the individual (unlikely) or if you create a group
average subject (also unlikely). If none of those apply to you, then I
would leave it the way it is. If those do apply, then I would improve it.

doug

On 12/19/2013 10:58 AM, sujith vijayan wrote:
> Hi Bruce,
>
> Thanks! I looked at the other slices and they look similar to the
> screenshot I sent you; to my untrained eyes they look like they could
> use a slight rotation and shift. I am assuming that means it is a
> reasonable registration.
>
> However, I am not sure how much a talairach registration needs to be
> "off" before I need to fix it. The examples at
> https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/Talairach_freeview clearly
> need fixing. Are there any examples somewhere that show more marginal
> cases?
>
>
> Sujith
>
>
>
> On Wed, Dec 18, 2013 at 10:21 PM, Bruce Fischl
> <fischl@nmr.mgh.harvard.edu <mailto:fischl@nmr.mgh.harvard.edu>> wrote:
>
>     It looks reasonable to me, although you can't tell for sure from
>     just one slice
>     Bruce
>
>     On Dec 18, 2013, at 5:38 PM, sujith vijayan <svijayan9@gmail.com
>     <mailto:svijayan9@gmail.com>> wrote:
>
>>     Hi All,
>>
>>     I am wondering whether the talairach registration for one of my
>>     subjects needs to be fixed. It looks a little off to me, but I am
>>     not sure from reading the instructions on
>>     https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/Talairach_freeview
>>     whether the degree of difference I am seeing is to be expected or
>>     not. I've attached a screen shot.
>>
>>     Thanks,
>>     Sujith
>>
>>
>>       <Screen Shot 2013-12-18 at 5.31.00 PM.png>
>>
>>     _______________________________________________
>>     Freesurfer mailing list
>>     Freesurfer@nmr.mgh.harvard.edu
>>     <mailto:Freesurfer@nmr.mgh.harvard.edu>
>>     https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
>
>     The information in this e-mail is intended only for the person to
>     whom it is
>     addressed. If you believe this e-mail was sent to you in error and
>     the e-mail
>     contains patient information, please contact the Partners
>     Compliance HelpLine at
>     http://www.partners.org/complianceline . If the e-mail was sent to
>     you in error
>     but does not contain patient information, please contact the
>     sender and properly
>     dispose of the e-mail.
>
>
>
>
> _______________________________________________
> Freesurfer mailing list
> Freesurfer@nmr.mgh.harvard.edu
> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer

--
Douglas N. Greve, Ph.D.
MGH-NMR Center
greve@nmr.mgh.harvard.edu
Phone Number: 617-724-2358
Fax: 617-726-7422

Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting
FileDrop: https://gate.nmr.mgh.harvard.edu/filedrop2
www.nmr.mgh.harvard.edu/facility/filedrop/index.html
Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/

_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer