Strain rate imaging differentiates transmural from non-transmural myocardial infarction: a validation study using delayed-enhancement magnetic resonance imaging.
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.
Zhang
Yan
Y
Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, SAR.
Chan
Anna K Y
AK
Yu
Cheuk-Man
CM
Yip
Gabriel W K
GW
Fung
Jeffrey W H
JW
Lam
Wynnie W M
WW
So
Nina M C
NM
Wang
Mei
M
Wu
Eugene B
EB
Wong
John T
JT
Sanderson
John E
JE
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
D003287:Contrast Media; D019786:Gadolinium DTPA