[MINC-users] cortical thickness normalization

[Morgan Hough]

Hi there,

I just wanted to see if anyone remembers the HBM abstract that Bruce is 
referring to here regarding cortical thickness normalization. Does 
anyone have a different opinion on this matter? Thanks in advance for 
your time.

Cheers,

-Morgan


  Re: [Freesurfer] cortical thickness normalization

Bruce Fischl
Mon, 07 Jan 2008 09:21:28 -0800

Hi Paul,


I think volume you can normalize with eTIV, but how to normalize 
thickness is an open question. You could argue it should be eTIV^(1/3), 
but I know at least one HBM abstract a couple of years ago from the MNI 
showing that you shouldn't normalize at all. If your effects are focal 
then normalizing by avg thickness is reasonable, or maybe the average of 
some region that you expect to be unaffected?

cheers,
Bruce



On Mon, 7 Jan 2008, Paul Greenberg wrote:

    Dear Freesurfers,

      

    When comparing cortical gray matter volumes between groups it is
    appropriate to normalize subject's mean cortical volume in each
    cortical parcellation by their eTIV. Is there a corresponding value
    appropriate for normalizing cortical thickness? Would mean cortical
    thickness for a single hemisphere be an appropriate normalization
    factor? We are interested in comparing cortical thickness between a
    control group and a group of people with a degenerative brain disease.

    Thanks very much,
    Paul



      

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

-- 

-----------------------------------------------------------------------
Morgan Hough, D. Phil. Student,  Oxford University FMRIB Centre

FMRIB, JR Hospital, Headington, Oxford  OX3 9DU, UK
+44 (0) 1865 222466  (fax 222717)
mhough at fmrib.ox.ac.uk  http://www.fmrib.ox.ac.uk/~mhough
-----------------------------------------------------------------------