title: Strain rate imaging differentiates transmural from non-transmural myocardial infarction: a validation study using delayed-enhancement magnetic resonance imaging.
abstract: OBJECTIVE
  The aim of this study was to determine if strain rate imaging (SRI) correlates with the transmural extent of myocardial infarction (MI) measured by contrast-enhanced magnetic resonance imaging (Ce-MRI).
  
  
  BACKGROUND
  Identification of the transmural extent of myocardial necrosis and degree of non-viability after acute MI is clinically important.
  
  
  METHODS
  Tissue Doppler echocardiography with SRI and Ce-MRI were performed in 47 consecutive patients with a first acute MI between days 2 and 6 and compared to 60 age-matched healthy volunteers. Peak myocardial velocities and peak myocardial deformation strain rates were measured. Location and size of the infarct zone was confirmed by Ce-MRI using the delayed enhancement technique with a 16-segment model.
  
  
  RESULTS
  Contrast-enhanced MRI identified transmural infarction in 21 patients, non-transmural infarction in 15 (mean transmurality of infarct 72.3 +/- 10.6%), and another 11 patients with subendocardial infarction (<50% transmural extent of the left ventricular wall). Peak systolic strain rate (SRs) of the transmural infarction segments was significantly lower compared to normal myocardium or with non-transmural infarction segments (both p < 0.0005). A cutoff value of SRs >-0.59 s(-1) detected a transmural infarction with high sensitivity (90.9%) and high specificity (96.4%), and -0.98 s(-1) >SRs >-1.26 s(-1) distinguished subendocardial infarction from normal myocardium with a sensitivity of 81.3% and a specificity of 83.3%.
  
  
  CONCLUSIONS
  Peak myocardial deformation by SRI can differentiate transmural from non-transmural MI, and it allows noninvasive determination of transmurality of the scar after MI and thereby the extent of non-viable myocardium.
authors.affiliation: Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, SAR.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Anna K Y
authors.initials: AK
authors.lastname: Chan
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu
authors.forename: Gabriel W K
authors.initials: GW
authors.lastname: Yip
authors.forename: Jeffrey W H
authors.initials: JW
authors.lastname: Fung
authors.forename: Wynnie W M
authors.initials: WW
authors.lastname: Lam
authors.forename: Nina M C
authors.initials: NM
authors.lastname: So
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Eugene B
authors.initials: EB
authors.lastname: Wu
authors.forename: John T
authors.initials: JT
authors.lastname: Wong
authors.forename: John E
authors.initials: JE
authors.lastname: Sanderson
mesh_terms: D000208:Acute Disease; D000368:Aged; D016022:Case-Control Studies; D003287:Contrast Media; D023921:Coronary Stenosis / Q000175:diagnosis; D015150:Echocardiography, Doppler; D005260:Female; D019786:Gadolinium DTPA; D006723:Hong Kong; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000000981:diagnostic imaging; D013997:Time Factors
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA