[Neuroimaging] [Dipy] Scanning parameters of Dipy's sample data Sherbrooke's 3 shells

[Maxime Descoteaux]

Hi Rafael,

I unfortunately have no trace of the DICOM data anymore.

All I can tell you is that it is 1.5T, Siemens Magnetom, 2mm isotropic. The
TR/TE must have been fixed for the maximal b-value, which explains a lower
SNR at smaller shells that you are probably used to see.

Also, all directions are the same at each shell.

It would be quite easy to share a new dataset from our Philips 3T if you
need.


Max

On Thu, Jul 9, 2015 at 1:57 PM, Rafael Henriques <rafaelnh21 at gmail.com>
wrote:

> Hi Max,
>
> Thanks for your fast reply.
>
> Indeed kurtosis values depend on Delta/delta (e.g.
> http://www.ncbi.nlm.nih.gov/pubmed/23536232), however knowing only the
> basic parameters as TE/TR and voxel resolution should be enough to
> understand what is going wrong with this dataset.
>
> I think that the problem here might be an insufficient SNR for fitting the
> diffusion kurtosis model. From previous datasets that I analysed, I was
> able to obtain decent DKI reconstructions using similar gradient directions
> and b-values, however this was done on a 3T Siemens using a 32 coil head
> channel.
>
> I will give a look to the datasets SNR estimates.
>
> Thanks for your help =),
>
> Rafael
>
>
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