[Mristudio-users] Gradient table

Fri May 1 10:39:11 EDT 2009

Following link will be a bit of help.
http://godzilla.kennedykrieger.org/~jfarrell/OTHERphilips/GUI.html<http://godzilla.kennedykrieger.org/%7Ejfarrell/OTHERphilips/GUI.html>

You need to have JAVA runtime on your computer.

Use your examcard when you filling the boxes provided in the link.
You will have a gradient table.
Overplus-On option will give you different gradient table for each different
angulation info.
Overplus-Off option will give you the same result no matter what angulation
info. Only difference comes from directional resolution.

-SC

On Sat, Apr 18, 2009 at 2:42 PM, liang wang <wanglbit at gmail.com> wrote:

> Dear Susumu,
>
> I also have a similar question about gradient tables in Philips scanner.
>
> My data were collected using following protocols:
> 1) Gradient table: Medium
> 2) Gradient overplus: no
> 3) Oblique plane: yes, and different angles between subjects.
>
> Looking through your answer, I know that this set can result in the same
> gradient table input into DTIstudio for all subject. However, 1) I am not
> sure which coordinates (space) the ultimate gradient table was relative to,
> such as frequency- and phase-encoding of image, horizontal and vertical
> direction of image, or magnets' x/y/z coordinates. Based on your reply, I
> think that it might be the last one.
>
> 2) In my *.PAR file, there was last 3 columns representing diffusion
> directions but obviously different between subjects. I don't know what
> diffusion were recorded in this header file.
>
> Many thanks
>
> Liang
>
> 2009/4/16 susumu <susumu at mri.jhu.edu>
>
>>  Hi Eric,
>>
>>
>>
>> For Philips scanner there are several types of gradient tables you can
>> specify in the scanner. Please check your protocol for the following points;
>>
>>
>>
>> 1)       Gradient table: High (32-orientation)/ Medium (15-orientation) /
>> Low (6-orientation)
>>
>> 2)       Overplus (ON / OFF)
>>
>> 3)       Oblique plane (X/Y/Z angles)
>>
>>
>>
>> The first option has 3 choices and the second option has 2 choices.
>> Therefore, there are 3 x 2 = 6 gradient tables.
>>
>> If the second option (Overplus) is NO, the third option has no effect. If
>> the second option is YES, the gradient table has to be rotated based on the
>> oblique angles.
>>
>>
>>
>> To simplify the DTI processing, we recommend Overplus = NO.
>>
>>
>>
>> We have the basic 6 tables, which can be used as is if you use Overplus =
>> OFF or Oblique angles = 0/0/0 degree.
>>
>> Please let us know which options you are using.
>>
>>
>>
>> Susumu
>>
>>
>>  ------------------------------
>>
>> *From:* mristudio-users-bounces at mristudio.org [mailto:
>> mristudio-users-bounces at mristudio.org] *On Behalf Of *eric Q
>> *Sent:* Thursday, April 16, 2009 9:44 PM
>> *To:* mristudio-users at mristudio.org
>> *Subject:* Re: [Mristudio-users] Gradient table
>>
>>
>>
>> Hello Dear DTIstudio users:
>>
>> I am new to DTIstudio, I was hoping someone could give me some much needed
>> advises for beginners.
>>
>>
>> I was trying to obtain the FA values for my brain phantom (PHILIP 3T
>> scanner). When I clicked on "DTI mapping", it prompted me to enter the
>> "gradient table", how do I calculate the "gradient table"?
>>
>> Thanks in advanced
>>
>> Best regards
>>
>> Eric
>>
>>
>>  ------------------------------
>>
>> Date: Thu, 9 Apr 2009 11:04:09 -0400
>> From: susumu at mri.jhu.edu
>> To: mristudio-users at mristudio.org
>> Subject: Re: [Mristudio-users] MriView3D application close
>>
>> Hi Hugh,
>>
>>
>>
>> When you got this error, please suspect one of the following two reasons;
>>
>>
>>
>> 1) Memory shortage:
>>
>>
>>
>> Even if you have many GB of memories, 32-bit Windows system can allocate
>> only 1 - 1.5 GB to each program. To check if you have the memory problem,
>> please restrict the slices to be calculated. In the initial data parameter
>> window, there is a section called "Slices to be processed". Here you can
>> specify only a portion of slices to be processed. Please limit the slices
>> to, for example, 0-9 and see how it goes. If you can calculate tensors
>> without errors, then you have the memory problem. The solution is; a)
>> upgrade to the 64-bit system or b) devide the calculation to 2 batches (e.g.
>> slice 0-29 for the first batch and 30-59 for the second batch), calculate
>> all maps (e.g. FA), and later combine them.
>>
>>
>>
>> 2) Mismatch between the gradient table and the number of images:
>>
>>
>>
>> For example, if you specify 12-orientation table and 30 volume images,
>> then you get the error. After loading the data and before you go to the Dti
>> Map tab, make sure that you have 1 b0 + 64 DWIs in the pull-down menu in the
>> right column of the Image tab. If you have the correct number of the images,
>> then you might have an error in your gradient table. Small mistakes such as
>> missing "," are often difficult to detect. The best way is; a) load the data
>> using DtiMapping under the "File" button on the top left, b) close the
>> window, c) open the image paremater window again by clicking "DtiMapping" in
>> the "File" button again, d) the window still remembers the gradient table
>> you entered last time. This remembered window tells how DtiStudio
>> interpreted your gradient table. If there is any syntax errors, you may find
>> them much easier. For example, if you enter, "4: 1 0.5 0", instead of "4: 1,
>> 0.5, 0", then you would find, "4: 1, 0, 0".
>>
>>
>>
>> If any of these do not solve the issue, please let us know.
>>
>>
>>
>> Susumu
>>
>>
>>  ------------------------------
>>
>> *From:* mristudio-users-bounces at mristudio.org [mailto:
>> mristudio-users-bounces at mristudio.org] *On Behalf Of *Hugh Wang
>> *Sent:* Wednesday, April 08, 2009 6:30 PM
>> *To:* mristudio-users at mristudio.org
>> *Subject:* [Mristudio-users] MriView3D application close
>>
>> Hi,
>>
>> I was using the dtistudio (ver. 2.4)  to look at the Siemens DICOM
>> diffusion images (1baseline,64 gradients). After successfully loading the
>> images, I click the "dti map" option at lower right corner. Whatever
>> calculation I choose, it always gives me an error:
>>
>> "MriView3D MFC Application has encountered a problem and needs to close.
>> We are sorry for the inconvenience."
>>
>> I tried several PCs, and the problem keeped the same. I would appreciate
>> that if there's anyone having any idea on how to solve it. Thanks.
>>
>> Best,
>> Hugh
>>  ------------------------------
>>
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>
>
> --
> Liang Wang, PhD
> Postdoctoral Fellow
> Woodward Lab
> Department of Psychiatry
> University of British Columbia
> BC Mental Health & Addiction Services
> 938 West 28th Avenue
> Vancouver BC V5Z 4H4
> Telephone: 1-604-875-2000 (ext. 4735)
> Fax: 1-604-875-3871
> Email: wanglbit at gmail.com
>
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