QUANTITATIVE BRAIN FDG PET STUDIES USING DYNAMIC AORTIC IMAGING

Positron emission tomography (PET) measurements of cerebral glucose ut ilization using F-18-fluorodeoxyglucose (FDG) are a useful tool in the investigation of localized brain function in normal and disease state s. A major impediment to the application of FDG/PET in clinical invest igation has been the need for arterial blood sampling to quantify cere bral glucose metabolism (CMRGlc). Qualitative studies, though informat ive in a variety of clinical settings, are of limited value for resear ch applications and do not utilize the inherent quantitative nature of PET. We present a novel PET technique employing a whole-body PET tomo graph with abdominal aortic imaging from 0 to 30 min as an alternative to arterial blood sampling to obtain the input function for cerebral metabolic rate calculations. Two or three arterial samples taken durin g the 10-45 min period were used to scale and extend the blood curve a nd the brain was imaged from 35-55 min post-injection. We performed 12 studies in which both arterial blood sampling and aortic scans were o btained. We found the correlation of global metabolic rates (GMR) when comparing the two techniques to be extremely high (R(2) = 0.99). This suggests that the use of dynamic aortic imaging is less invasive and a viable alternative to arterial blood sampling in quantitative FDG/PE T imaging.