[Mristudio-users] Obtaining tract volume data

[Castaneda, Salvador]

Hey,

I did this already. The gradient table was acquired from the header file of the mosaic. The B values were copied in there automatically. I also have placed te b values separated by a comma on the Bvalues, optional Box. I don't understand what the problem is. Thanks
Any other ideas????
Best,

salvador 

-----Ursprüngliche Nachricht-----
Von: Hangyi Jiang [mailto:hjiang at jhmi.edu] 
Gesendet: Donnerstag, 19. Mai 2011 20:07
An: Castaneda, Salvador
Betreff: RE: [Mristudio-users] Obtaining tract volume data

hi,

for multiple b-value dataset, you can define the gradeint table as:  #: x, y, z, b-value
e.g.

0: 1, 0, 0, 600
1: 0,1,0, 600
....
32: 1,0,0, 1000
33: 0,1,0, 1000
...

regards,

hangyi



________________________________________
From: mristudio-users-bounces at mristudio.org [mristudio-users-bounces at mristudio.org] On Behalf Of Castaneda, Salvador [salvador.castaneda at med.uni-tuebingen.de]
Sent: Thursday, May 19, 2011 11:56 AM
To: DTI Studio, ROI Editor,DiffeoMap Questions/Support
Subject: Re: [Mristudio-users] Obtaining tract volume data

Hello Susumu,

I've been using DTIstudio for over a year... It works good. But i just started running a tensor calculation with 4 b values and 256 directions. But it is crashing in the process of the calculation. I'm not requesting any other commands, just the tensor... Do you have any idea what i could do to calculate it... Do i have to analize with less bvalues?
Thanks
salvador

-----Ursprüngliche Nachricht-----
Von: mristudio-users-bounces at mristudio.org [mailto:mristudio-users-bounces at mristudio.org] Im Auftrag von susumu mori
Gesendet: Donnerstag, 19. Mai 2011 17:48
An: DTI Studio, ROI Editor, DiffeoMap Questions/Support
Betreff: Re: [Mristudio-users] Obtaining tract volume data

Hi Melisa,

On Wed, May 18, 2011 at 12:12 AM,  <melcarr at umich.edu> wrote:
> Hello,
>
> I'm attempting to calculate mean tract volume for a tract spanning
> between two ROIs in a subject's FA map.
>
> Is it safe to define tract volume as: the number of voxels between
> both ROIs multiplied by the size of an individual voxel?

This is what we do too.

>
> Does the first measure above ("the number of voxels between both
> ROIs") correspond to the measure "Average Length, mm" in the Fiber
> Statistics window (an example of this window is shown in the User
> Manual, page 26, Figure 19. Fiber-statistics)?

I think the number of voxels occupied by fibers and the average length
of the fibers are very different. The former has unit of mm^3 and the
latter is mm. I don't use the length of fibers for quantification.


>
> Just wondering, thank you.
>
> -Melisa Carrasco
>
> --
>
> Melisa Carrasco, M.S.
> MD/PhD Student, Year Grad-4 (Ph.D. Candidate)
>
> University of Michigan, Neuroscience Graduate Program, Class of 2012
> University of Rochester School of Medicine and Dentistry, Class of 2014
>
> About me: http://sitemaker.umich.edu/melisa.carrasco/home
> GO BLUE!
>
>
>
>
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