Ok, thanks! ----- Ursprüngliche Mail ----- Von: "Bruce Fischl" <fis...@nmr.mgh.harvard.edu> An: "Freesurfer support list" <freesurfer@nmr.mgh.harvard.edu> Gesendet: Montag, 4. Juli 2016 15:37:57 Betreff: Re: [Freesurfer] controlling for total gray matter volume
sounds right to me Bruce On Mon, 4 Jul 2016, Clara Kühn wrote: > I have decided now to not control for ICV or total gray matter volume when > looking at cotrical thickness but to control for total gray matter volume > when looking at surface area. Does that sound about right? > > Cheers, Clara > > ----- Ursprüngliche Mail ----- > Von: "Arkadiy Maksimovskiy" <arkad...@bu.edu> > An: freesurfer@nmr.mgh.harvard.edu > Gesendet: Samstag, 2. Juli 2016 18:36:51 > Betreff: Re: [Freesurfer] controlling for total gray matter volume > > Hi Clara, > > If I am understanding your question correctly, you don't need to control for > brain volume when looking at thickness analyses. > > See quote below from this link: > > http://www.freesurfer.net/fswiki/eTIV > > "Note that this correction is only useful in situations where the structure > scales with head size. Outside of this, correction just adds noise, or > provides inaccurate data. In the case of the measures from Freesurfer, one > would apply correction to the volume measures and not thickness measures. > This is because volume scales with head size which is mostly due to changes > in surface area, whereas thickness alone scales to a much less degree." > > Best, > Arkadiy > > On Sat, Jul 2, 2016 at 12:00 PM, < freesurfer-requ...@nmr.mgh.harvard.edu > > wrote: > > > Send Freesurfer mailing list submissions to > freesurfer@nmr.mgh.harvard.edu > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > or, via email, send a message with subject or body 'help' to > freesurfer-requ...@nmr.mgh.harvard.edu > > You can reach the person managing the list at > freesurfer-ow...@nmr.mgh.harvard.edu > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Freesurfer digest..." > > > Today's Topics: > > 1. controlling for total gray matter volume (Clara K?hn) > 2. cotrolling for total gray matter volume (Clara K?hn) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 30 Jun 2016 15:19:43 +0200 (CEST) > From: Clara K?hn < cku...@cbs.mpg.de > > Subject: [Freesurfer] controlling for total gray matter volume > To: Freesurfer support list < freesurfer@nmr.mgh.harvard.edu > > Message-ID: > < 600644700.119350.1467292783757.javamail.zim...@cbs.mpg.de > > Content-Type: text/plain; charset=utf-8 > > Dear FreeSurfer experts, > > I would like to look at longitudinal thickness data and want to control for > total gray matter volume. Should I use that information from the CROSS before > anything has been registered and smoothed or from the LONG after they have > been registered to the BASE? > Also I was wondering if it is useful to control for total gray matter volume > when looking at surface area? > > Thanks for your help! > Clara > > > ------------------------------ > > Message: 2 > Date: Thu, 30 Jun 2016 15:01:06 +0200 (CEST) > From: Clara K?hn < cku...@cbs.mpg.de > > Subject: [Freesurfer] cotrolling for total gray matter volume > To: Freesurfer support list < freesurfer@nmr.mgh.harvard.edu > > Message-ID: > < 1473114832.117985.1467291666701.javamail.zim...@cbs.mpg.de > > Content-Type: text/plain; charset=utf-8 > > Dear FreeSurfer experts, > > I would like to look at longitudinal thickness data and want to control for > total gray matter volume. Should I use that information from the CROSS before > anything has been registered and smoothed or from the LONG after they have > been registered to the BASE? > Also I was wondering if it is useful to control for total gray matter volume > when looking at surface area? > > Thanks for your help! > Clara > > _______________________________________________ Freesurfer mailing list 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
