title: Strain rate imaging combined with wall motion analysis gives incremental value in direct quantification of myocardial infarct size.
abstract: BACKGROUND
  The study aimed to evaluate the diagnostic accuracy of a new method for direct echocardiographic quantification of the myocardial infarct size, using late enhancement magnetic resonance imaging (LE-MRI) as a reference method.
  
  
  RESULTS
  Echocardiography and LE-MRI were performed on average 31 days after first-time myocardial infarction in 58 patients. Echocardiography was also performed on 35 healthy controls. Direct echocardiographic quantification of the infarct size was based on automated selection and quantification of areas with hypokinesia and akinesia from colour-coded strain rate data, with manual correction based on visual wall motion analysis. The left ventricular (LV) ejection fraction, speckle-tracking-based longitudinal global strain, wall motion score index (WMSI), longitudinal systolic motion and velocity, and the ratio of early mitral inflow velocity to mitral annular early diastolic velocity were also measured by echocardiography. The area under the receiver-operating characteristic curves for the identification of the infarct size >12% by LE-MRI was 0.84, using the new method for direct echocardiographic quantification of the infarct size. The new method showed significantly a higher correlation with the infarct size by LE-MRI both at the global (r = 0.81) and segmental (r = 0.59) level compared with other indices of LV function.
  
  
  CONCLUSIONS
  Direct quantification of the percentage infarct size by strain rate imaging combined with wall motion analysis yields high diagnostic accuracy and better correlation to LE-MRI compared with other echocardiographic indices of global LV function. Echocardiography performed ~1 month after myocardial infarction showed ability to identify the patients with the infarct size >12%.
authors.affiliation: MI Lab and Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, MTFS, Postboks 8905, NO-7491, Trondheim, Norway. anders.thorstensen@ntnu.no
authors.forename: Anders
authors.initials: A
authors.lastname: Thorstensen
authors.forename: Brage Høyem
authors.initials: BH
authors.lastname: Amundsen
authors.forename: Håvard
authors.initials: H
authors.lastname: Dalen
authors.forename: Pavel
authors.initials: P
authors.lastname: Hala
authors.forename: Gabriel
authors.initials: G
authors.lastname: Kiss
authors.forename: Svein Arne
authors.initials: SA
authors.lastname: Aase
authors.forename: Hans
authors.initials: H
authors.lastname: Torp
authors.forename: Asbjørn
authors.initials: A
authors.lastname: Støylen
mesh_terms: D000367:Age Factors; D003287:Contrast Media; D004452:Echocardiography / Q000379:methods; D005260:Female; D005682:Gadolinium; D006305:Health Status Indicators; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D009203:Myocardial Infarction / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D055414:Myocardial Perfusion Imaging; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D013318:Stroke Volume / Q000502:physiology*; D013599:Systole; D016277:Ventricular Function, Left
chemical_list: D003287:Contrast Media; D005682:Gadolinium