title: The impact of acquisition time of planar cardiac (123)I-MIBG imaging on the late heart to mediastinum ratio.
abstract: OBJECTIVE
  The aim of this study was to investigate whether performing the late cardiac (123)I-metaiodobenzylguanidine (MIBG) scan earlier than 4 h post-injection (p.i.) has relevant impact on the late heart to mediastinum ratio (H/M ratio) in patients with heart failure (HF).
  
  
  METHODS
  Forty-nine patients with HF (median left ventricular ejection fraction of 31 %, 51 % ischaemic HF) referred for cardiac (123)I-MIBG scintigraphy were scanned at 15 min (early) p.i. and at 1, 2, 3 and 4 h (late) p.i. of (123)I-MIBG. Late H/M ratios were calculated and evaluated using a linear mixed model with the mean late H/M ratio at 4 h p.i. as a reference. A difference in late H/M ratios of more than 0.10 between the different acquisition times in comparison with the late H/M ratio at 4 h p.i. was considered as clinically relevant.
  
  
  RESULTS
  Statistically significant mean differences were observed between the late H/M ratios at 1, 2 and 3 h p.i. compared with the late H/M ratio at 4 h p.i. (0.09, 0.05 and 0.02, respectively). However, the mean differences did not exceed the cut-off value of 0.10. On an individual patient level, compared to the late H/M ratio at 4 h p.i., the late H/M ratios at 1, 2 and 3 h p.i. differed more than 0.10 in 24 (50 %), 9 (19 %) and 2 (4 %) patients, respectively.
  
  
  CONCLUSIONS
  Variation in acquisition time of (123)I-MIBG between 2 and 4 h p.i. does not lead to a clinically significant change in the late H/M ratio. An earlier acquisition time seems to be justified and may warrant a more time-efficient cardiac (123)I-MIBG imaging protocol.
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
authors.forename: Aukelien C
authors.initials: AC
authors.lastname: Dimitriu-Leen
authors.affiliation: Fondazione Toscana/CNR Gabriele Monasterio, Pisa, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Gimelli
authors.affiliation: Department of Nuclear Medicine, VieCuri, Venlo, The Netherlands.
authors.forename: Imad
authors.initials: I
authors.lastname: Al Younis
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Veltman
authors.affiliation: Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Hein J
authors.initials: HJ
authors.lastname: Verberne
authors.affiliation: Department of Medical Statistics and Bio-informatics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Ron
authors.initials: R
authors.lastname: Wolterbeek
authors.affiliation: Department of Nuclear Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Silvia
authors.initials: S
authors.lastname: Zandbergen-Harlaar
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. a.j.h.a.scholte@lumc.nl.
authors.forename: Arthur J H A
authors.initials: AJHA
authors.lastname: Scholte
mesh_terms: D019797:3-Iodobenzylguanidine / Q000008:administration & dosage*; D000293:Adolescent; D000328:Adult; D000368:Aged; D004334:Drug Administration Schedule; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006333:Heart Failure / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008482:Mediastinum / Q000000981:diagnostic imaging*; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000008:administration & dosage*
chemical_list: D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine
keywords: 123I-MIBG; Acquisition time; Heart failure; Heart to mediastinum ratio; Planar imaging