THESES

Parkinson's disease: the role of dopamine transporter neuroimaging in clinically unclear cases (Abstract)

Doença de Parkinson: neuroimagem do transportador de dopamina em casos de dúvida diagnóstica (Resumo)

Andre Carvalho Felicio

Tese de doutorado, Universidade Federal de São Paulo – UNIFESP (Área de concentração: Neurologia clínica)

Correspondence

ABSTRACT

INTRODUCTION: Misdiagnosis in Parkinson's disease (PD) can reach 25%. Recently, single-photon emission computer tomography (SPECT), using dopamine transporter (DAT) radioligands, has become useful to help diagnose clinically unclear cases of Parkinsonism (CUCP).
OBJECTIVES: Study 1 reported the rationale of molecular imaging in CUCP. Study 2 evaluated the role of DAT neuroimaging in CUCP. Study 3 studied a sub-group of CUCP with psychogenic Parkinsonism. Study 4 investigated the relationship between DAT and depression in PD.
METHODS: Brain SPECT imaging was undertaken using the DAT radiotracer [^99mTc]-TRODAT-1 at baseline to determine pre-synaptic dopaminergic dysfunction. Patients were followed-up, and a final clinical diagnosis was made.
RESULTS: In study 1, convincing evidence showed that molecular imaging can reduce diagnostic uncertainty in PD. In study 2, disagreement rate between SPECT imaging versus golden standard clinical diagnosis reached 20%. Sensitivity and specificity (DAT scan) were, respectively, 100 and 70%. However, in study 3, two out of five subjects with psychogenic Parkinsonism had DAT densities under the cut-off suggesting a degenerative Parkinsonism. In study 4, DAT density was greater in PD patients with depression.
CONCLUSIONS: This thesis confirmed the useful role of molecular imaging in CUCP, and provided in vivo information about different underlying PD-related physiopathology mechanisms.

Key words: Parkinson's disease, photon emission computer tomography, dopamine transporter, depression.

Correspondence:
Andre Carvalho Felicio
Rua Napoleão de Barros 865
04023-900, São Paulo SP - Brazil
E-mail: cf.andre@gmail.com

Orientador: Professor Doutor Henrique Ballalai Ferraz.
Co-orientador: Professor Doutor Rodrigo Affonseca Bressan.
Support: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).