Dear Zheng,
You can build a GLM with a single group, and then look at the residuals. Or, even easier: just divide the volumes of each subject by his/her ICV (the answers won’t be identical, but should definitely be quite similar).
Cheers,
/Eugenio
--
Juan Eugenio Iglesias
ERC Senior Research Fellow
Translational Imaging Group
University College London
http://www.jeiglesias.com
http://cmictig.cs.ucl.ac.uk/
From: <freesurfer-bounces@nmr.mgh.harvard.edu> on behalf of
郑凤莲 <13181786167@163.com>
Reply-To: Freesurfer support list <freesurfer@nmr.mgh.harvard.edu>
Date: Friday, 1 December 2017 at 12:55
To: Freesurfer support list <freesurfer@nmr.mgh.harvard.edu>
Subject: Re: [Freesurfer] hippocampus subfields
Hi Bruce,
I am sorry for asking you question as this, but I really don't know how to do it?
It seems that GLM is suitable for there are two groups or more. But I only have one group, If I want to get the line trend with eTIV corrected for the relationship
between age and volume, what should I do?
The picture is my result, but it doesn't corrected by eTIV. I appreciate your help, please.
Thanks a lot!
Zheng
At 2017-11-22 10:29:43, "Bruce Fischl" <fischl@nmr.mgh.harvard.edu> wrote:>you would include it as a nuisance variable in the glm
>On Wed, 22 Nov 2017,
>郑凤莲 wrote:
>
>> Hi Bruce,
>>
>> Thanks for your quick reply. These results are not correted by eTIV, If eTIV are corrected, I
>> can only get the p value and scatter plot, I can't get the line trend. Do you know how to get the
>> line trend with eTIV corrected as these results?
>>
>> Thanks,
>> Zheng
>>
>>
>>
>>
>>
>> 在 2017-11-22 10:14:16，"Bruce Fischl" <fischl@nmr.mgh.harvard.edu> 写道：
>> >is this eTIV corrected? I would look at some of the outliers and make
>> >sure that the segmentations are accurate. Certainly the trend is in the
>> >correct (and depressing) direction.
>> >
>> >cheers
>> >Bruce
>> >On Wed, 22 Nov 2017, 郑凤莲 wrote:
>> >
>> >> Hi Bruce,
>> >>
>> >> Thanks for your advice. There are a part of the result. Blue color stands women, and Red colo
>> r
>> >> stands men.
>> >> The number of the data is not enough large. Are they ok? May I use them in my paper?
>> >> [IMAGE][IMAGE][IMAGE]
>> >>
>> >>
>> >> Thanks a lot !
>> >> Zheng
>> >>
>> >>
>> >>
>> >>
>> >> At 2017-11-20 10:15:49, "Bruce Fischl" <fischl@nmr.mgh.harvard.edu> wrote:
>> >> >Hi Zheng
>> >> >
>> >> >I would scatter plot age vs. volume, coloring men and women differently
>> >> >(or different symbols) with and without eTIV correction to get an idea of
>> >> >what is going on
>> >> >
>> >> >cheers
>> >> >Bruce
>> >> >
>> >> >
>> >> >On Mon, 20 Nov
>> >> >2017, 郑凤莲 wrote:
>> >> >
>> >> >> Hi Bruce,
>> >> >>
>> >> >> My data is loss from 35 to 40. But the uniform of sex is not well from 40 to 55 and from 56
>> to
>> >> >> 71. I did the correlation analysis between age and volume. I don't know how I can explain this
>> >> >> problem.
>> >> >> Thanks again.
>> >> >>
>> >> >> Sincerely,
>> >> >> Zheng
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> >> >> At 2017-11-20 09:35:45, "Bruce Fischl" <fischl@nmr.mgh.harvard.edu> wrote:
>> >> >> >Hi Zheng
>> >> >> >
>> >> >> >how uniform is your distribution? I'm hardly an expert on this, but I
>> >> >> >wouldn't expect very large effects until you get into the older end of
>> >> >> >that range. Have you scatter plotted your data?
>> >> >> >Bruce
>> >> >> >On Mon, 20 Nov 2017, 郑凤莲
>> >> >> >wrote:
>> >> >> >
>> >> >> >>
>> >> >> >> Hi Bruce,
>> >> >> >>
>> >> >> >> Thank you for your help.
>> >> >> >> I have 54 subjects, aged from 21 to 71 and only one group. I want to compare the chang
>> e o
>> >> f
>> >> >> >> hippocampus volume with age. The results before and after doing the correction for eTIV are
>> th
>> >> e
>> >> >> >> same. Where is wrong? Or if there is no error, how can I explain it in discussion?
>> >> >> >>
>> >> >> >> Thanks,
>> >> >> >> Zheng
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >> At 2017-11-20 04:55:49, "Bruce Fischl" <fischl@nmr.mgh.harvard.edu> wrote:
>> >> >> >> >Hi Zheng
>> >> >> >> >
>> >> >> >> >yes, I see. Maybe the effect is smaller than you have the power to see, or
>> >> >> >> >there is no effect? You would need to give us more details for us to help.
>> >> >> >> >Are you correcting for eTIV? What measure are you comparing?
>> >> >> >> >
>> >> >> >> >cheers
>> >> >> >> >Bruce
>> >> >> >> > On Sun, 19 Nov 2017, 郑凤莲 wrote:
>> >> >> >> >
>> >> >> >> >> Hi Bruce,
>> >> >> >> >>
>> >> >> >> >> I am sorry for this situation.
>> >> >> >> >> In the first way, there was an statistical difference in left hippocampus, but no d
>> iff
>> >> ere
>> >> >> nce
>> >> >> >> in
>> >> >> >> >> right hippocampus. In the second way, there was both no statistical difference in left o
>> r
>> >> >> >> >> right hippocampus. I don't know what causes this result.
>> >> >> >> >> Can you understand me this time?
>> >> >> >> >>
>> >> >> >> >> Thanks,
>> >> >> >> >> Zheng
>> >> >> >> >>
>> >> >> >> >>
>> >> >> >> >>
>> >> >> >> >>
>> >> >> >> >> At 2017-11-18 22:58:56, "Bruce Fischl" <fischl@nmr.mgh.harvard.edu> wrote:
>> >> >> >> >> >Hi Zheng
>> >> >> >> >> >
>> >> >> >> >> >no difference between what and what?
>> >> >> >> >> >
>> >> >> >> >> >cheers
>> >> >> >> >> >Bruce
>> >> >> >> >> >On Fri, 17 Nov 2017, 郑凤莲 wrote:
>> >> >> >> >> >
>> >> >> >> >> >> Hi professor,
>> >> >> >> >> >>
>> >> >> >> >> >> I am using Freesurfer for DTI data. When I run 'mri_segstats', I
>> >> >> >> >> >> got the result that there w
>> >> >> >> >> as
>> >> >> >> >> >> an obvious difference in left hippocampus, but no difference in right hippocampus. Th
>> en,
>> >> I
>> >> >> run
>> >> >> >> >> >> segmentation of hippocampus subfields. The result showed there is no difference in to
>> tal
>> >> le
>> >> >> ft
>> >> >> >> or
>> >> >> >> >> >> right hippocampus, and only in two right hippocampus subfields has significant differ
>> enc
>> >> e.
>> >> >> Why
>> >> >> >> is
>> >> >> >> >> >> there inconsistent result in two means?
>> >> >> >> >> >> Thank you very much.
>> >> >> >> >> >>
>> >> >> >> >> >> Sincerely,
>> >> >> >> >> >> Zheng
>> >> >> >> >> >>
>> >> >> >> >> >>
>> >> >> >> >> >>
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