title: Value of semiquantitative analysis for clinical reporting of 123I-2-β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane SPECT studies.
abstract: Clinical (123)I-2-β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane ((123)I-FP-CIT) SPECT studies are commonly performed and reported using visual evaluation of tracer binding, an inherently subjective method. Increased objectivity can potentially be obtained using semiquantitative analysis. In this study, we assessed whether semiquantitative analysis of (123)I-FP-CIT tracer binding created more reproducible clinical reporting. A secondary aim was to determine in what form semiquantitative data should be provided to the reporter.
  
  
  METHODS
  Fifty-four patients referred for the assessment of nigrostriatal dopaminergic degeneration were scanned using SPECT/CT, followed by semiquantitative analysis calculating striatal binding ratios (SBRs) and caudate-to-putamen ratios (CPRs). Normal reference values were obtained using 131 healthy controls enrolled on a multicenter initiative backed by the European Association of Nuclear Medicine. A purely quantitative evaluation was first performed, with each striatum scored as normal or abnormal according to reference values. Three experienced nuclear medicine physicians then scored each striatum as normal or abnormal, also indicating cases perceived as difficult, using visual evaluation, visual evaluation in combination with SBR data, and visual evaluation in combination with SBR and CPR data. Intra- and interobserver agreement and agreement between observers and the purely quantitative evaluation were assessed using κ-statistics. The agreement between scan interpretation and clinical diagnosis was assessed for patients with a postscan clinical diagnosis available (n = 35).
  
  
  RESULTS
  The physicians showed consistent reporting, with a good intraobserver agreement obtained for the visual interpretation (mean κ ± SD, 0.95 ± 0.029). Although visual interpretation of tracer binding gave good interobserver agreement (0.80 ± 0.045), this was improved as SBRs (0.86 ± 0.070) and CPRs (0.95 ± 0.040) were provided. The number of striata perceived as difficult to interpret decreased as semiquantitative data were provided (30 for the visual interpretation; 0 as SBR and CPR values were given). The agreement between physicians' interpretations and the purely quantitative evaluation showed that readers used the semiquantitative data to different extents, with a more experienced reader relying less on the semiquantitative data. Good agreement between scan interpretation and clinical diagnosis was seen.
  
  
  CONCLUSIONS
  A combined approach of visual assessment and semiquantitative analysis of tracer binding created more reproducible clinical reporting of (123)I-FP-CIT SPECT studies. Physicians should have access to both SBR and CPR data to minimize interobserver variability.
authors.affiliation: Institute of Nuclear Medicine, University College London Hospitals NHS Foundation Trust, London, United Kingdom. therese.soderlund@uclh.nhs.uk
authors.forename: Therese A
authors.initials: TA
authors.lastname: Söderlund
authors.forename: John C
authors.initials: JC
authors.lastname: Dickson
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Prvulovich
authors.forename: Simona
authors.initials: S
authors.lastname: Ben-Haim
authors.forename: Paul
authors.initials: P
authors.lastname: Kemp
authors.forename: Jan
authors.initials: J
authors.lastname: Booij
authors.forename: Flavio
authors.initials: F
authors.lastname: Nobili
authors.forename: Gerda
authors.initials: G
authors.lastname: Thomsen
authors.forename: Osama
authors.initials: O
authors.lastname: Sabri
authors.forename: Pierre-Malik
authors.initials: PM
authors.lastname: Koulibaly
authors.forename: Ozgur U
authors.initials: OU
authors.lastname: Akdemir
authors.forename: Marco
authors.initials: M
authors.lastname: Pagani
authors.forename: Koen
authors.initials: K
authors.lastname: van Laere
authors.forename: Susanne
authors.initials: S
authors.lastname: Asenbaum-Nan
authors.forename: Jean
authors.initials: J
authors.lastname: George
authors.forename: Terez
authors.initials: T
authors.lastname: Sera
authors.forename: Klaus
authors.initials: K
authors.lastname: Tatsch
authors.forename: Jamshed
authors.initials: J
authors.lastname: Bomanji
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012107:Research Design; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes; D055815:Young Adult
chemical_list: D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane
keywords: 123I-FP-CIT; dopamine transporter; observer variability; semiquantification