Differential effects of global and cerebellar normalization on detection and differentiation of dementia in FDG-PET studies.
FDG-PET ([18F]fluorodeoxyglucose positron emission tomography) is frequently used to improve the differential diagnosis of dementia. However, a fundamental methodological issue of the reference area for the intensity normalization procedure is still unsolved. Here, we systematically compared the two most commonly used normalization methods to the cerebral and to the cerebellar metabolic rate for glucose with regard to detection and differentiation of dementia syndromes. FDG-PET imaging was performed on 19 subjects with early Alzheimer's disease, 13 subjects with early frontotemporal lobar degeneration and 10 subjects complaining of memory impairment, which had not been confirmed by comprehensive clinical testing. Images were normalized to either the cerebral or the cerebellar metabolic rate for glucose. Differences in relative regional glucose metabolism were assessed by voxelwise comparison. Analysis using the two normalization procedures revealed remarkable differential effects. Whereas cerebellar normalization was superior in identifying dementia patients in comparison to control subjects, cerebral normalization showed better results for differential diagnosis between types of dementia. These effects were shown for both, Alzheimer's disease and frontotemporal lobar degeneration. Relative hypermetabolism in comparison to the control group was only detected in both kinds of dementia using global normalization. The results indicate that normalization has a decisive impact on diagnostic accuracy in dementia. While cerebellar normalization seems to be more sensitive for early diagnosis, cerebral global normalization might be superior for differential diagnostic purposes in dementia syndromes.
Dukart
Juergen
J
Max-Planck-Institute for Human Cognitive and Brain Sciences, Stephanstr. 1A 04103 Leipzig, Germany. dukart@cbs.mpg.de
Mueller
Karsten
K
Horstmann
Annette
A
Vogt
Barbara
B
Frisch
Stefan
S
Barthel
Henryk
H
Becker
Georg
G
Möller
Harald E
HE
Villringer
Arno
A
Sabri
Osama
O
Schroeter
Matthias L
ML
D000367:Age Factors; D000544:Alzheimer Disease / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism; D000704:Analysis of Variance; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D001931:Brain Mapping / Q000379:methods; D002531:Cerebellum / Q000000981:diagnostic imaging* / Q000378:metabolism; D003704:Dementia / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D057174:Frontotemporal Lobar Degeneration / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012720:Severity of Illness Index; D012815:Signal Processing, Computer-Assisted
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose