Deformation‐based morphometry analysis shows early degeneration in Nucleus basalis of Meynert in Alzheimer’s disease

Background Nucleus basalis of Meynert (NbM) is the main source cholinergic projection to cerebral cortex, including entorhinal cortex (EC). Both cells NbM and their receptive targets in EC show degeneration during early stages Alzheimer’s disease (AD). While precise delineation region on T1w scans difficult due limited spatial resolution contrast, we sought quantify along trajectory confirm recent studies suggesting that happens before using deformation-based morphometry (DBM). Method Data included MRI 1473 subjects from Disease Neuroimaging Initiative (ADNI) dataset. Resolution was increased 0.5 mm isotropic voxel-size non-linear registration an ADNI-based unbiased symmetric template. The resulting deformation fields were used compute Jacobian determinant map for each subject as a proxy local volume. masks mapped our high-resolution template mean values inside these calculated groups with different baseline diagnosis, sex- age-corrected z-scores calculated. Two-sample t-tests then compare scores between groups. Result Figure 1 shows DBM score both regions Normal Controls (CN), early- late-stage mild cognitive impairment (EMCI LMCI) probable AD dementia. Results corrected multiple comparisons showed significant difference CN EMCI LMCI left right NbM. A also observed (p-value = 0.0024). Z-scored volumes did not groups; However, results differ significantly hemispheres. We expected differences group (P<0.001). Conclusion Our while macroscopic changes emerge MCI advance toward later stages, starts sooner, preliminary MCI. This points MRI-based measurements potential biomarkers detection marker burden.