Single time point quantitation of cerebral glucose metabolism by FDG-PET without arterial sampling

Cumming, Paul; Dias, André H.; Gormsen, Lars C.; Hansen, Allan K.; Alberts, Ian; Rominger, Axel; Munk, Ole L.; Sari, Hasan

doi:10.1186/s13550-023-01049-3

EJNMMI Research

Table 2 Population based results from the pharmacokinetic analysis of FDG in arterial blood and (n=24) patients from Bern

From: Single time point quantitation of cerebral glucose metabolism by FDG-PET without arterial sampling

	Aarhus (n = 52)	Bern (n = 24)
AUC_(0–67), measured	100.0 ± 13.1	100.0 ± 12.3
Ce^−λ3(t) (Method 1)	84.7 ± 3.9	83.6 ± 2.5
Be^−λ2(t) + Ce^−λ3(t)	95.5 ± 2.1	94.5 ± 1.6
Ae^−λ1(t) + Be^−λ2(t) + Ce^−λ3(t)	98.7 ± 2.4	97.8 ± 2.1
Age (years)	56.5 ± 14.1	59.7 ± 15.2
λ3 (min⁻¹)	0.0121 ± 0.0026	0.0094 ± 0.0019
theta_{(52–67 min)} (min)	111.3 ± 9.8	100.8 ± 6.7
λ3 (min⁻¹) versus age (years) (see Fig. 1C)	λ3 = − 0.0000936*(age) + 0.0174 (r = − 0.514; p > 0.0001)	λ3 = 0(age) + 0.00946 (r = − 0.011; not significant)
AUC_{(0–67 min)} versus Ca_(52–67) (see Fig. 1D, Method 2)	AUC_{(0–67 min)} = 63.2*(Ca_{(52–67 min)}) + 374 (r = + 0.678; p < 0.00001)	AUC_{(0–67 min)} = 104.0(Ca_(52–67)) + 2.9 (r = + 0.885; p < 0.00001
theta_{(52–67 min)} (min) versus λ3 (min⁻¹) (see Fig. 1E, Method 3)	theta_{(52–67 min)} = 2953*(λ3) + 75.57 (r = + 0.796; p < 0.00001)	theta_{(52–67 min)} = 2971(λ3) + 72.89 (r = + 0.846; p < 0.00001)
theta_{(52–67 min)} (min) versus age (years) (see Fig. 1F, Method 4)	theta_{(52–67 min)} = − 0.313*(age) + 129 (r = − 0.46; p < 0.0002)	theta_{(52–67 min)} = 0.0477(age) + 98.0 (r = + 0.17, n.s.)

We obtained population-based results from the pharmacokinetics of FDG in arterial blood measured during PET recordings lasting 67 min, based on observations in (n = 52) patients from Aarhus and (n = 24) patients in Bern. The total measured AUC_(0–67) was calculated from the IDIF measured during the complete dynamic recordings, and normalized to a mean of 100 arbitrary units of concentration-min. This AUC_(0–67) is shown along with the percentage AUC recoveries from (1) the final phase of the tri-exponential function (ACe^−λ3(t)), (2) the sum of the intermediate and final phases (Be^−λ2(t) + Ce^−λ3(t)), and (3) the complete tri-exponential function (Ae^−λ1(t) + Be^−λ2(t) + Ce^−λ3(t)). We also report some relationships discovered for one or both sites, i.e., (1) the magnitude of λ3, which corresponds to renal clearance of FDG, versus subject age, (2) theta_{(55–67 min)} versus λ3, AUC_{(0–67 min)} versus Ca_{(52–67 min)}, and theta_{(52–67 min)} versus subject age. Methods 1,2,3, and 4 refer to the specified empirical relationships for estimating the magnitude of FDG-K_i in brain from a two-point Patlak linear graphic analysis defined by (1) the population mean gray matter V_D (0.55 ml g⁻¹) and (2) estimations of AUC_{(0–67 min)}/ theta_{(52–67 min)} obtained from late phase recordings. In Method 1, we estimated the AUC_(0–67) from the individual Ce^−λ3(t)scaled by the population mean percentage AUC recoveries (84.7% in Aarhus, 83.6% in Bern). In Method 2, we estimated AUC_(0–67) and thence theta_{(52–67 min)} from the individual Ca_{(52–67 min)} and the site-dependent empirical relationship. In Method 3, we estimated theta_{(52–67 min)} from the individual λ3 based on the final 30 min of the recording and the site-dependent empirical relationship. In Method 4, we estimated theta_{(52–67 min)} from the individual subject age and the site-dependent empirical relationship

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