[Mristudio-users] Regarding gradient table

[Santosh Yadav]

Thanks Dr. Susumu.

So for taking the exact correct gradient table, for example I should
extract gradient table from DICOM files using DTI studio having the option
called (Get gradient from DICOM file header) or gradient file from the
scanner. Since i have the discrepancy between gradient file obtained from
scanner provided by manufacturer and extracted from DICOM file header using
DTIstudio. Which one is more accurate?

With best Regards,

Santosh






On Fri, Apr 12, 2013 at 4:10 PM, susumu mori <susumu at mri.jhu.edu> wrote:

> Hi Santosh,
>
> If the gradient table is wrong, all calculation would be wrong.
> There is a mistake that could be corrected after the calculation but it is
> only when the +/- sign of entire column (say, y-component column) of the
> table is wrong. In this case, I think FA/MD are not affected but the vector
> signs are flipped. So you can flip the sign of the y-components before
> tracking. This rule is, however, no longer valid when you do gradient table
> rotation for oblique-imaging or you rotate the image for image registration.
>
>
>
> On Fri, Apr 12, 2013 at 6:28 PM, Santosh Yadav <
> santoshyadav20076 at gmail.com> wrote:
>
>> Hi Dr. Susumu,
>>
>> I have one question regarding gradient table in calculation of DTI metric
>> and fiber tractography.
>>
>> Is gradient table have only effect on fiber tractography and doesn’t
>> affect ADC and FA values, Is this correct?
>>
>> With best Regards,
>>
>> Santosh
>>
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-- 
With Best Regards,

Neuroscience and MR Research Program

Department of Medicine, Queen's Medical Center

University of Hawaii

1356 Lusitana Street, 7th Floor, Honolulu, HI 96813

Phone No. 808-220-7152

Fax No.  808-545-8970
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