In my honest opinion, all subjects need to be processed the same way.
If you have 2 scans, you could use the suggested approaches, or you
could coregister them, then average them in. After averaging , you can
do the rest of the processing.

Averaging should give similar as increasing the NEX.

On Thursday, May 19, 2011, Jonathan Peelle <[log in to unmask]> wrote:
> Dear Steven,
>>   We are comparing two groups of 13 subjects with DARTEL VBM8. I know this
>> is underpowered, but wondered if there is any way to use the multiple T1
>> images that were acquired for some of the subjects (in the same session). My
>> initial thought is to process all T1s and use the quality check to see if
>> there is a "better" image when I have two for a given subject. Are there
>> better ways to use multiple T1s?
> In the "new segment" option in SPM8, you can specify multiple
> modalities of images for segmentation.  I assume you could also
> provide SPM with 2 T1 images.  SPM will then use the combined
> information across images to assign tissue class probabilities, and in
> general I would think that more data would provide a more accurate
> result.  However, I think you'd want to process all of your subjects
> the same way.  So if you only have multiple T1s for a subset, I would
> probably stick with the approach you suggest—see if you can identify a
> "better" image.  (Or, if this is hard to determine, then just use the
> first.)  But if anyone else has alternate approaches, I'd be very
> interested to hear!
> Best regards,
> Jonathan


Best Regards, Donald McLaren
D.G. McLaren, Ph.D.
Postdoctoral Research Fellow, GRECC, Bedford VA
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Office: (773) 406-2464
This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED
intended only for the use of the individual or entity named above. If the
reader of the e-mail is not the intended recipient or the employee or agent
responsible for delivering it to the intended recipient, you are hereby
notified that you are in possession of confidential and privileged
information. Any unauthorized use, disclosure, copying or the taking of any
action in reliance on the contents of this information is strictly
prohibited and may be unlawful. If you have received this e-mail
unintentionally, please immediately notify the sender via telephone at (773)
406-2464 or email.