Abstract
602
Objectives Any tracer in fetal tissue comes from maternal arterial blood. Provided steady state is achieved and intermediate compartments are reversible, the same graphical methods of analysis applied to adult rhesus monkey data can also be used in assessing those same parameters in the fetus. This work demonstrates the use of conventional Logan graphical analysis methods in assessing fetal dopaminergic receptor characteristics using [18F]-fallypride.
Methods Two pregnant rhesus macaques were imaged over 150 minutes with [18F]-fallypride on a GE Discovery LS PET/CT scanner. Animals were oriented perpendicularly to the scanner bed in a left lateral decubitus position, enabling dynamic imaging of the fetus and all maternal organs in a single bed position. Distribution volumes (DVs) were assessed for the maternal and fetal striatum using the metabolite corrected left ventricular chamber of the maternal heart. DVRs were also assessed for maternal and fetal striatum using each respective cerebellum and again for the fetal striatum using the maternal cerebellum.
Results Mean DVR results for maternal striatum are 28.8 +/- 3.7 and are consistent with literature values. Mean DVR results for fetal striatum are 14.0 +/- 2.8, 12.8 +/- 3.4, and 13.8 +/- 2.1 using maternal arterial plasma, maternal cerebellum, and fetal cerebellum respectively. The agreement between all fetal striatal DVRs using varying input parameters demonstrates that the conditions necessary for conventional graphical analysis have been met.
Conclusions We have demonstrated a non-invasive in-utero analysis method capable of delivering the same primary outcome measurements typically associated with reversible tracers in PET brain imaging.
- © 2009 by Society of Nuclear Medicine