Fig. 4
From: Centiloid cut-off values for optimal agreement between PET and CSF core AD biomarkers
Derivation of amyloid PET Centiloid cut-offs for CSF tTau/Aβ42. Top row shows scatterplots of PET quantitative measures in Centiloids against CSF tTau/Aβ42 biomarker values for both ALFA+ (blue) and ADNI (red) participants. Vertical line depicts previously published CSF thresholds (tTau/Aβ42 0.26 [22, 30]), and horizontal lines depict optimal cut-offs derived in this study (YI derived: green, OPA derived: yellow). Two outliers were excluded of this picture for having CL value higher than 200. Second row shows this cut-off derivation by maximization of YI (left) and OPA (right). The YI (green) was calculated from PPA (blue) and NPA (red) values. The OPA (green) was calculated from PPV (blue) and NPV (red) values. Derivation was done with participants of both cohorts merged. tTau, total tau; CSF, cerebrospinal fluid; YI, Youden’s J index; PPA, positive percentage agreement; NPA, negative percentage agreement; CL, Centiloids