White matter hyperintensities analysis by diffusion tensor images obtained from postmortem in cranium whole brain tissue

Purpose In this paper we aimed at describing the quantifiable properties diffusion tensor images: fractional anisotropy (FA) and Apparent Diffusion Coefficient (ADC) at white matter hyperintensities (WMH) areas found in situ postmortem (PM) specimens. Our hypothesis is that the properties of WMH would be different from normal appearing white matter (NAWM) in the DTI images in postmortem. Materials and methods We analyzed PM MR images from 24 subjects (12 males; mean age: 67.2±14.7 years) and in vivo (IV) MR images from 10 healthy volunteers (5 males; mean age: 62.3±5.49 years). DTI processing was performed using the FSL platform; ROIs were placed at WMH and NAWM at FA and ADC maps. Results PM group presented FA values 26.75% lower at WMH than in NAWM. IV Mean FA in WMH was also reduced (17.76%) compared to NAWM. Average ADC from PM subjects was 6.89% higher at WMH than NAWM and 12.51% higher at WMH than NAWM at IV group. Conclusions We have demonstrated that in situ postmortem FA values at WMH are lower than NAWM, similar to in vivo data. This indicates that DTI obtained at a short postmortem interval from PM MRI could be used to understand in vivo MRI data.