title: Differential effects of global and cerebellar normalization on detection and differentiation of dementia in FDG-PET studies.
abstract: 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.
authors.affiliation: Max-Planck-Institute for Human Cognitive and Brain Sciences, Stephanstr. 1A 04103 Leipzig, Germany. dukart@cbs.mpg.de
authors.forename: Juergen
authors.initials: J
authors.lastname: Dukart
authors.forename: Karsten
authors.initials: K
authors.lastname: Mueller
authors.forename: Annette
authors.initials: A
authors.lastname: Horstmann
authors.forename: Barbara
authors.initials: B
authors.lastname: Vogt
authors.forename: Stefan
authors.initials: S
authors.lastname: Frisch
authors.forename: Henryk
authors.initials: H
authors.lastname: Barthel
authors.forename: Georg
authors.initials: G
authors.lastname: Becker
authors.forename: Harald E
authors.initials: HE
authors.lastname: Möller
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
authors.forename: Osama
authors.initials: O
authors.lastname: Sabri
authors.forename: Matthias L
authors.initials: ML
authors.lastname: Schroeter
mesh_terms: 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
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose