TABLE 3

Mean Percentage Differences (±SD) Between Estimated K_i and Patlak K_i and Spearman Correlation for SKA and ESKA

	SKA_pub		SKA_opt		ESKA		SKA_pub with unmetabolized ¹⁸F-FDG^*		SKA_opt with unmetabolized ¹⁸F-FDG^*		ESKA without unmetabolized ¹⁸F-FDG^*
Group	Mean ± SD	r²	Mean ± SD	r²	Mean ± SD	r²	Mean ± SD	r²	Mean ± SD	r²	Mean ± SD	r²
20 s/55 m (n = 65)	−12% ± 33%	0.82^†	33^‡ ± 36%^§	0.93^†	−7% ± 22%	0.98^†	−40% ± 24%	0.86	−9% ± 22%	0.97	36% ± 33%	0.98
20 s/120 m (n = 8)	−37^‡ ± 19%^§	0.93	−36^‡ ± 20%^§	0.93	−4^‡ ± 6%^§	1.0^†	−47% ± 15%	0.93	−46% ± 16%	0.93	13% ± 6%	1.0
120 s/55 m (n = 51)	20^‡ ± 42%^§	0.94	35^‡ ± 47%^§	0.94	1^‡ ± 29%^§	0.93	−22% ± 20%	0.94	−13% ± 22%	0.93	58% ± 65%	0.93

↵* Results using modifications of 3 methods (SKA_pub and SKA_opt accounting for U_mean or ESKA with U_mean set to 0).
↵† Results for approach significantly different from other 2 in terms of correlation (Fisher r-to-Z transformation).
↵‡ Results for approach significantly different from those of other 2 in terms of mean (Wilcoxon test).
↵§ Results for approach significantly different from those of other 2 in terms of variance (Friedman test).