[Mristudio-users] new option save fiber density

[susumu mori]

Hi Venkat,

After fiber tracking, it is a common practice to quantify the results. For
the quantification, the streamline information of the tractography needs to
be converted to pixel information. For this conversion, the simplest way is
to use 1/0 binarilzation. If a pixel contains a streamline, it becomes 1 and
if not, remains 0. This is basically a masking, which can be applied to, for
example, a FA map and get a FA value of the tract. You can also count the
number of pixels with "1" and use it as the tract volume.

One problem of this simple approach is that even if a pixel contains 10
streamlines, the pixel becomes "1", which is the same as another pixel that
contains only 1 streamline. Namely, during the binalization, information
about the density of the streamline is lost. I believe (Hangyi, please
correct me if I'm wrong) "fiber density map" tells how many streamlines were
there in each pixel. You can potentially use it to get, for example,
density-weighted FA value, in which pixels that contain more streamlines are
more weighted than those contain only 1 streamline.

On Fri, Jul 23, 2010 at 6:19 PM, Rajagopalan, Venkateswaran <
rajagov2 at ccf.org> wrote:

>
> Dear All,
>
> I am using DTIstudio_latest_x86.exe after fiber tractography I notices a
> new option named "save fiber density map" (normalized and non normalized). I
> am wondering what information does this fiber density map convey and how
> this information can be used for instance to compare between two groups. How
> the map is normalized.
>
> Thanks
>
> Venkat
>
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