title: Myocardial perfusion imaging is feasible for infarct size quantification in mice using a clinical single-photon emission computed tomography system equipped with pinhole collimators.
abstract: BACKGROUND
  The aim of this study is to evaluate a non-invasive method for measuring myocardial perfusion defect size in mice using a clinical single-photon emission computed tomography system equipped with pinhole collimators (pinhole SPECT).
  
  
  METHODS
  Thirty days after ligation of the left anterior descending coronary artery, 13 mice (C57BL/6J) were imaged following intravenous injection of 370 MBq [99mTc]sestamibi. Eight control mice without myocardial infarction were likewise investigated. Image quality optimization had been achieved by repeated scanning of a multiple point phantom, with varying zoom factors, number of projection angles, and pinhole diameter. Volumetric sampling was used to generate polar maps, in which intensity was normalized to that of a standard septal region of interest (ROI), which was set at 100%. Receiver operating characteristic analyses were performed to define an optimal threshold as compared to histologically measured defect sizes, which were considered as gold standard.
  
  
  RESULTS
  A spatial resolution of 1.9 mm was achieved using a pinhole diameter of 0.5 mm, a zoom factor of 2, and 6 degrees projection angles. Histological results were best reproduced by a 60% threshold relative to the septal reference ROI. By applying this threshold, SPECT perfusion defect sizes revealed very high correlation to the histological results (R(2) = 0.867) with excellent intra- and interobserver reproducibility (intraclass correlation coefficients of 0.84 and 0.82).
  
  
  CONCLUSIONS
  We achieved a spatial resolution of 1.9 mm in myocardial perfusion imaging in mice using a clinical SPECT system mounted with pinhole collimators. Compared to a histological gold standard, the infarct sizes were accurately estimated, indicating that this method shows promise to monitor experimental cardiac interventions in mice.
authors: Department of Nuclear Medicine, University of Munich, Munich, Germany.
authors: Tim
authors: T
authors: Wollenweber
authors: Christian
authors: C
authors: Zach
authors: Christoph
authors: C
authors: Rischpler
authors: Rebekka
authors: R
authors: Fischer
authors: Sebastian
authors: S
authors: Nowak
authors: Stephan G
authors: SG
authors: Nekolla
authors: Michael
authors: M
authors: Gröbner
authors: Christopher
authors: C
authors: Ubleis
authors: Gerald
authors: G
authors: Assmann
authors: Josef
authors: J
authors: Müller-Höcker
authors: Christian
authors: C
authors: La Fougére
authors: Guido
authors: G
authors: Böning
authors: Paul
authors: P
authors: Cumming
authors: Wolfgang-Michael
authors: WM
authors: Franz
authors: Marcus
authors: M
authors: Hacker
mesh_terms: D000818:Animals; D005240:Feasibility Studies; D051379:Mice; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology*; D010477:Perfusion / Q000295:instrumentation*; D019047:Phantoms, Imaging; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation* / Q000379:methods*