TABLE 2

Parameter Estimation

Model	Region	K₁ (mL cm⁻³ min⁻¹)	k₂ (min⁻¹)	k₃ (min⁻¹)	k₄ (min⁻¹)	V_T (mL/cm³)	BP_ND	BP_P (mL/cm³)	Akaike information criterion	Relative diff BP_ND (%)	Average diff BP_ND (%)	ICC BP_ND	Relative diff BP_P (%)	Average diff BP_P (%)	ICC BP_P
1-TC	Cerebellum	0.19 ± 0.07	0.023 ± 0.003	—	—	7.86 ± 2.23	—	—	586 ± 20	—	—	—	—	—	—
	Parietal ctx	0.19 ± 0.07	0.016 ± 0.003	—	—	11.8 ± 3.26	0.51 ± 0.10	3.97 ± 1.22	542 ± 26	7.50	13.2	0.82	11.6^*	10.7	0.88
	Sup. fr. ctx	0.19 ± 0.07	0.016 ± 0.003	—	—	11.3 ± 3.17	0.43 ± 0.10	3.39 ± 1.16	541 ± 23	8.08	12.5	0.87	12.2^*	9.70	0.89
	Hippocampus	0.17 ± 0.06	0.010 ± 0.002	—	—	16.2 ± 4.59	1.07 ± 0.21	8.38 ± 2.63	569 ± 13	6.27	13.0	0.80	10.4^*	7.53	0.91
	Striatum	0.23 ± 0.08	0.006 ± 0.002	—	—	40.4 ± 11.7	4.20 ± 0.93	32.5 ± 10.1	536 ± 27	11.4^†	8.2	0.84	15.5^*	8.69	0.80
2-TC	Cerebellum	0.24 ± 0.08	0.056 ± 0.009	0.021 ± 0.006	0.018 ± 0.003	9.50 ± 2.58	—	—	510 ± 28	—	—	—	—	—	—
	Parietal ctx	0.23 ± 0.08	0.054 ± 0.019	0.099 ± 0.079	0.050 ± 0.023	12.3 ± 3.42	0.30 ± 0.08	2.83 ± 1.02	506 ± 30	11.9	13.6	0.80	13.8^*	10.7	0.87
	Sup. fr. ctx	0.22 ± 0.08	0.057 ± 0.021	0.108 ± 0.083	0.050 ± 0.023	11.7 ± 3.32	0.23 ± 0.08	2.22 ± 0.95	504 ± 26	17.7	19.4	0.79	19.7^*	11.8	0.84
	Hippocampus	0.23 ± 0.07	0.110 ± 0.032	0.178 ± 0.058	0.026 ± 0.008	17.3 ± 5.01	0.82 ± 0.19	7.81 ± 2.73	517 ± 21	10.9	12.9	0.82	12.8^*	5.95	0.90
	Striatum	0.27 ± 0.09	0.066 ± 0.032	0.364 ± 0.133	0.060 ± 0.063	41.4 ± 12.0	3.38 ± 0.72	31.9 ± 10.0	519 ± 31	13.9^*	7.9	0.68	15.8^†	7.82	0.81
SRTM	Cerebellum	—	0.016 ± 0.012	—	—	—	—	—	—	—	—	—	—	—	—
	Parietal ctx	—	0.069 ± 0.011	—	—	—	0.36 ± 0.06	—	449 ± 25	5.73	13.6	0.77	—	—	—
	Sup. fr. ctx	—	0.067 ± 0.008	—	—	—	0.30 ± 0.07	—	467 ± 20	6.60	12.6	0.84	—	—	—
	Hippocampus	—	0.037 ± 0.005	—	—	—	0.70 ± 0.13	—	517 ± 14	4.00	9.92	0.88	—	—	—
	Striatum	—	0.054 ± 0.004	—	—	—	2.21 ± 0.21	—	496 ± 28	3.74	6.06	0.76	—	—	—

↵* P < 0.05.
↵† P < 0.01 (paired Student t test between first and second scans).
Diff = difference; TC = tissue compartment; sup. fr. = superior frontal; ctx = cortex.
Minimum Akaike information criterion indicates more statistically appropriate model. Relative test–retest difference is Δ% = 2 × (scan 2 − scan 1)/(scan 1 + scan 2) × 100%. Average test–retest difference is SD of Δ%. Data are either mean ± SD or individual values.