Table 3.

P-values for group-wise differences in global cortical PIB and ventricular volume

		Pairwise by diagnosisa
Variable	Differences among three groupsb	CN versus aMCI	CN versus AD	aMCI versus AD
Global cortical to cerebellar PIB ratio
Baseline	0.01	0.02	0.003	0.40
Annual change	0.90	0.79	0.90	0.65
Ventricular volume
Baseline volume,% of TIV	0.19	0.39	0.04	0.31
Annual change, cm3	<0.001	0.01	<0.001	0.004

Mayo and ADNI data have been combined. CN = cognitively normal; aMCI = amnestic mild cognitive impairment; AD = Alzheimer's disease.

a Two-group Wilcoxon rank sum test.

b Three-group Kruskal–Wallis test.