title: Update on SPECT and PET in parkinsonism - part 2: biomarker imaging of cognitive impairment in Lewy-body diseases.
abstract: OBJECTIVE
  To give an update on recent biomarker imaging studies using single-photon emission computed tomography (SPECT) and positron emission tomography (PET) on cognitive impairment in Lewy-body diseases (LBD).
  
  
  RESULTS
  Imaging studies of regional cerebral glucose metabolism with [F]fluorodeoxyglucose(FDG)-PET support the concept that Parkinson's disease (PD) with mild cognitive impairment represents a prodromal stage of PD with dementia (PDD). Furthermore, [F]FDG-PET may be suited for risk stratification for dementia in PD. In line with neuropathological studies, preliminary amyloid-beta (Aβ) PET studies suggest that Aβ acts synergistically with Lewy pathology in LBD, leading to an earlier manifestation of cognitive impairment in dementia with Lewy-bodies compared with PDD and a more rapid cognitive decline in PD patients with concomitant Aβ pathology.
  
  
  CONCLUSIONS
  Molecular neuroimaging with SPECT and PET provides unique in-vivo insights into neuropathological and pathophysiological changes underlying cognitive impairment in LBD. Future prospective studies are needed to confirm the prognostic value of [F]FDG-PET and to define the value of amyloid PET and upcoming techniques, such as tau imaging, for diagnosis and prognosis in LBD.
authors: aDepartment of Nuclear Medicine bCentre of Geriatrics and Gerontology cDepartment of Neurology dDepartment of Psychiatry and Psychotherapy, University Hospital Freiburg, Freiburg, Germany.
authors: Philipp T
authors: PT
authors: Meyer
authors: Lars
authors: L
authors: Frings
authors: Sabine
authors: S
authors: Hellwig
mesh_terms: D003072:Cognition Disorders / Q000000981:diagnostic imaging* / Q000209:etiology*; D006801:Humans; D020961:Lewy Body Disease / Q000150:complications* / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*