Table 1.

Correlation coefficients for the area-under-the-curve of the plasma time-activity curve (AUC) using the concentrations of [¹¹C](R)-rolipram measured at two time points

		Time of first plasma concentration (min)
		1.5	3	4	6	8	10	15	20	30	40	50	60	75	90
Time of second plasma concentration (min)	1.5	−0.022	0.117	0.097	0.079	0.071	0.065	0.058	0.057	0.060	0.063	0.065	0.065	0.063	0.060
	3		0.677	0.738	0.760	0.768	0.774	0.790	0.807	0.833	0.849	0.856	0.859	0.858	0.853
	4			0.796	0.826	0.843	0.855	0.877	0.894	0.919	0.933	0.942	0.947	0.950	0.950
	6				0.855	0.871	0.881	0.900	0.919	0.947	0.963	0.973	0.978	0.981	0.981
	8					0.883	0.889	0.903	0.921	0.955	0.975	0.985	0.990	0.991	0.990
	10						0.891	0.900	0.917	0.954	0.976	0.987	0.991	0.991	0.988
	15							0.900	0.914	0.949	0.970	0.981	0.985	0.984	0.980
	20								0.924	0.952	0.969	0.977	0.980	0.979	0.976
	30									0.963	0.968	0.970	0.969	0.968	0.965
	40										0.965	0.961	0.957	0.953	0.950
	50											0.953	0.947	0.941	0.937
	60												0.939	0.931	0.925
	75													0.920	0.912
	90														0.903

The values along the diagonal (in italics) use only one sample and represent the correlation coefficients between the activities of individual time points with the AUCs. Values above the diagonal represent the correlation coefficients between the AUC and the mean activities of pairs of individual samples. The value at 1.5 minutes is the peak value. The highest (best) correlation was obtained using blood samples at 10 and 75 min.