Investigating Postmortem Neurite Orientation Dispersion and Density Imaging Parameters and Their Influences on Deceased Human Brains

Motivation: Neurite orientation dispersion and density imaging (NODDI) is expected to advance our still incomplete understanding of diffusion properties in postmortem brains. Goal(s): We examined NODDI parameters in deceased human brains in situ and investigated their associations with postmortem interval (PMI), age at death and core temperature. Approach: Ten subjects underwent postmortem in situ brain MRI, enabling NODDI analysis. Correlations between NODDI parameters and external factors were assessed. Results: The results revealed higher NODDI parameters in deceased compared to living subjects. Longer PMIs were associated with increased fractional intracellular volume (FICVF) and orientation dispersion index (ODI) values, while higher temperatures had the opposite effect. Impact: Our study expands the understanding of postmortem brain microstructure. NODDI's potential in deceased brain analysis and its relation to postmortem interval and temperature pave the way for further research with applications in diagnostics and forensics.