Table 2.

Correlation and agreement across biomarkers in the whole sample and in the whole sample and in subjects within the AD continuum (positive FBP PET)

	Aβ1–42	FBP PET	t-Tau	p-Tau	MRI aHV	MRI ADsig	FDG PET
Aβ1–42		−0.73*	−0.48*	−0.52*	0.42*	0.38*	0.42*
		−0.30*	−0.20*	−0.22*	0.25*	0.25*	0.26*
FBP PET	0.74*		0.58*	0.59*	−0.39*	−0.38*	−0.39*
	-		0.33*	0.32*	−0.25*	−0.27*	−0.29*
t-Tau	0.37*	0.44*		0.76*	−0.36*	−0.38*	−0.39*
	0.09*	-		0.66*	−0.20*	−0.29*	−0.29*
p-Tau	0.33*	0.37*	0.29*		−0.29*	−0.35*	−0.36*
	0.32*	-	0.18*		−0.13*	−0.24*	−0.25*
MRI aHV	0.30*	0.34*	0.28*	0.15ns		0.55*	0.48*
	0.10*	-	0.10ns	0.03ns		0.52*	0.45*
MRI ADsig	0.26*	0.30*	0.31*	0.15*	0.44*		0.49*
	0.08*	-	0.17*	0.07*	0.36*		0.55*
FDG PET	0.29*	0.30*	0.37*	0.13*	0.38*	0.43*
	0.07*	-	0.26*	0.07*	0.32*	0.40*

Abbreviations: ADsig, Alzheimer’s disease signature; FBP PET, [18F] florbetapir positron emission tomography; FDG PET, [18F] fluorodeoxyglucose positron emission tomography; MRI, magnetic resonance imaging.

NOTE. Spearman correlation coefficients are shown above the diagonal. Cohen's Kappa index for each pair of scores are shown below de diagonal; the first line in each box refers to the whole sample (n = 711), whereas the second line refers to the subset of subjects in the AD continuum (n = 397; positive FBP PET); *, P < .05; ns, non-significant.

NOTE. In bold: correlation coefficients and Cohen's Kappa indexes with at least a moderate correlation (Rho > 0.5) or a substantial agreement (k > 0.6), respectively.