RT Journal Article
SR Electronic
T1 Sequential H<sub>2</sub><sup>15</sup>O PET Studies in Baboons: Before and After Amphetamine
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1090
OP 1100
VO 43
IS 8
A1 Julie C. Price
A1 Wayne C. Drevets
A1 James Ruszkiewicz
A1 Phil J. Greer
A1 Victor L. Villemagne
A1 Lei Xu
A1 Sati Mazumdar
A1 Michael N. Cantwell
A1 Chester A. Mathis
YR 2002
UL http://jnm.snmjournals.org/content/43/8/1090.abstract
AB PET and 11C-raclopride have been used to assess dopamine activity in vivo using a paradigm that involved d-amphetamine (AMPH)-induced endogenous dopamine release that led to reductions (relative to baseline) in the 11C-raclopride-specific binding parameter (binding potential). A common assumption in bolus injection PET studies of this type is that cerebral blood flow (CBF) does not vary during the scan. The goal of this work was to examine the effect of AMPH administration on sequential PET measures of CBF. Methods: Eight dynamic H215O PET scans were acquired with arterial blood sampling in 6 baboons: 4 scans before AMPH (over 60 min) and 4 scans after AMPH (over 60 min) (0.6 mg/kg AMPH). Magnetic resonance images (coregistered to PET) were used to define regions of interest that included cortex, striatum (including subregions), and cerebellum. Data were analyzed using a 1-tissue compartment model. CBF was assessed through K1 (mL/mL/min). Results: Temporal patterns of the CBF alterations were similar across regions for each baboon. For 5 of 6 baboons, a general pattern of an initial increase in K1 was observed after AMPH that gradually declined toward baseline, after minimizing anesthesia-induced variability in the in vivo measures. Although these alterations after AMPH were statistically significant in particular subcortical regions and cerebellum, such changes would not likely influence measures of 11C-raclopride binding potential to a significant extent. Conclusion: These data support previous PET studies for which constant blood flow was assumed during the bolus PET 11C-raclopride/AMPH experiment across striatal subregions, while underscoring the importance of considering effects of anesthesia when interpreting in vivo imaging parameters.