[Insight-users] GE diffusion data - extract orientation from DICOM header

[Michael Scheel]

Hi everybody,

i have a question if anybody can give me some advise on a problem with  
a DTI series acquired on a General Electric Signa 3T.
I have the DICOM dataset and the file for the gradient directions in  
the Scanner Coordinates.
To avoid artefacts we aquired the data parallel to a plane (frontal  
sinus - cerebellum) - that gives quite a big angulation of the xy-plane.

What I need to do is to take into account this angulation and correct  
the gradient-direction-file.
My problem is that I don't know how to extract the amount of  
angulation from the DICOM header.

So I guess my question boils down to:

How do I extract the angulation parameters from the DICOM header and  
use it to correct the gradient-direction-file?

Here is what the header says:
....
ImagePositionPatient (0020,0032) -129.492\-147.271\35.8859
value -129.492
value -147.271
value 35.8859
ImageOrientationPatient (0020,0037) 1\-0\0\-0\0.844841\-0.535018
value 1
value -0
value 0
value -0
value 0.844841
value -0.535018
.....

I just don't know how to translate this, especially why are there 6  
values for the orientation when there are 3 planes that can be  
angulated?

Thanks a lot, Michael.