tracking of visual tracts

[Smith]

Hi Frank,

I have done a single shell DTI with b=0 and 1000s/mm2 and along 64 directions. I cannot get the left and right optic tracts while selecting these regions' seeds. Initially, the left optic tract had 172 tracts in the tracts column; after that, it went to the deleted column(see attached picture). Please provide some suggestions to rectify this.

In this group. let me know if anyone is doing visual tracts. Please suggest some relevant articles and connect with me. I am doubting whether there is any problem with my acquisition protocol. please see the protocol

TR=8643, TE=103.1, Flip angle =90, No of Averages=1, Slice thickness =2, slice spacing =3, voxel size=1x1, image rows and columns = 256x256, No of volumes :65, No of slices =42 and number of files = 2730.

Thanks and Regards

Smitha

[Frank Yeh]

On Tue, Nov 19, 2024 at 4:21 PM Smith <smitha....@gmail.com> wrote:
>
> Hi Frank,
> I have done a single shell DTI with b=0 and 1000s/mm2 and along 64 directions. I cannot get the left and right optic tracts while selecting these regions' seeds. Initially, the left optic tract had 172 tracts in the tracts column; after that, it went to the deleted column(see attached picture). Please provide some suggestions to rectify this.

In the option on the right upper corner under the tracking parameters,
change topology informed pruning to 0.

[Smith]

Thanks, Frank, I will check it out and let you know,

[Smith]

Dear Frank,

I have set the topology informed pruning to 0 and tried the automated tractography for Optic radiation and CNII , I am attaching the figures. 

Regards

Smitha

[Frank Yeh]

The result is not ideal.

The resolution needs 2 mm isotropic resolution.

The b value is a bit low. It needs a higher b value greater than 1500.

Please check out example data shown at practicum.labsolver.org and see how to map major pathways.

best

Frank

[Smith]

Dear Dr Frank,

I will be doing DTI with more than 1500 b value and 2mm isotropic resolution. By the time we acquired another data with 30 directions, reverse phase encoding directions, slice thickness 2mm, isotropic resolution- 0.9063 mm. Please see the tracts OR and CNII obtained using automatic tractography. Seeds are 1000000. Topology informed pruning set to zero.