>Dear FreeSurfer Support team, > >Thank you for your quick response. > >Is it fair to present both g-w.pct (100*(w-g)/((w+g)/2)) and g-w.ratio >(g/w) as GWR? I have seen the pct calculation presented as GWR in an >abstract that cited Salat (2009) in its introduction text.
>Also, is it fair to say that decreases in in g-w.pct indicate less >definition between >the g/w matter boundary as a decrease in g-w.ratio would indicate? If I >want to make a statement about reduced definition between the g/w matter >boundary, what calculation would you suggest? > >Thank you very much for your clarifications on this. > >Best, Derek > > > > >________________________________________ >Derek Sayre Andrews, MSc >PhD Candidate > >The Sackler Institute for Translational Neurodevelopment >Department of Forensic and Neurodevelopmental Sciences >Institute of Psychiatry, Psychology & Neuroscience, King's College London > >Telephone: +44 (0)20 7848 5701 >Email: derek.andr...@kcl.ac.uk > > > > > >On 03/12/2015 17:26, "Douglas N Greve" <gr...@nmr.mgh.harvard.edu> wrote: > >>g-w.pct is computed as >> >>pct = 100*(w-g)/((w+g)/2) >> >>in the pctsurfcon script >> >> >>On 12/03/2015 12:18 PM, Andrews, Derek wrote: >>> Dear FreeSurfer Support team and Community >>> >>> I am wondering if someone can give me an explanation of the difference >>> between g-w.pct and g:w ratio (as calculated by; fscalc lh.gm.mgh div >>> lh.wm.mgh -o lh.ratio.mgh) >>> Will both these measures essentially measure the relationship between >>> grey and white matter signal intensity but in a different way? >>> >>> >>> Best, Derek >>> >>> >>> >>>------------------------------------------------------------------------ >>> >>> *Derek Sayre Andrews, MSc* >>> PhD Candidate >>> >>> The Sackler Institute for Translational Neurodevelopment >>> >>> Department of Forensic and Neurodevelopmental Sciences >>> >>> Institute of Psychiatry, Psychology & Neuroscience, King's College >>>London >>> >>> Telephone: +44 (0)20 7848 5701 >>> Email: derek.andr...@kcl.ac.uk >>> >>> >>> >>> >>> _______________________________________________ >>> 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 >>gr...@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 >> >> >>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
