title: Timing of cardiovascular MR imaging after acute myocardial infarction: effect on estimates of infarct characteristics and prediction of late ventricular remodeling.
abstract: OBJECTIVE
  To define the evolution of infarct characteristics with cardiovascular magnetic resonance (MR) imaging and to assess which of the cardiovascular MR data acquired at day 2 or at 1 week after acute myocardial infarction (AMI), is the stronger predictor of infarct size and left ventricular (LV) function measured at 3 months.
  
  
  METHODS
  The study protocol was reviewed and approved by the local research ethics committee, and written informed consent was obtained. Forty-eight patients with reperfused AMI underwent cine, T2-weighted, and late gadolinium enhancement cardiovascular MR imaging at days 2, 7, 30, and 90 after index presentation. Continuous data between times were compared by using paired t tests or one-way analysis of variance. Multiple linear regression analyses were used to predict linear end points.
  
  
  RESULTS
  Infarct size and extent of myocardial edema decreased significantly between day 2 and 1 week: Mean scar as a percentage of LV mass and standard deviation (SD), respectively, were 27.2 and 13.9 versus 21.6 and 14.1 (P < .001), and myocardial edema as a percentage of LV mass and SD, respectively, were 37.9 and 15.2 versus 32.3 and 14.3 (P = .003). These changes were accompanied by a significant improvement in LV ejection fraction (LVEF): Mean percentage of LVEF and SD, respectively, were 41.7 and 9.6 versus 44.6 and 10.1 (P < .001). When comparing data acquired at day 2 and 1 week, only cardiovascular MR data acquired at 1 week were independent predictors of LVEF and infarct size at 3 months.
  
  
  CONCLUSIONS
  LVEF, infarct size, and extent of myocardial edema changed significantly during the 1st week after AMI. Overall, cardiovascular MR measurements acquired after 1 week have greater predictive value for infarct size and LV function at 3 months than data acquired at day 2.
authors.affiliation: Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Neuronal Remodelling, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Jubilee Wing, Leeds General Infirmary, Leeds LS1 3EX, England.
authors.forename: Adam N
authors.initials: AN
authors.lastname: Mather
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Fairbairn
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Artis
authors.forename: John P
authors.initials: JP
authors.lastname: Greenwood
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
mesh_terms: D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D020257:Ventricular Remodeling