Fig 1.
[18F]AB5186 radiosynthesis.
Fig 2.
Distribution and kinetics of [18F]AB5186 in rats.
(a) Representative PET sum images of [18F]AB5186 at different times points showing distribution of novel radiotracer in rat brain and (b) heart and lungs. PET images co-registered with CT images. Average SUV TACs in brain, heart, lungs and blood pool (c), as well as, different brain regions (d) following bolus intravenous injection of [18F]AB5186. Note reversible tissue kinetics of novel TSPO PET radiotracer. Data presented as mean±SEM, n = 3.
Fig 3.
Concentration of [18F]AB5186 and parent fraction in rat whole blood and plasma.
Normalised measured radioactive concentration in whole blood and plasma using different sampling methods (a) and parent fraction profile in plasma over time following bolus intravenous injection of [18F]AB5186. The insert graph shows the same data between 0–10 minutes. (b). Automatic whole blood and plasma refer to measurements using the automatic blood sampler system. Manual whole blood and plasma refer to measurements using manual sampling of arterial blood. All data has been normalized relative to injected dose, so that the different whole blood and plasma curves can be compared with each other. Data presented as mean±SEM, n = 3.
Fig 4.
Comparative analysis between VT obtained using 2T model and Logan graphical analysis with different input functions for all tissues (a) and brain regions only (b). Note strong correlation despite bias of manual sampling and image derived input functions relative to automatic blood sampler. IDIF, image derived input function.
Fig 5.
Bland-Altman plots assessing agreement between 2T model and Logan graphical analysis in all tissues with different input functions methods.
Group 1 (Logan) and Group 1 (2T) (a); Group 1 (Logan) and Group 2 (Logan) (b); and Group 1 (Logan) and Group 3 (Logan) (c). This was also carried out using only brain regions for Group 1 (Logan) and Group 1 (2T) (d); Group 1 (Logan) and Group 2 (Logan) (e); and Group 1 (Logan) and Group 3 (Logan) (f).
Fig 6.
Calculated typical error of measurement (TEM) and coefficients of variation (COV).
(a) TEM of tissues and (b) brain regions for all methods investigated. (c) %COV of tissues and (d) brain regions for all methods investigated. G1 = group 1 (automatic blood sampling), G2 = group 2 (manual sampling) and G3 = group 3 (image derived input function).
Table 1.
[18F]AB5186 kinetic modelling results obtained using 2T compartmental model and Logan graphical analysis with various methods used to derive the input function (mean±SEM, n = 3).