Thanks a lot for your response and your help. The reference number for
the upload is 622827.
I have included the 2 versions of the mask in example_func space,
obtained with the linear and non-linear registrations.
Stéphane Jacobs - Chercheur post-doctorant / Post-doctoral researcher
Espace et Action - Inserm U864
16 avenue du Doyen Lépine
69676 Bron Cedex, France
Téléphone / Phone: (+33) (0)4-72-91-34-38
Jesper Andersson a écrit :
> Dear Stephane,
>> I'm using Featquery to compute percent signal change from various
>> regions of
>> interest. I've first run Featquery with the default settings, which
>> were to
>> use the inverse of non-linear registration from highres2standard and the
>> inverse of the affine transformation from example_func2highres.
>> However, I
>> noticed that several subjects (I still need to check the others), the
>> resulting mask transformed from standard to native EPI space is
>> small, 2 or 3 voxels at best, sometimes empty, while the volume of
>> the mask
>> in standard space is 528 mm2 (66 voxels). I checked the
>> example_func2standard registration and it looks fine.
>> To compare, I manually registered the standard mask to EPI space
>> using only
>> the inverse of the affine transformations from example_func2highres and
>> highres2standard, using the default interpolation method and
>> post-interpolation threshold value. Now, I obtain a 72 voxel mask
>> (2812 mm2)
>> that is even bigger than the original one in standard space...
>> At this point I'm a bit confused as to why the mask obtained with linear
>> "back-registration" is so big (might need to adjust the
>> threshold?), but what I really don't get is why the results between
>> the 2
>> registration methods are so different.
>> Any hint as to what I might have done wrong would be greatly
> I must admit to being confused too. I have had a look at the scripts,
> and right now I don't have an idea so I would probably need to have a
> look at your data.
> Could you please tar up your
> example_func image file
> image file with mask in standard space
> highres2standard_warp image file
> highres2standard_warp_inv image file
> image file with mask after transformation into example_func space
> and then upload them to http://www.fmrib.ox.ac.uk/cgi-bin/upload.cgi
> and send me the reference number?