title: Acute and chronic myocardial infarction in a pig model: utility of multi-slice cardiac computed tomography in assessing myocardial viability and infarct parameters.
abstract: OBJECTIVE
  The aim of this study was to determine the feasibility of multi-slice computed tomography (MSCT) biphasic imaging in assessing myocardial viability and infarct parameters in both acutely and chronically infarcted pig models.
  
  
  METHODS
  Seven pigs underwent ligation of the distal left anterior descending artery. Imaging was performed on the day of infarction and 3 months post-infarct, with contrast infusion followed by MSCT scan acquisition at different time-points. Left ventricular ejection fractions (LVEFs) were obtained by left ventriculography (LVG) after 3 months. Infarcted locations found using MSCT were compared with those obtained using SPECT. Infarcted areas were also analysed histopathologically and compared with the findings from MSCT.
  
  
  RESULTS
  Chronic phase images had perfusion defects with lower CT values relative to normal myocardium (43±10HU vs. 156±13HU, p=0.001) on the early images but no residual defects on delayed images. However, we found hyperenhancing regions on delayed images (244±20HU vs. 121±25HU, p=0.001), and good correlation between MSCT- and LVG-derived LVEFs (60.56±7.56%). The areas identified by MSCT corresponded to the location of (201)Tl SPECT-/pathologic staining-derived regions in all models. Infarct size was in good agreement with MSCT and pathological analyses of chronic phase models.
  
  
  CONCLUSIONS
  Necrotic myocardium in different stages after infarction could be qualitatively and quantitatively assessed using MSCT biphasic imaging, as could the status of microcirculation formation. MSCT-measured LVEFs matched well with other modalities, and hence MSCT is a useful tool in assessing post-infarct cardiac function.
authors.affiliation: Department of Cardiology and Radiology, Shanghai Chest Hospital, Shanghai Jiaotong University, No. 241, West Huaihai Road, Shanghai, 200030, China.
authors.forename: Xinkai
authors.initials: X
authors.lastname: Qu
authors.forename: Weiyi
authors.initials: W
authors.lastname: Fang
authors.forename: Jianding
authors.initials: J
authors.lastname: Ye
authors.forename: Angela S
authors.initials: AS
authors.lastname: Koh
authors.forename: Yingjia
authors.initials: Y
authors.lastname: Xu
authors.forename: Shaofeng
authors.initials: S
authors.lastname: Guan
authors.forename: Ruogu
authors.initials: R
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Shen
mesh_terms: D000208:Acute Disease; D000818:Animals; D002908:Chronic Disease; D003937:Diagnosis, Differential; D004195:Disease Models, Animal; D005240:Feasibility Studies; D006801:Humans; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology