[Insight-users] CSI spectro parameters

[Vincent A. Magnotta]

Stefano,

I would expect that you would actually need 9 parameters to describe the
location and orientation of the CSI data using the DICOM standard. Three
of the parameters would describe the position of the location of the
first CSI voxel and the other 6 the direction cosines. If you would dump
the DICOM header you should be able to get this information. The header
information that you are reading appears to be the Siemens shadow fields
and there is probably a limited description of the meaning of this
information in the community. You will probably need to talk to a
Siemens Scientist to get more information regarding the meaning of these
fields. 

Vince
   

On Fri, 2007-02-23 at 16:40 +0100, Stefano Peca wrote:
> Hi everyone, please help if you can!
>  
> I have a multi-voxel magnetic resonance spectroscopy file (CSI -
> chemical shift imaging) and a T1 volume, many slices.  I need to know
> where exactly is the CSI grid (8x8 1ml voxels) in respect to the T1
> volume.
>  
> I'm using a Siemens Allegra Magnetom 3T.
>  
> The CSI dicom file has this information in the header:
>  
> sSpecPara.sVoI.sPosition.dSag            = -14.6151885
> sSpecPara.sVoI.sPosition.dCor            = 67.89309338
> sSpecPara.sVoI.sPosition.dTra            = -25.70038393
> sSpecPara.sVoI.sNormal.dSag              = -0.4226182617
> sSpecPara.sVoI.sNormal.dCor              = 0.906307787 
> (sSpecPara.sVoI.sNormal.dTra              = 0.00307856 )
>  
> but I don't know how to interpret it. They must somehow describe how
> the CSI grid is oriented...  if, for instance, the first 3 of these 5
> header lines describes a position (maybe of the center of the grid),
> the question is: in respect to what? to the high definition T1 image
> on which the CSI slice was positioned, or to the center of the magnet?
>  
> Well, if someone knows what these 5 numbers are  (occasionaly there
> are 6) , I'll be very grateful,
> Thanks very much,
> Stefano Peca
>  
> Dr. Stefano Peca - MARBILab - "Enrico Fermi" Center @ Fondazione Santa
> Lucia - V.Ardeatina 306 - Roma, Italy - Tel.: +39 06 5150 1524 - Fax:
> +39 06 5150 1528 - stefano.peca at roma1.infn.it -
> 
>  
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-- 
Assistant Professor
Department of Radiology
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E-mail: vincent-magnotta at uiowa.edu
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