What are the effects of Formalin fixation on MRI values?
T1 and T2-relaxation times significantly decreased, and MWF estimates significantly increased with progressive fixation up to (and likely beyond) the time of our final measurements, 1,032 h.
Despite neither of the diffusion measures (FA nor MD) showing significant changes as a function of formalin fixation time.
These findings imply that in order to prevent formalin-induced changes relative to in vivo values, T1-relaxation, T2-relaxation, and MWF estimates must be performed quite early in the fixation process.
Additionally, different ex vivo scans within an experiment must be acquired at predictable (though still early) fixation intervals in order to prevent fixative-related differences between samples.
