NEFL and brain infarction: Five, Plasma NFL has not been compared with any established independent biomarkers of potential AD pathology (e.g. CSF AD biomarker, PET AD biomarker) and is also a limitation of the current study; Finally, since the current study did not include other diseases, including cerebral infarction, cerebral hemorrhage, etc., whether NFL can be used as a biomarker for AD still needs to be further studied and explored.Finally, only 12 of the 103 AD patients met the conditions for PET CT or cerebrospinal fluid AB42 protein positivity, which is a major limitation of the study.