Hello Adam, Michael,
just to follow this up, it is to be expected that an ever-improving
piece of software such as vbm8 gives different results with different
versions (else there weould be no sense in improving it :). If you want
to know what changed, there is a very meticuous chages.txt file in the
distribution. Irrespective of that, I think it is generally a really
good idea to use one software revision for the (final) analysis of all
subjects.
Cheers,
Marko
Adam Gorka wrote:
> Hello Michael,
>
> Our group has been collecting data for two years and we have been
> processing it as we go. We noticed the same thing. As we collected data
> across time, we updated our versions of vbm8. To make sure the new
> versions were the same as the old, we processed the same data with both
> versions. The different versions produced different Total Grey Matter
> /White Matter/ CSF volumes in the text file generated during
> preprocessing. Additionally, the grey matter segmented image produced
> was different for the old and new versions.
>
> I am unsure what is changed across the different versions that produces
> this difference. We chose to process all our data with the same version.
> Hope this helps.
>
> Adam
>
>
>
> On Fri, Jan 27, 2012 at 1:52 PM, Michael <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
> Hello,
>
> I've conducted some longitudinal vbm analysis back in spring 2011
> with version vbm8_r409. The results looked promising. However, after
> making the upgrade to vbm_r435, I noticed the same exact analysis i
> conducted on the same data set yielded different results. Just to
> check, I preprocessed the data set using version 409 and also using
> 435. So, i'm assuming there is a difference in the preprocessing
> calculations and this is due to the upgrade(s)? Has anybody else
> experienced this? Your help would greatly be appreciated.
>
> Thanks,
>
> Michael
>
>
--
____________________________________________________
PD Dr. med. Marko Wilke
Facharzt für Kinder- und Jugendmedizin
Leiter, Experimentelle Pädiatrische Neurobildgebung
Universitäts-Kinderklinik
Abt. III (Neuropädiatrie)
Marko Wilke, MD, PhD
Pediatrician
Head, Experimental Pediatric Neuroimaging
University Children's Hospital
Dept. III (Pediatric Neurology)
Hoppe-Seyler-Str. 1
D - 72076 Tübingen, Germany
Tel. +49 7071 29-83416
Fax +49 7071 29-5473
[log in to unmask]
http://www.medizin.uni-tuebingen.de/kinder/epn
____________________________________________________
|