title: Hybrid SPECT/cardiac-gated first-pass perfusion CT: locating transplanted cells relative to infarcted myocardial targets.
abstract: OBJECTIVE
  A challenge with cardiac cell therapy is determining the location of cells relative to infarct tissue. As cells are viable following ¹¹¹In-labeling, and first-pass CT imaging can identify regions of myocardial infarction, we evaluated the feasibility of a SPECT/CT system to localize cells relative to infarcted myocardium in a canine model.
  
  
  METHODS
  Ten canines underwent surgical ligation of the left-anterior-descending artery and endothelial progenitor cells labeled with ¹¹¹In-tropolone were transplanted endocardially or epicardially. SPECT/CT was performed on day of transplantation, 4 and 10 days post-transplantation. For each imaging session first-pass perfusion CT was performed to delineate the area of reduced perfusion. SPECT and first-pass CT images were fused and evaluated. Contrast-to-noise ratios (CNR) were calculated for ¹¹¹In-SPECT images to evaluate cell detection.
  
  
  RESULTS
  The zone of reduced perfusion was well delineated on first-pass perfusion CT in all canines. The ¹¹¹In signal was visualized within this zone in all cases. Analysis of the CNRs suggests that cells may be followed for 11 effective half-lives using the images from first-pass perfusion CT to provide the anatomic landmarks.
  
  
  CONCLUSIONS
  In the setting of an acute myocardial infarction SPECT/[first-pass perfusion CT] is an effective hybrid platform for the localization of cells in relation to the area of reduced blood flow.
authors.affiliation: Lawson Health Research Institute Imaging Program, Rm E5-109, St Joseph's Hospital, 268 Grosvenor St, London, ON, Canada. esabondj@lawsonimaging.ca
authors.forename: Eric
authors.initials: E
authors.lastname: Sabondjian
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Mitchell
authors.forename: Gerald
authors.initials: G
authors.lastname: Wisenberg
authors.forename: James
authors.initials: J
authors.lastname: White
authors.forename: Kimberley J
authors.initials: KJ
authors.lastname: Blackwood
authors.forename: Jane
authors.initials: J
authors.lastname: Sykes
authors.forename: Lela
authors.initials: L
authors.lastname: Deans
authors.forename: Robert Z
authors.initials: RZ
authors.lastname: Stodilka
authors.forename: Frank S
authors.initials: FS
authors.lastname: Prato
mesh_terms: D000818:Animals; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography / Q000379:methods*; D002470:Cell Survival; D058948:Cell Tracking / Q000379:methods*; D003287:Contrast Media / Q000493:pharmacokinetics; D004285:Dogs; D005260:Female; D006085:Graft Survival; D007205:Indium Radioisotopes / Q000493:pharmacokinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D059629:Signal-To-Noise Ratio; D033581:Stem Cell Transplantation; D014334:Tropolone / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
chemical_list: D003287:Contrast Media; D007205:Indium Radioisotopes; D009942:Organometallic Compounds; C043895:indium tris(tropolonate); D014334:Tropolone