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.Andrews@kcl.ac.uk
On 03/12/2015 17:26, "Douglas N Greve" greve@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.Andrews@kcl.ac.uk
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Andrews, Derek