The voxel sizes need to include the gaps so that lengths etc are
correct and rigid body rotations can be done properly.
Best regards,
-John
On 27 September 2010 10:24, Daniel Sodan <[log in to unmask]> wrote:
> Thank you John for the answer.
> Are the size of structures relates to anatomical images (segmentation etc)?
> I just miss how exactly in EPI fMRI images the gap helps me? For example, if
> my slice sickness 2.5 mm and I add 0.5 mm of gap, my voxel Z dimension
> becomes 3 mm. This means that all my data consists of voxles, which were
> scanned for 5/6 of its volume.
>
> On Mon, Sep 27, 2010 at 10:34 AM, John Ashburner <[log in to unmask]>
> wrote:
>>
>> Gaps between slices, along with slice thickness, are included within
>> the voxel dimensions. This allows the sizes of structures to be
>> determined, which can not be done if gaps are not included within the
>> dimensions of a voxel.
>>
>> Best regards,
>> -John
>>
>> On 26 September 2010 14:21, Daniel Sodan <[log in to unmask]> wrote:
>> > Hi,
>> >
>> > When I scan with a gap between slices, how this gap is treated during
>> > the
>> > analysis? In the other words, does it enlarge the actual voxel size?
>> > Do I have somewhere in SPM to specify the gap parameter or it is
>> > something
>> > implicit?
>> > What are the pros and cons of a gap usage?
>> >
>> > Thanks for help,
>> > Daniel
>> >
>
>
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