open-discussion > Siemens Trio coordinate flipping
May 21, 2013  12:05 PM | Paul Enggruber
Siemens Trio coordinate flipping
Hello!

When I feed my scanner with gradient directions eg. direction.txt:
Vector[0] = (0.00000000, 0.00000000, 0.00000000 )
Vector[1] = (0.57735027, 0.57735027, 0.57735027 )
it produces an dicom output which has flipped signs on y,z and slightly different values:
DICOM-Header:
0\0\0
0.57657135\-0.5817965899999999\-0.57365328
which I think should have a reason. Incorporated interaction with readout gradients?
When I convert the dicom file via dcm2nii it flips the y sign again: dm2.nii.txt:
0 0 0
0.57657140493393 0.58179664611816 -0.57365334033966
the small difference in the values should be caused by different rounding algorithms and can be neglected, I think.
Did you have similiar problems? Is their any literatur on that issue? Any great ideas ;-) ?
Cheers
Paul