[Mristudio-users] Tensor calculation

[susumu mori]

It is a common practice to perform 12-mode affine before tensor
calculation. If your scanner doesn't have noticeable eddy current (like
many modern Siemens), you can do 6-mode rigid just for motion correction.

On Mon, Jun 25, 2012 at 4:18 PM, Santosh Yadav
<santoshyadav20076 at gmail.com>wrote:

> Dear Dr Hangyi,
>
> Lot of thanks for great response.
>
> I have another question regarding DTI processing.
>
> I am processing the DTI data acquired from Siemens 3T for LDDMM, Is it
> necessary/important step to do the Automatic image registration using a
> 12-mode affine transformation before tensor calculation?
>
> As I read the articles, It is important step for motion and eddy current
> distortion correction in the DTI data.
>
> Ref.
> 1. Neuroimage 2009; 47(2): 618-627
> 2. Jiang H<http://www.ncbi.nlm.nih.gov/pubmed?term=Jiang%20H%5BAuthor%5D&cauthor=true&cauthor_uid=16413083>Comput Methods Programs Biomed. 2006, 81(2):106-16
>
>
> With Best Regards
>
> Santosh
>
>
>
> On Mon, Jun 25, 2012 at 4:50 AM, Hangyi Jiang <hjiang at jhmi.edu> wrote:
>
>>
>> there is no standard answer for your question, it depends on original
>> dataset.  the following recommends are just for your reference:
>>
>> if your dataset has only few diffusion orientations (e.g. less than 8),
>> you may try:
>> manual image quality check + standard linear fitting or outlier pixel
>> rejection method;
>>
>> if you have only few subjects to study, you way try:
>> manual image quality check + standard linear fitting;
>>
>> if your dataset have a lot of DW orientations (e.g. more than 15), you
>> can try:
>> outlier slice rejection method;
>>
>> if you find motion artifact, you can  use AIR based method.
>>
>> and......
>>
>> best,
>>
>>
>> hangyi
>>
>>
>>
>>
>>
>>
>>  or outlier pixel rejection method;
>>
>>
>> ________________________________
>> From: mristudio-users-bounces at mristudio.org [
>> mristudio-users-bounces at mristudio.org] on behalf of Santosh Yadav [
>> santoshyadav20076 at gmail.com]
>> Sent: Sunday, June 24, 2012 4:24 AM
>> To: DTI Studio, ROI Editor, DiffeoMap Questions/Support
>> Subject: [Mristudio-users] Tensor calculation
>>
>>
>> Hello DTI Experts,
>>
>> I want to know which method is good for tensor calculation using
>> DTI-Studio for LDDMM.
>>
>> In DTI-Studio, for tensor calculation there are four methods:
>>
>> 1. Standard linear registration
>> 2. Automatic outlier SLIC rejection
>> 3. Automatic outlier pixel rejection method
>> 4. AIR for theory-original DWI pair with using a 12-mode affine
>> transformation (Woods et al., 1998)
>>
>> I read few articles which described the tensor calculation by using AIR
>> for theory-original DWI pair Method (Method 4) (Neuroimage 2009; 47(2):
>> 618-627, Neuroimage 2009; 46(2): 486-499), is this method having any
>> advantage over Automatic outlier pixel rejection method?
>>
>> With Best Regards
>>
>>
>> --
>> 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
>>
>>
>>
>>
>
>
> --
> 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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