[Mrtrix-discussion] DWI Data with 35 directions and b=1000

[J-Donald Tournier]

Hi Linden,

For tckgen, we've made sure the defaults work more or less out of the box,
and wouldn't generally recommend changing these unless you have good
reasons for it. What is more important is to ensure that the FODs that you
provide to tckgen are robust. So the parameters you need to worry about are
those to dwi2response and dwi2fod. Again, unless your data are more exotic
than the upfront parameters suggest, I wouldn't change the defaults for
those either. The main issue I'd be worried about there is a suboptimal
distribution of directions, making the higher harmonic orders unstable, or
the presence of repeat directions, which would basically cause the same
problem. But assuming there's no issues with the data (other than its
b-value & number of directions), it should work fine...

Now, if you've already tried running these commands with default
parameters, and the results are no good, then sure, you'd need to figure
out why and see what can be done about it. But we'd need more information
if you want us to help you out...

Cheers,
Donald

--
Dr J-Donald Tournier (PhD)

Senior Lecturer, Biomedical Engineering
Division of Imaging Sciences & Biomedical Engineering
King's College London

A: Department of Perinatal Imaging & Health, 1st Floor South Wing, St
Thomas' Hospital, London. SE1 7EH
T: +44 (0)20 7188 7118 ext 53613
W:
http://www.kcl.ac.uk/medicine/research/divisions/imaging/departments/biomedengineering

On 18 Dec 2014 23:46, "Linden Parkes" <linden.parkes at monash.edu> wrote:

> Hi,
>
> I’m looking for some advice on which -algorithm to use with tckgen on my
> data (parameters in subject line).
> I’ve read on this list that at least 30 directions is sufficient but I see
> that my b=1000 is probably less than optimal.
>
> Cheers,
> Linden
>
> ——————————————————————
>
> Linden Parkes
>
> PhD Candidate
> Monash Clinical & Imaging Neuroscience (MCIN)
> School of Psychological Sciences
> Monash Biomedical Imaging
> Monash University
>
> A: 770 Blackburn Rd, Clayton, 3168, Vic, Australia
> T: +61 3 9902 9807  |  0402 516 574
> E: linden.parkes at monash.edu
> W: www.med.monash.edu.au/psych/mcin/
>
>
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