Figure 2.

Correlations between the in vivo brain AChE activity (k₃) by PET and the CSF cholinergic markers. Panel (A) illustrates correlations between the in vivo AChE activity (k₃) overall cortical regions and the CSF ChAT_F activity at 12 months. Panel (B) shows the corresponding correlation with the Cholinergic index in CSF. Graphs C and D show correlations between the in vivo AChE activity (k₃) in the whole brain and CSF ChAT_F activity (C) and the Cholinergic index (D) in CSF at 9–12 months galantamine treatment. The k₃ value has a direct relationship with AChE activity, i.e., a high k₃ value means a high in vivo AChE activity. CSF ChAT_F activity = the overall functional ChAT activity expressed in pmol/min/μg ChAT protein in the samples. CSF AChE_F activity = the overall functional AChE activity expressed in nmol/min/μg AChE protein in the samples. CSF Cholinergic index = ratio of ChAT_F activity to AChE_F in CSF.