MAPT and Brain atrophy: Each modality captures distinct, often complementary, facets of AD pathophysiology; for instance, sMRI delineates patterns of brain atrophy (visible in Fig. 4), PET can reveal metabolic dysfunction or specific proteinopathies (amyloid-beta as in Fig. 6, tau), and CSF analysis offers direct biochemical evidence of these pathological proteins [102, 148, 169].