[Mrtrix-discussion] question about CSD

[Donald Tournier]

Hi Michael,

Actually, I would have thought it would be the opposite: a structure
entirely through plane would be resolved better. That said, I can't
think of any studies that have looked at that specifically, so don't
quote me on that... Maybe someone else on the list can suggest an
appropriate reference...?

Cheers,

Donald.


2010/1/18 Michael Zeineh <mmzeineh at gmail.com>:
> Thank you Donald.
>
> I see. So, for the example an axial DTI with thick slices but small in
> plane voxels, a structure entirely in-plane would be resolved better
> than if the same object were entirely through-plane (assuming things
> like SNR are similar).
>
> Michael
>
> On Sun, Jan 17, 2010 at 3:18 PM, Donald Tournier
> <d.tournier at brain.org.au> wrote:
>> Hi Michael,
>>
>> Yes, it should work with anisotropic voxels (although isotropic would
>> always be recommended). There is little point interpolating (at least
>> not using linear interpolation), since the tracking code performs
>> linear interpolation while tracking. In terms of bias, the
>> orientations are provided with respect to real (scanner) coordinates,
>> so do not depend on the voxel dimensions. There would however be a
>> bias when tracking WM structures oriented predominantly through-plane
>> versus in-plane, since the "effective resolution" would be higher in
>> the first case. This applies to all tracking methods though, not just
>> MRtrix (and is not a limitation of the CSD itself).
>>
>> Hope that helps,
>>
>> Donald.
>>
>>
>> 2010/1/16 Michael Zeineh <mmzeineh at gmail.com>:
>>> Out of curiosity, will it work on anisotropic diffusion data (i.e.
>>> voxels are thicker along one axis)? If so, would there be any expected
>>> errors or biases? Would simple interpolation (somewhat) resolve those
>>> issues?
>>>
>>> Thank you,
>>> Michael
>>> _______________________________________________
>>> Mrtrix-discussion mailing list
>>> Mrtrix-discussion at www.nitrc.org
>>> http://www.nitrc.org/mailman/listinfo/mrtrix-discussion
>>>
>>
>>
>>
>> --
>> Jacques-Donald Tournier (PhD)
>> Brain Research Institute, Melbourne, Australia
>> Tel: +61 (0)3 9496 4078
>>
>



-- 
Jacques-Donald Tournier (PhD)
Brain Research Institute, Melbourne, Australia
Tel: +61 (0)3 9496 4078