title: The impact of reconstruction and scanner characterisation on the diagnostic capability of a normal database for [123I]FP-CIT SPECT imaging.
abstract: BACKGROUND
  The use of a normal database for [123I]FP-CIT SPECT imaging has been found to be helpful for cases which are difficult to interpret by visual assessment alone, and to improve reproducibility in scan interpretation. The aim of this study was to assess whether the use of different tomographic reconstructions affects the performance of a normal [123I]FP-CIT SPECT database and also whether systems benefit from a system characterisation before a database is used. Seventy-seven [123I]FP-CIT SPECT studies from two sites and with 3-year clinical follow-up were assessed quantitatively for scan normality using the ENC-DAT normal database obtained in well-documented healthy subjects. Patient and normal data were reconstructed with iterative reconstruction with correction for attenuation, scatter and septal penetration (ACSC), the same reconstruction without corrections (IRNC), and filtered back-projection (FBP) with data quantified using small volume-of-interest (VOI) (BRASS) and large VOI (Southampton) analysis methods. Test performance was assessed with and without system characterisation, using receiver operating characteristics (ROC) analysis for age-independent data and using sensitivity/specificity analysis with age-matched normal values. The clinical diagnosis at follow-up was used as the standard of truth.
  
  
  RESULTS
  There were no significant differences in the age-independent quantitative assessment of scan normality across reconstructions, system characterisation and quantitative methods (ROC AUC 0.866-0.924). With BRASS quantification, there were no significant differences between the values of sensitivity (67.4-83.7%) or specificity (79.4-91.2%) across all reconstruction and calibration strategies. However, the Southampton method showed significant differences in sensitivity between ACSC (90.7%) vs IRNC (76.7%) and FBP (67.4%) reconstructions with calibration. Sensitivity using ACSC reconstruction with this method was also significantly better with calibration than without calibration (65.1%). Specificity using the Southampton method was unchanged across reconstruction and calibration choices (82.4-88.2%).
  
  
  CONCLUSIONS
  The ability of a normal [123I]FP-CIT SPECT database to assess clinical scan normality is equivalent across all reconstruction, system characterisation, and quantification strategies using BRASS quantification. However, when using the Southampton quantification method, performance is sensitive to the reconstruction and calibration strategy used.
authors.affiliation: Institute of Nuclear Medicine, University College London Hospital NHS Foundation Trust, 235 Euston Road, London, NW1 2BU, UK. john.dickson2@nhs.net.
authors.forename: John C
authors.initials: JC
authors.lastname: Dickson
authors.affiliation: Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: Livia
authors.initials: L
authors.lastname: Tossici-Bolt
authors.affiliation: Department of Nuclear Medicine and Euromedic Szeged, University of Szeged, Szeged, Hungary.
authors.forename: Terez
authors.initials: T
authors.lastname: Sera
authors.affiliation: Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Booij
authors.affiliation: Neurobiology Research Unit, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Ziebell
authors.affiliation: Nuclear Medicine Unit, Department of Health Sciences, IRCCS San Martino-IST, University of Genoa, Genoa, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Morbelli
authors.affiliation: Department of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Susanne
authors.initials: S
authors.lastname: Assenbaum-Nan
authors.affiliation: Nuclear Medicine Division, Université Catholique de Louvain, Mont-Godinne Medical Center, Louvain-la-Neuve, Belgium.
authors.forename: Thierry Vander
authors.initials: TV
authors.lastname: Borght
authors.affiliation: Institute of Cognitive Sciences and Technologies, CNR, Rome, Italy.|Department of Nuclear Medicine, Karolinska Hospital, Stockholm, Sweden.
authors.forename: Marco
authors.initials: M
authors.lastname: Pagani
authors.affiliation: Department of Nuclear Medicine, Faculty of Medicine, Gazi University, Ankara, Turkey.
authors.forename: Ozlem L
authors.initials: OL
authors.lastname: Kapucu
authors.affiliation: Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany.
authors.forename: Swen
authors.initials: S
authors.lastname: Hesse
authors.affiliation: Division of Nuclear Medicine, University Hospital and K.U. Leuven, Leuven, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Van Laere
authors.affiliation: Nuclear Medicine, Centre Antoine Lacassagne and University Hospital, Université de Nice de Sophia Antipolis, Nice, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Darcourt
authors.affiliation: Department of Clinical Neuroscience Psychiatry Section, Karolinska Institute, Stockholm, Sweden.
authors.forename: Andrea
authors.initials: A
authors.lastname: Varrone
authors.affiliation: Department of Nuclear Medicine, Municipal Hospital of Karlsruhe Inc., Karlsruhe, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Tatsch
keywords: Dopamine transporter; Quantification; Reconstruction; SPECT; [123I]FP-CIT