title: Performance of CMR Methods for Differentiating Acute From Chronic MI.
abstract: OBJECTIVE
  The purpose of this study was to assess the performance of cardiac magnetic resonance (CMR) methods for discriminating acute from chronic myocardial infarction (MI).
  
  
  BACKGROUND
  Although T2-weighted CMR is thought to be accurate in differentiating acute from chronic MI, few studies have reported on diagnostic accuracy, and these generally compared extremes in infarct age (e.g., <1 week old vs. more than 6 months old) and did not evaluate other CMR methods that could be informative.
  
  
  METHODS
  A total of 221 CMR studies were performed at various time points after ST-segment elevation myocardial infarction in 117 consecutive patients without a history of MI or revascularization enrolled prospectively at 2 centers. Imaging markers of acute MI (<1 month) were T2 hyperintensity on double inversion recovery turbo spin echo (DIR-TSE) images, microvascular obstruction (MO) on delayed-enhancement CMR, and focally increased end-diastolic wall thickness (EDWT) on cine-CMR.
  
  
  RESULTS
  The prevalence of T2-DIR-TSE hyperintensity decreased with infarct age but remained substantial up to 6 months post-MI. In contrast, the prevalence of both MO and increased EDWT dropped sharply after 1 month. T2-DIR-TSE sensitivity, specificity, and accuracy for identifying acute MI were 88%, 66%, and 77% compared with 73%, 97%, and 85%, respectively, for the combination of MO or increased EDWT. On multivariable analysis, persistence of T2-hyperintensity in intermediate-age infarcts (1 to 6 months old) was predicted by larger infarct size, diabetes, and better T2-DIR-TSE image quality score. For infarct size ≥ 10% of the left ventricle, a simple algorithm incorporating all CMR components allowed classification of infarct age into 3 categories (<1 month old, 1 to 6 months old, and ≥ 6 months old) with 80% (95% confidence interval: 73% to 87%) accuracy.
  
  
  CONCLUSIONS
  T2-DIR-TSE hyperintensity is specific for infarcts <6 months old, whereas MO and increased EDWT are specific for infarcts <1 month old. Incorporating multiple CMR markers of acute MI and their varied longevity leads to a more precise assessment of infarct age.
authors.affiliation: Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Martijn W
authors.initials: MW
authors.lastname: Smulders
authors.affiliation: Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Sebastiaan C A M
authors.initials: SC
authors.lastname: Bekkers
authors.affiliation: Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, Durham, North Carolina; Division of Cardiology, Duke University Medical Center, Durham, North Carolina.
authors.forename: Han W
authors.initials: HW
authors.lastname: Kim
authors.affiliation: Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, Durham, North Carolina.
authors.forename: Lowie M R
authors.initials: LM
authors.lastname: Van Assche
authors.affiliation: Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, Durham, North Carolina.
authors.forename: Michele A
authors.initials: MA
authors.lastname: Parker
authors.affiliation: Duke Cardiovascular Magnetic Resonance Center, Duke University Medical Center, Durham, North Carolina; Division of Cardiology, Duke University Medical Center, Durham, North Carolina; Department of Radiology, Duke University Medical Center, Durham, North Carolina. Electronic address: Raymond.kim@duke.edu.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Kim
mesh_terms: D000208:Acute Disease; D002908:Chronic Disease; D003937:Diagnosis, Differential; D005260:Female; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D015203:Reproducibility of Results; D013997:Time Factors
keywords: T2-weighted CMR; acute MI; microvascular obstruction