Hi, thank you I think this would test something different: 'how much a brain area is atrophic controlling for the average brain atrophy' and not 'how much a brain area is atrophic controlling for the individual differences in head size'. Doesn't it?
Angela "Harms, Michael" <mha...@wustl.edu> ha scritto: > Hi, > Why not use a measurement of brain size rather than “eTIV”? > > cheers, > -MH > > -- > Michael Harms, Ph.D. > > ----------------------------------------------------------- > Conte Center for the Neuroscience of Mental Disorders > Washington University School of Medicine > Department of Psychiatry, Box 8134 > 660 South Euclid Ave.Tel: 314-747-6173 > St. Louis, MO 63110Email: mha...@wustl.edu > > > > > On 2/21/16, 6:06 AM, "freesurfer-boun...@nmr.mgh.harvard.edu on behalf of > Angela Favaro" <freesurfer-boun...@nmr.mgh.harvard.edu on behalf of > angela.fav...@unipd.it> wrote: > > there is a mistake in the graph, hippocampal volume is TIV2 > I apologize for that! > > Angela Favaro <angela.fav...@unipd.it> ha scritto: > >> Hi Bruce, >> please find attached the graph of the correlation between the two time >> point. I did not find outliers or failures. However the discrepancy >> between TIVs is particularly high in few cases. Obviously these data >> are those before running longitudinal streaming >> This is a sample of adolescents with low body weight (anorexia nervosa). >> In my previous study (on young adults with low weight) I found no >> correlation between TIV and body weight and high correlations between >> fs estimated TIV and manually segmented TIV (r=0.94 in the whole >> sample and r=0.93 in the underweight sample (n=38)). >> Do you think that the young age can be a factor? or patients who are >> more acutely underweight? >> Thank you for any suggestion >> >> Angela >> >> >> Bruce Fischl <fis...@nmr.mgh.harvard.edu> ha scritto: >> >>> Hi Angel >>> >>> the time1/time2 correlation of eTIV is pretty worrisome. Are you sure >>> that there aren't outliers/failures in that set? >>> >>> Bruce >>> >>> >>> On Sun, 14 Feb 2016, angela.fav...@unipd.it wrote: >>> >>>> Dear Freesurfer experts, >>>> I have a question about eTIV (FS 5.3) which I use as a covariate where >>>> appropriate. Is it in some way influenced by the presence of brain >>>> atrophy? >>>> I have a new sample of subjects in a longitudinal study: at time 1 they >>>> have some atrophy (due to low body weight) that improves in time 2 (4 >>>> months). I observed that eTIV-time1 is slightly correlated with weight >>>> (r=0.3) whereas no correlation is present at time 2. The correlation >>>> between eTIV-time1 and eTIV-time2 is somewhat lower than expected >>>> (r=0.53) >>>> and is lower than correlation between SegBrain_Vol_1 and SegBrain_Vol_2 >>>> (0.65). >>>> >>>> Do you suggest in these cases to perform manual segmentation to obtain >>>> TIV? or is there any other method (in freesurfer) to obtain an >>>> estimate of >>>> TIV not influenced by brain atrophy? What about using BrainMask_to_TIV? >>>> >>>> Thank you for any suggestion >>>> >>>> Angela >>>> >>>> >>>> _______________________________________________ >>>> Freesurfer mailing list >>>> Freesurfer@nmr.mgh.harvard.edu >>>> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer >>>> >>>> >>>> >>> _______________________________________________ >>> 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 > > > ________________________________ > The materials in this message are private and may contain Protected > Healthcare Information or other information of a sensitive nature. > If you are not the intended recipient, be advised that any > unauthorized use, disclosure, copying or the taking of any action in > reliance on the contents of this information is strictly prohibited. > If you have received this email in error, please immediately notify > the sender via telephone or return mail. > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
