title: Localization and determination of infarct size by Gd-Mesoporphyrin enhanced MRI in dogs.
abstract: BACKGROUND
  Accurate localization and sizing of a myocardial infarction are necessary for clinical decision making and even more in research. Gd-Mesoporphyrin enhanced magnetic resonance imaging (MRI) was recently shown to specifically delineate necrosis in liver tumors, renal and muscle necrosis and myocardial infarction in rats. In this study, we investigated this technique's potential to accurately delineate myocardial infarction in a larger animal species, the dog.
  
  
  METHODS
  Myocardial infarction was induced in 8 dogs by ligation of the left anterior descending coronary artery, 4 of which were reperfused after 3 hr Gd-Mesoporphyrin (0.05 mmol/kg) was injected intravenously 210 min after the onset of ischemia (n = 6) or after 24 hr in 2 dogs with non-reperfused infarctions. MRI was performed 10 hr after administration of Gd-Mesoporphyrin. In vivo MRI consisted of EKG-triggered, respiratory gated T1-weighted spin echo and segmented turboFLASH long and short axis measurements. Post-mortem, a spin echo short axis measurement was repeated. Infarct size was determined planimetrically by TTC staining of left ventricular slices.
  
  
  RESULTS
  In all instances, there was a very close qualitative agreement between the MRI and TTC defined myocardial infarction. Quantitatively, the linear regression from post-mortem MRI to TTC determined infarct size yielded a result very close to the line of identity (regression coefficient: 0.980 +/- 0.026, p < 0.000001, adjusted R2 = 0.964).
  
  
  CONCLUSIONS
  We conclude that Gd-Mesoporphyrin enhanced MRI is a promising tool for the accurate delineation of myocardial infarction.
authors.affiliation: Center for Experimental Surgery and Anaesthesiology, K.U. Leuven, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Herijgers
authors.forename: S K
authors.initials: SK
authors.lastname: Laycock
authors.forename: Y
authors.initials: Y
authors.lastname: Ni
authors.forename: G
authors.initials: G
authors.lastname: Marchal
authors.forename: J
authors.initials: J
authors.lastname: Bogaert
authors.forename: H
authors.initials: H
authors.lastname: Bosmans
authors.forename: C
authors.initials: C
authors.lastname: Petré
authors.forename: W
authors.initials: W
authors.lastname: Flameng
mesh_terms: D000818:Animals; D004396:Coloring Agents; D004285:Dogs; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008665:Metalloporphyrins; D009203:Myocardial Infarction / Q000175:diagnosis*; D013778:Tetrazolium Salts
chemical_list: D004396:Coloring Agents; D008665:Metalloporphyrins; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium; D005682:Gadolinium