NODDI fitting model for ex-vivo brain data

[Rakshit Dadarwal]

 Dear Gary,

I am analyzing the ex-vivo mouse brain dwi data (acquired at bvalues of 3000  and 6000 with 30 gradient directions each) using NODDI matlab toolbox. As suggested for ex-vivo data, I changed the fittting model to 'WatsonSHStickTortIsoVIsoDot_B0' and tissue type to 'exvivo' in noddi matlab script. But estimated maps using above mentioned settings are unusual. 

Then I compared these results to the results fitted by 'WatsonSHStickTortIsoV_B0' model, and found out that  'WatsonSHStickTortIsoV_B0' fitted results were more convincing for my data than  WatsonSHStickTortIsoVIsoDot_B0'.

 
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[Rakshit Dadarwal]

Is it okay to use 'WatsonSHStickTortIsoV_B0' model for my data?

[Hui Zhang]

Can you fit the DTI model to the b=3000 shell, and compute the map of axial diffusivity (AD)?  It will be useful to know what are the AD values in the mid-sagittal slice of the corpus callosum.  This will help inform the model to use.

Gary

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[Rakshit Dadarwal]

Dear Gary,

Thank you for your reply. Please find the attached coronal and sagittal view of axial diffusivity map. Since the slice thickness and slice gap was 0.500mm and 0.250mm, so the sagittal view is blurry.

Thanks

[Hui Zhang]

Ok.  Thanks.  See my reply to Arnold about how to proceed from here.

Gary

[Rakshit Dadarwal]

Dear Gary,

Thank you for your suggestion. As you suggested I made the adjustment to parameters. 

Here model parameter "diso"  is replaced by the mean diffusivity of csf (i.e. 0.6e-09) and parameter "din" by the axial diffusivity (i.e. 0.3e-09). 

But I am getting these unusual results.

 
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best regards

rakshit

[Rakshit Dadarwal]

Dear Gary,

Any suggestion on results that I have shown above.

regards

rakshit