Molecular imaging studies in Parkinson disease: reducing diagnostic uncertainty

Neurologist. 2009 Jan;15(1):6-16. doi: 10.1097/NRL.0b013e318183fdd8.


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.

Review summary: 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Brain / diagnostic imaging
  • Brain / metabolism
  • Corpus Striatum / diagnostic imaging
  • Corpus Striatum / metabolism
  • Dementia / diagnosis
  • Dementia / diagnostic imaging
  • Diagnosis, Differential
  • Dopa Decarboxylase / metabolism
  • Dopamine Plasma Membrane Transport Proteins / metabolism
  • Essential Tremor / diagnosis
  • Essential Tremor / diagnostic imaging
  • Humans
  • Parkinson Disease / diagnostic imaging*
  • Parkinson Disease / metabolism
  • Parkinsonian Disorders / chemically induced
  • Parkinsonian Disorders / diagnosis
  • Parkinsonian Disorders / diagnostic imaging
  • Positron-Emission Tomography
  • Radioisotopes
  • Receptors, Dopamine D2 / metabolism
  • Tomography, Emission-Computed, Single-Photon
  • Vesicular Monoamine Transport Proteins / metabolism


  • Dopamine Plasma Membrane Transport Proteins
  • Radioisotopes
  • Receptors, Dopamine D2
  • Vesicular Monoamine Transport Proteins
  • Dopa Decarboxylase