Simplified quantification of nicotinic receptors with 2[18F]F-A-85380 PET.
BACKGROUND
Neuronal nicotinic acetylcholine receptors (nAChRs), widely distributed in the human brain, are implicated in various neurophysiological processes as well as being particularly affected in neurodegenerative conditions such as Alzheimer's disease. We sought to evaluate a minimally invasive method for quantification of nAChR distribution in the normal human brain, suitable for routine clinical application, using 2[(18)F]F-A-85380 and positron emission tomography (PET).


METHODS
Ten normal volunteers (four females and six males, aged 63.40+/-9.22 years) underwent a dynamic 120-min PET scan after injection of 226 MBq 2[(18)F]F-A-85380 along with arterial blood sampling. Regional binding was assessed through standardized uptake value (SUV) and distribution volumes (DV) obtained using both compartmental (DV(2CM)) and graphical analysis (DV(Logan)). A simplified approach to the estimation of DV (DV(simplified)), defined as the region-to-plasma ratio at apparent steady state (90-120 min post injection), was compared with the other quantification approaches.


RESULTS
DV(Logan) values were higher than DV(2CM). A strong correlation was observed between DV(simplified), DV(Logan) (r=.94) and DV(2CM) (r=.90) in cortical regions, with lower correlations in thalamus (r=.71 and .82, respectively). Standardized uptake value showed low correlation against DV(Logan) and DV(2CM).


CONCLUSIONS
DV(simplified) determined by the ratio of tissue to metabolite-corrected plasma using a single 90- to 120-min PET acquisition appears acceptable for quantification of cortical nAChR binding with 2[(18)F]F-A-85380 and suitable for clinical application.
Mitkovski
Sascha
S
Department of Nuclear Medicine and Centre for PET, Austin Hospital, Victoria 3084, Melbourne, Australia.
Villemagne
Victor L
VL
Novakovic
Kathy E
KE
O'Keefe
Graeme
G
Tochon-Danguy
Henri
H
Mulligan
Rachel S
RS
Dickinson
Kerryn L
KL
Saunder
Tim
T
Gregoire
Marie-Claude
MC
Bottlaender
Michel
M
Dolle
Frederic
F
Rowe
Christopher C
CC
D001384:Azetidines / Q000493:pharmacokinetics; D001800:Blood Specimen Collection; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D001931:Brain Mapping; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011725:Pyridines / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D011978:Receptors, Nicotinic / Q000378:metabolism*; D014018:Tissue Distribution
C119803:2-fluoro-3-(2-azetidinylmethoxy)pyridine; D001384:Azetidines; D005462:Fluorine Radioisotopes; D011725:Pyridines; D019275:Radiopharmaceuticals; D011978:Receptors, Nicotinic