[MINC-users] 6-parameter fitting with minctracc

[Vladimir Fonov]

Hello,

I also suggest using nonlinear registration ( 8mm step size should be
enough) or at least lsq12 when averaging scans acquired during
different scanning sessions. Also, do you normalize intensities
between scans ?


On Sat, Feb 20, 2010 at 12:56 PM, Jason Lerch <jason at bic.mni.mcgill.ca> wrote:
> In my limited experience you're much better off processing each of the scans independently and then either averaging the thickness maps at the end or, even better, using mixed effects models and all your data for the analysis.
>
> Alternately, if you really want to go the higher SNR route, I have a nonlinear-mritoself perl script that might help.

> On 2010-02-20, at 12:36 PM, EJ Nikelski wrote:
>>  I need some validation and/or suggestions (or both?).  I have
>> subject scans (T1) for which each subject was scanned multiple times
>> (same scanner), at difference points in time.  For each subject, some
>> of the scans were acquired within the same scanning sessions, some
>> were acquired within a 6-month window.
>>
>>     I would like to combine the scans to give me the best SNR for
>> Civet processing.  I've tried specifying one of the scans as the
>> "target" and then using "mritoself" to align all others to it; all
>> aligned scans and the "target" would then be mincaverage'd.  The
>> results are OK, but not splendid, as Civet spits up during tissue
>> classification on one of the averaged volumes, although the
>> non-averaged scans go through without error.  I'm using defaults for
>> the mritoself call, plus "-nocrop".




-- 
Best regards,
 Vladimir S. Fonov ~ v.s.fonov <@> ilmarin.info