HI Ed,
I believe that you are referring to the RA measure of anisotropy.
FA is theoretically limited to the range 0-1.
FA's greater than 1 can arise when you have negative estimates of the
eigenvalues, which can arise when using linear least squares estimation
of the tensor.
cheers,
-MH
On Fri,
Dear Antonella,
In theory, FA can be sqrt(3/2) = 1.2247449. This occurs if
eigenvalues 2 and 3 are zero. You will find these high
FA values (>1) mainly outside the brain.
Ed
On 3 Feb 2012, at 11:31, freesurfer-requ...@nmr.mgh.harvard.edu wrote:
Dear all,
I use dt_recon to process my DTI dat
Dear all,
I use dt_recon to process my DTI data and get my fa.nii for the individual
subjects. I wonder if the FA values can be greater that one since for all my
subjects I got the FA max value graeter than one. Is something wrong with my
data or this is acceptable? I saw in most of the paper
