Hi - I am having some odd results using dtifit on some of our data.
When I compute FA maps using an older custom program, I get very
reasonable results, with FA ranging from zero to one and with high FA
values where they should be (e.g., corpus callosum). When I run dtifit
on the same data, I get some odd results. First, the FA values in the
corpus callosum are very low. Second, the range of FA values is a bit
strange. Within voxels that are not exactly zero-valued, the minimum
FA value is about 0.35; this compares to our previous results where the
minimum FA value was around .01. In addition, the maximum FA value is
greater than zero (1.15 in this dataset).
Any ideas as to what might be causing this?
Russell A. Poldrack, Ph.D.
Assistant Professor of Psychology, UCLA
Franz Hall, Box 951563
Los Angeles, CA 90095-1563
email: [log in to unmask]