11C-PIB PET imaging in Alzheimer disease and frontotemporal lobar degeneration.
BACKGROUND
The PET tracer (11)C-labeled Pittsburgh Compound-B ((11)C-PIB) specifically binds fibrillar amyloid-beta (Abeta) plaques and can be detected in Alzheimer disease (AD). We hypothesized that PET imaging with (11)C-PIB would discriminate AD from frontotemporal lobar degeneration (FTLD), a non-Abeta dementia.


METHODS
Patients meeting research criteria for AD (n = 7) or FTLD (n = 12) and cognitively normal controls (n = 8) underwent PET imaging with (11)C-PIB (patients and controls) and (18)F-fluorodeoxyglucose ((18)F-FDG) (patients only). (11)C-PIB whole brain and region of interest (ROI) distribution volume ratios (DVR) were calculated using Logan graphical analysis with cerebellum as a reference region. DVR images were visually rated by a blinded investigator as positive or negative for cortical (11)C-PIB, and summed (18)F-FDG images were rated as consistent with AD or FTLD.


RESULTS
All patients with AD (7/7) had positive (11)C-PIB scans by visual inspection, while 8/12 patients with FTLD and 7/8 controls had negative scans. Of the four PIB-positive patients with FTLD, two had (18)F-FDG scans that suggested AD, and two had (18)F-FDG scans suggestive of FTLD. Mean DVRs were higher in AD than in FTLD in whole brain, lateral frontal, precuneus, and lateral temporal cortex (p < 0.05), while DVRs in FTLD did not significantly differ from controls.


CONCLUSIONS
PET imaging with (11)C-labeled Pittsburgh Compound-B ((11)C-PIB) helps discriminate Alzheimer disease (AD) from frontotemporal lobar degeneration (FTLD). Pathologic correlation is needed to determine whether patients with PIB-positive FTLD represent false positives, comorbid FTLD/AD pathology, or AD pathology mimicking an FTLD clinical syndrome.
Rabinovici
G D
GD
Memory &Aging Center, University of California San Fransisco, San Francisco, CA 94117, USA. grabinovici@memory.ucsf.edu
Furst
A J
AJ
O'Neil
J P
JP
Racine
C A
CA
Mormino
E C
EC
Baker
S L
SL
Chetty
S
S
Patel
P
P
Pagliaro
T A
TA
Klunk
W E
WE
Mathis
C A
CA
Rosen
H J
HJ
Miller
B L
BL
Jagust
W J
WJ
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D000814:Aniline Compounds; D052160:Benzothiazoles; D001921:Brain / Q000000981:diagnostic imaging*; D003704:Dementia / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013844:Thiazoles
C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D000814:Aniline Compounds; D052160:Benzothiazoles; D019275:Radiopharmaceuticals; D013844:Thiazoles