Cerebral metabolic patterns at early stages of frontotemporal dementia and semantic dementia. A PET study.
OBJECTIVE
To determine the patterns of cerebral glucose metabolism in frontotemporal dementia (FTD) and semantic dementia (SD).


METHODS
25 patients with mild FTD and 9 patients with mild SD as well as 15 healthy age-matched control subjects underwent 18F-FDG- positron emission tomography. Patient scans were compared with control scans using SPM-99.


RESULTS
As compared with healthy control subjects patients with FTD showed an extensive symmetrical hypometabolism of the frontal lobes (height threshold P <0.01) which spared the motor cortex. Patients with SD showed a hypometabolism in the whole left temporal lobe and in the right temporal pole.


CONCLUSIONS
In the clinical syndromes of FTD and SD two distinct patterns of cerebral metabolism were identified. FTD was associated with frontal hypometabolism, whereas in SD cerebral glucose metabolism was exclusively reduced in the temporal lobes. Our findings are consistent with the notion that FTD and SD begin as strictly lobar neuronal degenerations and that a spread of pathological changes is not seen until more advanced stages.
Diehl
J
J
Department of Psychiatry, Technische Universität München, Munich, Germany. jaime.diehl@lrz.tu-muenchen.de
Grimmer
T
T
Drzezga
A
A
Riemenschneider
M
M
Förstl
H
H
Kurz
A
A
D000368:Aged; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D003704:Dementia / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D018450:Disease Progression; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D011237:Predictive Value of Tests; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D014055:Tomography, Emission-Computed
D005947:Glucose