Miguel,
We use the tables generated by dcm2nii and they seem good. For the other table source, are you using tensor.dat that is in /usr/g/bin off the scanner? [ Of course now I wonder about ours ].
What you could do is run a phantom rather quickly. Go down to your grocer and pick up some celery, make some fresh cuts, put in water in a water tight seal, you can even add some gadolinium to short the T1 and take some images. It should show up. The phloem's are high anisotropic.
It'll be low-res (run as high res as possible), but we've done this in the past many, many times.
-Robert
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Robert C. Welsh, PhD
Research Assistant Professor
Departments of Radiology and Psychiatry
University of Michigan
(734) - 764 - 8541 (fax)
(734) - 647 - 6781 (Ofc)
rcwelsh @ med.umich.edu
>>> Miguel Burgaleta <[log in to unmask]> 09/29/09 12:27 PM >>>
Dear FSL group,
I have a beginner's question regarding the gradient table that I should use
with my DTI. The scanner is a GE and I already have the standard medium
table from the manufacturer, but I get weird FA colormaps when using it
(non-symmetric, corpus callosum not red). However, if I use a gradient table
made by reading the DICOM headers with dcm2nii, I get a gradient table that
leads to symmetric, solid red CC FA colormaps. I have heard that this is a
good criterion to make sure that the gradient table is the right one, but
also heard that it could be incorrect too! So the question is how to make
sure that the gradient table is the right one?
I appreciate your help + apologize if this message is beyond the scope of
this list.
Miguel
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