Purpose: This study aims to determine a lumped constant (LC) value that can be applied to the 2-deoxy-2[18F]fluoro-D-glucose positron emission tomography (FDG-PET) study to yield a physiological value of cerebral metabolic rate of glucose (CMR(glc)) in normal brain.
Procedures: We developed a more robust method for determining the global FDG LC. Dynamic FDG and H(2)(15)O PET studied were acquired in 18 normal subjects. Arterial-venous difference of blood glucose level was measured.
Results: A global LC of 0.65 +/- 0.15 was obtained if a 3-microparameter FDG model (k*(4)=0)was assumed. Assumption of a 4-microparameter FDG model (k*(4) not equal 0) in analyzing the FDG data resulted in a higher LC value of 0.81 +/- 0.18.
Conclusion: The value of LC used for quantitating CMR(glc) should match the assumption inherent to the method of data analysis. The LC results in this study agree well with recent findings in the literature.