RT Journal Article SR Electronic T1 Quantification of Task-Specific Glucose Metabolism with Constant Infusion of 18F-FDG JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1933 OP 1940 DO 10.2967/jnumed.116.176156 VO 57 IS 12 A1 Andreas Hahn A1 Gregor Gryglewski A1 Lukas Nics A1 Marius Hienert A1 Lucas Rischka A1 Chrysoula Vraka A1 Helen Sigurdardottir A1 Thomas Vanicek A1 Gregory M. James A1 René Seiger A1 Alexander Kautzky A1 Leo Silberbauer A1 Wolfgang Wadsak A1 Markus Mitterhauser A1 Marcus Hacker A1 Siegfried Kasper A1 Rupert Lanzenberger YR 2016 UL http://jnm.snmjournals.org/content/57/12/1933.abstract AB The investigation of cerebral metabolic rate of glucose (CMRGlu) at baseline and during specific tasks previously required separate scans with the drawback of high intrasubject variability. We aimed to validate a novel approach to assessing baseline glucose metabolism and task-specific changes in a single measurement with a constant infusion of 18F-FDG. Methods: Fifteen healthy subjects underwent two PET measurements with arterial blood sampling. As a reference, baseline CMRGlu was quantified from a 60-min scan after 18F-FDG bolus application using the Patlak plot (eyes closed). For the other scan, a constant radioligand infusion was applied for 95 min, during which the subjects opened their eyes at 10–20 min and 60–70 min and tapped their right thumb to their fingers at 35–45 min and 85–95 min. The constant-infusion scan was quantified in two steps. First, the general linear model was used to fit regional time–activity curves with regressors for baseline metabolism, task-specific changes for the eyes-open and finger-tapping conditions, and movement parameters. Second, the Patlak plot was used for quantification of CMRGlu. Multiplication of the baseline regressor by β-values from the general linear model yielded regionally specific time–activity curves for baseline metabolism. Further, task-specific changes in metabolism are directly proportional to changes in the slope of the time–activity curve and hence to changes in CMRGlu. Results: Baseline CMRGlu from the constant-infusion scan matched that from the bolus application (test–retest variability, 1.1% ± 24.7%), which was not the case for a previously suggested approach (variability, −39.9% ± 25.2%, P < 0.001). Task-specific CMRGlu increased in the primary visual and motor cortices for eyes open and finger tapping, respectively (P < 0.05, familywise error–corrected), with absolute changes of up to 2.1 μmol/100 g/min and 6.3% relative to baseline. For eyes open, a decreased CMRGlu was observed in default-mode regions (P < 0.05, familywise error–corrected). CMRGlu quantified with venous blood samples (n = 6) showed excellent agreement with results obtained from arterial samples (r > 0.99). Conclusion: Baseline glucose metabolism and task-specific changes can be quantified in a single measurement with constant infusion of 18F-FDG and venous blood sampling. The high sensitivity and regional specificity of the approach offer novel possibilities for functional and multimodal brain imaging.