title: Observer reproducibility of results from a low-dose 123I-metaiodobenzylguanidine cardiac imaging protocol in patients with heart failure.
abstract: OBJECTIVE
  Imaging of the cardiac autonomic system with (123)I-metaiodobenzylguanidine (MIBG) is useful in the evaluation of patients with a variety of cardiac conditions, including heart failure (HF), but few data are available about the reproducibility of this technique. We assessed the observer reproducibility of the results from a low-dose (123)I-MIBG cardiac imaging protocol in patients with HF.
  
  
  METHODS
  A total of 74 patients (62 men, age 67 ± 10 years) with HF and left ventricular systolic dysfunction (ejection fraction 31 ± 7 %) underwent low-dose (111 MBq) planar and single-photon emission computed tomography (SPECT) (123)I-MIBG cardiac sympathetic imaging. The intraclass coefficient of correlation (ICC), Lin's concordance correlation coefficient, and Bland-Altman analysis were used to evaluate the intraobserver and interobserver reproducibility of early and late heart-to-mediastinum (H/M) ratios and of defect scores on SPECT images. The κ statistic was used to evaluate the concordance rates for the identification of patients with a low H/M ratio (<1.60) on late planar imaging.
  
  
  RESULTS
  The differences between measurements obtained twice by the same examiner and by two examiners were negligible for both early and late H/M ratios and for SPECT defect scores. These findings were confirmed by the results of Bland-Altman analysis, and ICC and Lin's coefficient values were excellent (>0.90) for all measurements. For the identification of patients with a low H/M ratio, the κ values were 0.90 for intraobserver concordance and 0.83 for interobserver concordance.
  
  
  CONCLUSIONS
  The present study showed a high observer reproducibility of planar H/M ratios and SPECT defect scores using a low-dose (123)I-MIBG cardiac imaging protocol in patients with HF.
authors.affiliation: Institute of Biostructure and Bioimaging, National Council of Research, Naples, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Pellegrino
authors.forename: Mario
authors.initials: M
authors.lastname: Petretta
authors.forename: Serena
authors.initials: S
authors.lastname: De Luca
authors.forename: Stefania
authors.initials: S
authors.lastname: Paolillo
authors.forename: Antonio
authors.initials: A
authors.lastname: Boemio
authors.forename: Raffaella
authors.initials: R
authors.lastname: Carotenuto
authors.forename: Maria Piera
authors.initials: MP
authors.lastname: Petretta
authors.forename: Carmine
authors.initials: C
authors.lastname: di Nuzzo
authors.forename: Pasquale
authors.initials: P
authors.lastname: Perrone-Filardi
authors.forename: Alberto
authors.initials: A
authors.lastname: Cuocolo
mesh_terms: D019797:3-Iodobenzylguanidine; D000368:Aged; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine