[Mristudio-users] philips rec-par gradient table

[susumu mori]

As Ming-Ru said, you need to rearrange your table.
I assume that you are using a user-defined gradient table.
Even if you specified in your gradient table that the first image would be
[0, 0, 0], Philips scanner has two options to store the data; 1) b0 in the
beginning or 2) b0 in the second from the last.

In Philips scanner, the last image is always a calculated
diffusion-weighted image, which should be discarded for tensor calculation.
If you don't see that the b0 is not the first image in the file, you chose
the second option.

If your original gradient table was;

0: 0, 0, 0
1: 1, 0, 0
....
30: 0, 0, 1

There are two possibilities;

If the b0 is the first image;
0: 0, 0, 0
1: 1, 0, 0
....
30: 0, 0, 1
31: 100, 100, 100

Note that I added one extra raw, which send DtiStudio a message that 32nd
image has to be discarded.

If the b0 is not the first image;

0: 1, 0, 0
....
29: 0, 0, 1
30: 0, 0, 0
31: 100, 100, 100

Susumu


On Wed, Feb 20, 2013 at 9:25 AM, 莊 明儒 <min4135 at hotmail.com> wrote:

>  Hi
>
> I think that you just need to re-arrange your gradient table according
> to the diffusion weighted directions.
>
> It will work normally.
>
> Ming-Ru
>
> ------------------------------
> From: licia_p at hotmail.com
> To: mristudio-users at mristudio.org
> Date: Wed, 20 Feb 2013 14:14:20 +0000
> Subject: [Mristudio-users] philips rec-par gradient table
>
>
>
>
> Good Morning,
>
> I'm having a problem with DTI mapping in DTI studio. B0 is the 30th image
> in my REC file and the in standard gradient table for PAR-REC files it is
> the first (0,0,0). What should I do? Should I change the order of gradient
> lines from 0 to 30th? Or is there another gradient table?
>
> Thanks in advance!
>
> Licia
>
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