Molecular imaging studies in Parkinson disease: reducing diagnostic uncertainty.
BACKGROUND
The diagnosis of Parkinson disease (PD) is based on clinical criteria but misdiagnosis is as high as 25% of cases as confirmed by anatomic-pathologic studies. Since the introduction of in vivo molecular imaging techniques using Single-Photon Emission Computed Tomography and Positron Emission Tomography, the diagnosis of PD became more reliable by assessing dopaminergic and even nondopaminergic systems.


RESULTS
The purpose of this article is to critically review the current data on molecular neuroimaging focusing on the nigrostriatal circuitry and providing useful information on the role of these new imaging techniques in the management of clinically unclear cases of PD.


CONCLUSIONS
Patients with essential tremor, psychogenic Parkinsonism or drug-induced Parkinsonism can be differentiated from PD in doubtful situations using molecular imaging techniques evaluating striatal dopamine transporters (DAT). However, in patients with vascular Parkinsonism, atypical Parkinsonism and Parkinsonism associated with dementia DAT scans have less diagnostic usefulness. Scans with non-DAT tracers (ie, D2 dopamine receptors) are necessary together with long-term clinical follow-up, and rescans to improve diagnostic accuracy.
Felicio
Andre C
AC
Department of Neurology and Neurosurgery, Movement Disorders Unit, Universidade Federal de Sao Paulo, Sao Paulo, Brazil. cf.andre@gmail.com
Shih
Ming C
MC
Godeiro-Junior
Clecio
C
Andrade
Luiz A F
LA
Bressan
Rodrigo A
RA
Ferraz
Henrique B
HB
D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism; D003704:Dementia / Q000175:diagnosis / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D004296:Dopa Decarboxylase / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D020329:Essential Tremor / Q000175:diagnosis / Q000000981:diagnostic imaging; D006801:Humans; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000175:diagnosis / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D011868:Radioisotopes; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism
D050483:Dopamine Plasma Membrane Transport Proteins; D011868:Radioisotopes; D017448:Receptors, Dopamine D2; D050493:Vesicular Monoamine Transport Proteins; D004296:Dopa Decarboxylase