RT Journal Article
SR Electronic
T1 Cerebral Glucose Metabolic Features of Parkinson Disease and Incident Dementia: Longitudinal Study
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 848
OP 855
DO 10.2967/jnumed.111.089946
VO 52
IS 6
A1 Nicolaas I. Bohnen
A1 Robert A. Koeppe
A1 Satoshi Minoshima
A1 Bruno Giordani
A1 Roger L. Albin
A1 Kirk A. Frey
A1 David E. Kuhl
YR 2011
UL http://jnm.snmjournals.org/content/52/6/848.abstract
AB Longitudinal studies in nondemented Parkinson disease (PD) subjects offer an opportunity to study the earliest regional cerebral subcortical and cortical metabolic changes underlying incident dementia in this disorder. Methods: Twenty-three PD subjects without dementia (Hoehn and Yahr stages I–III; age, 61.8 ± 9.7 y; Mini-Mental State Examination, 28.0 ± 1.4) and 27 controls (age, 59.8 ± 11.5 y) underwent 18F-FDG PET at study entry. PD subjects underwent yearly clinical assessment to determine conversion to dementia. The mean duration of follow-up was 3.9 ± 1.2 y (range, 2.0–6.8 y). Follow-up 18F-FDG PET was available in a subset of subjects at 2 or more years. Both volume-of-interest and 3-dimensional stereotactic surface projection (3D-SSP) analyses were performed. Results: Six subjects became demented (PDD), with a mean time of 3.8 ± 1.7 y (range, 1.9–6.0 y) to development of dementia. Mean duration of disease before onset of dementia was 9.7 ± 4.2 y (range, 3.1–14 y). There were significant metabolic reductions in the occipital (−11.8% vs. controls, F(2,22) = 7.0, P = 0.002) and posterior cingulate (−12.1% vs. controls, F(2,22) = 5.2, P = 0.009) cortices in PDD subjects at baseline, before diagnosis of dementia, compared with controls. Metabolism was most diminished in the visual association cortex (Brodmann area [BA] 18; −20.0% vs. control, F(2,22) = 8.45, P = 0.0007) of PDD subjects. There was mild hypometabolism in the caudate nucleus (−8.4% vs. control, F(2,22) = 3.2, P < 0.05). There was no significant hypometabolism in the temporal or frontal lobes. PD subjects who did not become demented (non-PDD), compared with controls, had reduced cerebral metabolism in the primary occipital cortex (BA 17) that was revealed only by 3D-SSP analysis. Follow-up scans in 5 PDD subjects at 2 y after study entry demonstrated a significant interval within-subject change in the thalamus (−11.4%), posterior cingulate (−9%), occipital (−7%), parietal (−7%), and frontal cortices (−7%) and mild reductions in the temporal cortex (−5%) and hippocampus (−3%), compared with study entry scans. Conclusion: Incident dementia in idiopathic PD is heralded by decreased metabolism in the visual association (BA 18) and posterior cingulate cortices, with mild involvement also of the caudate nucleus. Two-year follow-up data from 5 PDD converters show that progression to dementia is associated with mixed subcortical and cortical changes that involve the mesiofrontal lobes also. These findings provide insights into early metabolic features of parkinsonian dementia.