[Insight-users] Confusion with direction cosines in DICOM, tag 0020|0037

[Patrik.Br.]

Hello,

I was wondering how to use the direction cosines in DICOM when contructing a
direction/rotation matrix. Should the six numbers in tag 0020|0037 represent
the first two columns or the first two rows of the matrix?

An ITK bug report suggests (i think) that they are the first two row
vectors:
http://www.cmake.org/Bug/view.php?id=7748

...but some nifti documentation seem to state the opposite (down the bottom
of the page):
http://nifti.nimh.nih.gov/nifti-1/documentation/nifti1fields/nifti1fields_pages/quatern.html

A short educational pdf-document implies they are the row vectors of the
matrix:
http://www.ae.uiuc.edu/~tbretl/ae403/handouts/06-dcm.pdf

...but wikipedia seems to state that they should be interpreted as the
column vectors of the matrix:
http://en.wikipedia.org/wiki/Rotation_representation_(mathematics)#Rotation_matrix_.28or_direction_cosine_matrix.2C_DCM.29

Can someone de-confuse me?!

Thanks in advance,

//Patrik
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