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 change of
>> hippocampus volume with age. The results before and after doing the correction for eTIV are the
>> 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 difference
>>  in
>> >> right hippocampus. In the second way, there was both no statistical difference in left or
>> >> 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. Then, I run
>> >> >> segmentation of hippocampus subfields. The result showed there is no difference in total left 
>> or
>> >> >> right hippocampus, and only in two right hippocampus subfields has significant difference. Why
>>  is
>> >> >> there inconsistent result in two means? 
>> >> >>     Thank you very much.
>> >> >> 
>> >> >> Sincerely,
>> >> >> Zheng
>> >> >> 
>> >> >> 
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