Like tau‐PET, baseline CSF Aβ42/40 demonstrated a mildly significant relationship with FDG–PET SUVR in subjects with MCI (r = 0.137, p = 0.026), while no significant association found among CN (r = 0.108, p = 0.294) and AD subjects (r = −0.046, p = 0.750, Figure 4C). Here, MAPT is linked to Alzheimer disease.