title: Imaging beyond the striatonigral dopaminergic system in Parkinson's disease.
abstract: Parkinson 's disease (PD) is characterized by progressive loss of dopaminergic  neurons in the nigrostriatal pathway, but this seems to constitute only part of the whole  pathological process of the disease. Accumulating data have documented the concomitant  degeneration of other dopaminergic pathways and of the serotonergic, cholinergic and  noradrenergic neurotransmitter systems. In addition, pathologic process is not only  restricted in the brain, since the spinal cord and the peripheral autonomic nervous system  are also affected. The pathogenesis of PD remains unclear. The use of positron emission  tomography and single photon emission tomography may contribute to the understanding  of these aspects of the disease. This review will discuss the role of PET and SPET in imaging  the extrastriatal dopaminergic system and other neurotransmitter systems as well as the imaging  of microglial activation and cardiac sympathetic denervation in PD.  In conclusion, several PET and SPET ligands can detect changes in extrastriatal dopaminergic  system as well as in the serotonergic, cholinergic and noradrenergic systems in PD and also explore  its possible correlation with motor and non motor symptoms. The use of PET scintigraphy allows the  detection of microglial activation in PD, while (123)I-MIBG scintigraphy depicts cardiac sympathetic  denervation in PD and is a useful imaging tool for differentiating PD from other types of parkinsonism.
authors.affiliation: Third University Department of Neurology, Aristotle University of Thessaloniki, Thessaloniki, Makedonia, Greece.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Giza
authors.forename: Anna
authors.initials: A
authors.lastname: Gotzamani-Psarrakou
authors.forename: Sevasti
authors.initials: S
authors.lastname: Bostantjopoulou
mesh_terms: D003342:Corpus Striatum / Q000000981:diagnostic imaging*; D059290:Dopaminergic Neurons / Q000000981:diagnostic imaging*; D006801:Humans; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D013378:Substantia Nigra / Q000000981:diagnostic imaging*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*