Abstract
BackgroundPrevious studies have shown different clinical and imaging pattern in tremordominant and akinetic-rigid Parkinson’s disease (PD) subtypes. The association between dopaminergic and glucose metabolism has in contrast not been investigated yet. Therefore, this study compared PD subtypes with respect to clinical and imaging findings with the aim of establishing a relationship between clinical subtypes, dopamine and glucose metabolism.MethodsTwo groups of a total of 64 idiopathic PD patients (42 male, 22 female, mean age 56±10.9 years) were analysed: akinetic-rigid (AR, n = 32) and tremor-dominant (TD, n = 32) patients. Both were compared with respect to differential involvement of local striatal dopamine and glucose metabolism using [18F]-fluoro-L-dopa (F-dopa) and [18F]-fluorodeoxyglucose (FDG)-PET.ResultsThe analysis of PD subgroups showed significant differences in the F-dopa uptake in the anterior putamen. Using the results of the local striatal dopamine difference as a volume of interest for the FDG-analysis, analysis of AR patients revealed a significantly lower normalised cerebral metabolic rate of glucose (nCMRGlc) within the ventral striatum.ConclusionsThe dual tracer study illlustrates clear differences between TD and AR subtypes in the ventral striatum. In accordance with previous FP-CIT-SPECT studies, it discloses congruent results for the presynaptic dopaminergic system and extends the knowledge about an additional involvement of local metabolic activity in the caudate and anterior putamen. The findings corroborate the specific role of distinct PD subtypes within the cerebello-thalamo-cortical-circuits. Multitracer PET imaging may thus enhance the knowledge about the clinical segregation into subtypes.
Highlights
Parkinson’s disease (PD) patients differ concerning the clinical progress, symptom severity and symptom onset [1,2,3]
Rosenberg-Katz and coworkers demonstrated a gray matter atrophy in motor-related regions in postural-instability gait difficulty (PIGD) subtypes [5], which can be seen as a counterpart of akinetic-rigid patients, whereas white matter hyperintensities could not be assigned to one PD subtype [6]
Patients were matched as one aim of this study was to present different pathophysiologic aspects of PD subtypes
Summary
Parkinson’s disease (PD) patients differ concerning the clinical progress, symptom severity and symptom onset [1,2,3]. The wellknown subtyping into akinetic-rigid, tremordominant and equivalent subtypes was recently amended by four large clusters of symptoms, e.g. patients with the main cluster profiles ‘‘old age-atonset and rapid disease progression’’ and ‘‘young age-at-onset and slow disease progression’’ [4]. These results of PD subtyping have, not been transferred into clinical routine and large prospective cohorts confirming these data sets are pending. Previous studies have shown different clinical and imaging pattern in tremordominant and akinetic-rigid Parkinson’s disease (PD) subtypes. This study compared PD subtypes with respect to clinical and imaging findings with the aim of establishing a relationship between clinical subtypes, dopamine and glucose metabolism
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