Hello all,

I am conducting some research that involves quantifying in vivo spinal cord
motion using MR-based images. I have done a fair bit of literature search,
looking for studies that have effectively utilized small (~0.2mm diameter is
the size required for my study) fiducial markers in any type of Central
Nervous System (CNS) tissue, but unfortunately I have not come up with
anything. I have already conducted some preliminary work to test the
efficacy of a number of different materials but the results have not been
acceptable, as MR susceptibility artifacts create 'voids' in the generated
signal, up to 4 times the actual diameter of the fiducial, resulting in post
image-processing issues. Although I'm sure there may be suggestions of
different ways I could quantify this motion, I need somewhat of a 'gold
standard' for my study (which involves creating a non-invasive measuring
technique), and I believe fiducial markers are as close to 'gold' as I can

If anyone can point me to a study they may be familiar with, I would be
over-joyed - again, the key issue here is the size of the fiducials; there
are many MR-compatible materials that will cause relatively small
susceptibility artifacts, but even 'small' susceptibility artifacts are
problematic in my study. Additionally, if anyone can recommend any
unpublished or non-peer reviewed work, I would still jump at the opportunity
to possibly determine an appropriate fiducial material for my study.

Many thanks - as is common, I will gladly post a summary of responses I

Tim Bhatnagar
PhD Candidate
Mechanical Engineering
University of British Columbia