Table 1. BP_ND estimates were compared using two-tailed t-test: (a) for each reference tissue method are given the significance levels for testing differences in the clinical subject groups; (b) for each clinical subject group are given the significance levels for testing differences in the reference tissue methods.

Test	RPM cerebellum	RPM SVCA4	RPMVb SVCA4	RPM SVCA6	RPMVb SVCA6
(a)
YC versus OC	0.266	0.000	0.000	0.025	0.004
YC versus MCI	0.167	0.019	0.004	0.142	0.017
YC versus AD	0.137	0.000	0.000	0.007	0.005
OC versus MCI	0.779	0.690	0.452	0.519	0.581
OC versus AD	0.911	0.295	0.050	0.209	0.435
MCI versus AD	0.809	0.299	0.039	0.144	0.286

Test	YC	OC	MCI	AD
(b)
RPM CER versus RPM SVCA4	0.002	0.000	0.001	0.000
RPM CER versus RPMVb SVCA4	0.030	0.008	0.241	0.000
RPM CER versus RPM SVCA6	0.078	0.000	0.021	0.000
RPM CER versus RPMVb SVCA6	0.013	0.499	0.195	0.803
RPM SVCA4 versus RPMVb SVCA4	0.000	0.001	0.022	0.021
RPM SVCA4 versus RPM SVCA6	0.153	0.000	0.026	0.002
RPM SVCA6 versus RPMVb SVCA6	0.001	0.000	0.003	0.003
RPMVb SVCA4 versus RPMVb SVCA6	0.628	0.002	0.075	0.000

BP_ND, binding potential; CER, cerebellum; RPM, reference tissue model; RPMV_b, RPM with vascular correction; SVCA, supervised cluster analysis.

Data were taken from young controls (YC), old controls (OC), and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Significant P values are indicated with bold fonts.