Current status and future challenges of brain imaging with 18F-DOPA PET for movement disorders

Objective: Parkinson's disease (PD) is a neurodegenerative disorder (ND) due to progressive loss of dopaminergic neurons in the basal ganglia. The correct differential diagnosis of this disease with parkinsonian syndromes (PS) or with essential tremor (ET) is a diagnostic dilemma, considering that only PD is responsive to treatment with levodopa. Traditional imaging fails to diagnose PD because morphological alterations in the brain are usually detectable only at advanced stages. Single photon emission tomography (SPET) with cocaine analogues has recently been used in the early detection of PD. The fluoro-18-deoxyphenyl-alanine (F-18-DOPA) is a positron emission tomography (PET) tracer with selective in vivo affinity to the basal ganglia, due to the specific metabolism of substantia nigra. We assessed the effective use of F-18-DOPA PET in brain imaging in order to describe the function of presynaptic disorders of PD, PS, ET and other movement disorders compared to SPET imaging and also discussed novel radiopharmaceuticals. The role of magnetic resonance imaging (MRI) was also discussed. Conclusion: The F-18-DOPA PET imaging is still the best diagnostic tool for the diagnosis of PD and other movement disorders. Fluorine-18-FDG PET can play a role in the differential diagnosis between PD and other PS. The hybrid F-18-DOPA PET/MRI seems to be able to play an important additional role in early diagnosis of the above syndromes.