Detection of Alzheimer pathology in vivo using both 11C-PIB and 18F-FDDNP PET.
11C-Pittsburgh Compound-B (11C-PIB) and 18F-(2-(1-{6-[(2-[18F]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene) (18F-FDDNP) have been developed as PET tracers for in vivo imaging of pathology in Alzheimer's disease (AD). The purpose of this study was to directly compare these tracers in patients with AD, patients with mild cognitive impairment (MCI), and healthy controls.


METHODS
Paired 11C-PIB and 18F-FDDNP scans were acquired in 14 patients with AD, 11 patients with amnestic MCI, and 13 controls. For both tracers, parametric images of binding potential (BPND) were generated. Global cortical BPND was assessed using ANOVA. In addition, regional patterns of BPND were compared between diagnostic groups using ANOVA for repeated measures.


RESULTS
Global cortical BPND of 11C-PIB showed higher binding in patients with AD than in controls and patients with MCI. 18F-FDDNP uptake was higher in patients with AD than in controls, but MCI could not be distinguished from AD or from controls. Global BPND values of both tracers were moderately correlated (r=0.45; P=0.005). In MCI, BPND of 11C-PIB showed a bimodal distribution, whereas values for 18F-FDDNP were more widespread, with more MCI patients demonstrating increased uptake. Regional 11C-PIB binding showed different patterns across diagnostic groups, as AD patients showed an overall increase in binding, with the lowest binding in the medial temporal lobe. With 18F-FDDNP, patterns were similar across diagnostic groups. For all groups, highest values were observed in the medial temporal lobe.


CONCLUSIONS
Differences in BPND between patients with AD, patients with MCI, and controls were more pronounced for 11C-PIB. The difference in regional binding, the moderate correlation, and the discrepant findings in MCI suggest that they measure related, but different, characteristics of the disease.
Tolboom
Nelleke
N
Department of Nuclear Medicine and PET Research, VU University Medical Centre, Amsterdam, The Netherlands. n.tolboom@vumc.nl
Yaqub
Maqsood
M
van der Flier
Wiesje M
WM
Boellaard
Ronald
R
Luurtsema
Gert
G
Windhorst
Albert D
AD
Barkhof
Frederik
F
Scheltens
Philip
P
Lammertsma
Adriaan A
AA
van Berckel
Bart N M
BN
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D000814:Aniline Compounds; D052160:Benzothiazoles; D002250:Carbon Radioisotopes; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000473:pathology; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005462:Fluorine Radioisotopes; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009570:Nitriles; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013844:Thiazoles
C444520:2-(1-(6-((2-fluoroethyl)(methyl)amino)-2-naphthyl)ethylidene)malononitrile; C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D000814:Aniline Compounds; D052160:Benzothiazoles; D002250:Carbon Radioisotopes; D005462:Fluorine Radioisotopes; D009570:Nitriles; D019275:Radiopharmaceuticals; D013844:Thiazoles