An FP-CIT PET comparison of the difference in dopaminergic neuronal loss in subtypes of early Parkinson's disease.
BACKGROUND
Patients with tremor-dominant Parkinson's disease (PD) have slower disease progression, show less cognitive decline, and have more favorable outcomes than patients with non-tremor PD. However, the pathophysiology of PD tremor remains unclear. Whether there are differences in nigrostriatal dopaminergic dysfunction between the two PD subtypes is unknown.


OBJECTIVE
To evaluate the differences in regional dopamine transporter (DAT) density in the brain between different subtypes of early PD using FP-CIT PET/CT.


METHODS
We recruited 43 patients with PD (21 tremor-dominant PD [TP] and 22 non-tremor-dominant PD [NTP]) and 18 age-matched healthy controls. All patients with PD underwent FP-CIT PET/CT imaging and evaluated Parkinsonian motor severity by using the Hoehn and Yahr stage and Part III of the Unified Parkinson's Disease Rating Scale (UPDRS). We also compared tremor and non-tremor symptoms with motor phenotype scores between two subtypes of PD.


RESULTS
All patients with PD demonstrated a significantly decreased FP-CIT uptake in the putamen compared to healthy controls. Differences in putamen FP-CIT uptake versus caudate nucleus FP-CIT uptake in PD showed putamen uptake was significantly more impaired than that in the caudate nucleus. However, there was no significant difference in FP-CIT uptake in the striatum between both PD groups at the same early stage of disease.


CONCLUSIONS
We suggest that differential of DAT uptake in the striatum did not allow for a reliable separation of subtypes into tremor-dominant and non-tremor-dominant, especially in the early stages of PD. Therefore, we assumed that many systems besides the nigrostriatal dopaminergic system are involved in the generation of tremors in PD.
Department of Neurology, College of Medicine, The Catholic University of Korea, Incheon, Republic of Korea.
In-Uk
IU
Song
Yong-An
YA
Chung
Jin-Kyoung
JK
Oh
Sung-Woo
SW
Chung
D000368:Aged; D016022:Case-Control Studies; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D064847:Multimodal Imaging; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D010641:Phenotype; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed
D050483:Dopamine Plasma Membrane Transport Proteins
FP-CIT PET; Parkinson’s disease; nigrostriatal dopaminergic system; tremor