title: ¹²³I-FP-Cit and 123I-IBZM SPECT uptake in a prospective normal material analysed with two different semiquantitative image evaluation tools.
abstract: OBJECTIVE
  The need for age-adjusted and/or sex-adjusted reference values in dopamine transporter (DAT) and dopamine D2 receptor (D2R) imaging with single-photon emission computed tomography (SPECT) in a longitudinal study of parkinsonian diseases was investigated. We used two different image evaluation tools with a cross-sectional and longitudinal statistical approach.
  
  
  METHODS
  Baseline DAT and/or D2R SPECT were performed in 51 healthy controls (HC), age-matched to patients in an ongoing prospective study on idiopathic parkinsonism. Twenty-four HC were re-examined after 3 years and 21 HC were examined again after 5 years. SPECT was performed with I-FP-Cit and I-IBZM on a two-headed hybrid gamma camera. Regions of interest and volumes of interest (VOIs) were used for image evaluation. A cross-sectional and longitudinal statistical analysis was carried out.
  
  
  RESULTS
  Fewer sex-based differences and less age dependency were seen in DAT SPECT uptake ratios compared with D2R SPECT uptake ratios and when comparing uptake ratios obtained with regions of interest against those with VOIs. In the cross-sectional analysis, a significant age-dependent decline was seen in women in both DAT and D2R uptakes with the VOI method but not in men with either evaluation method. In the longitudinal dataset, both a slight decline and increase over time were seen in DAT uptake; however, a general pattern of decrease was seen in both men and women in D2R uptake.
  
  
  CONCLUSIONS
  The choice of the image evaluation method can influence the pattern of sex-based and age-related differences. The results speak for the use of age-stratified reference values for women, in particular when using a VOI method.
authors.affiliation: Department of Radiation Sciences, Diagnostic Radiology, Epidemiology and Global Health, Umeå University, Sweden. susanna.jakobson.mo@diagrad.umu.se
authors.forename: Susanna
authors.initials: S
authors.lastname: Jakobson Mo
authors.forename: Anne
authors.initials: A
authors.lastname: Larsson
authors.forename: Jan
authors.initials: J
authors.lastname: Linder
authors.forename: Richard
authors.initials: R
authors.lastname: Birgander
authors.forename: Lars
authors.initials: L
authors.lastname: Edenbrandt
authors.forename: Hans
authors.initials: H
authors.lastname: Stenlund
authors.forename: Lars
authors.initials: L
authors.lastname: Forsgren
authors.forename: Katrine
authors.initials: K
authors.lastname: Riklund
mesh_terms: D000328:Adult; D000368:Aged; D001549:Benzamides / Q000378:metabolism; D001692:Biological Transport; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D011446:Prospective Studies; D011759:Pyrrolidines / Q000378:metabolism; D012016:Reference Values; D013569:Synapses / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods* / Q000592:standards; D014326:Tropanes / Q000378:metabolism
chemical_list: D001549:Benzamides; D050483:Dopamine Plasma Membrane Transport Proteins; D011759:Pyrrolidines; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide