title: [(123) I]FP-CIT-SPECT asymmetry index to differentiate Parkinson's disease from vascular parkinsonism.
abstract: OBJECTIVE
  Differential diagnosis between vascular parkinsonism (VP) and Parkinson's Disease (PD) is often difficult, due to the overlap in clinical presentation and the lack of specificity at neuroimaging. Aim of the study was to identify a possible reliable marker at SPECT imaging useful to distinguish the two conditions.
  
  
  METHODS
  We studied 20 PD, 20 VP and 20 essential tremor (ET) patients as control group, who had undergone a cerebral [(123) I] FP-CIT SPECT. A semiquantitative analysis was performed on DaTSCAN SPECT imaging and to establish the degree of asymmetry of the ligand uptake the Striatal Asymmetry Index (SAI) was used.
  
  
  RESULTS
  The binding of the ligand in the most affected side resulted significantly lower in VP than in ET patients but higher compared to PD patients. SAI was significantly higher in PD compared to VP (P < 0.001) and ET (P < 0.001) groups. We found that a cut-off of SAI greater than 14.08 could differentiate PD from VP with a 100% specificity and a 50% sensitivity.
  
  
  CONCLUSIONS
  SAI detected using [(123) I]FP-CIT SPECT can be used to differentiate VP and PD with a good degree of certainty.
authors.affiliation: Department of Neurosciences, University of Catania, Catania, Italy            Section of Catania, Institute of Neurological Sciences (ISN), National Research Council (CNR), Catania, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Contrafatto
authors.forename: G
authors.initials: G
authors.lastname: Mostile
authors.forename: A
authors.initials: A
authors.lastname: Nicoletti
authors.forename: V
authors.initials: V
authors.lastname: Dibilio
authors.forename: L
authors.initials: L
authors.lastname: Raciti
authors.forename: S
authors.initials: S
authors.lastname: Lanzafame
authors.forename: A
authors.initials: A
authors.lastname: Luca
authors.forename: A
authors.initials: A
authors.lastname: Distefano
authors.forename: M
authors.initials: M
authors.lastname: Zappia
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D010302:Parkinson Disease, Secondary / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012680:Sensitivity and Specificity