All CMR studies were performed on a 1.5‐T Signa Twinspeed scanner using a 4‐element cardiac phased–array coil (General Electric Medical Systems, Waukesha, WI) as previously described.16 , 25 Images were acquired during breath‐hold and triggered to the ECG or to pulse oximetry if ECG gating was suboptimal.
Late gadolinium enhancement imaging has been validated in both small and large animals, and in an international randomized controlled trial.26 , 27 , 28 , 29 Imaging was performed to evaluate MI scar, typically 6 to 15 minutes after injection of gadopentetate dimeglumine at low dose (0.1 mmol/kg; Magnevist, Schering AG, Berlin, Germany), using a phase‐sensitive segmentation gradient echo inversion recovery sequence.25 Calculated median glomerular filtration rate was 69 (interquartile range 59–82) mL/min per 1.73 m2 and no subject had significant renal failure.16 , 30 Using the 17‐segment standardized model of the American Heart Association,31 the diagnosis of MI was based on consensus of 2 cardiologists experienced in CMR and blinded to subject clinical characteristics. For each segment, MI scar was considered present if the detected lesion had endocardial involvement and followed a coronary distribution. Scar patterns considered atypical for MI were not designated as MI. The size of left ventricular infarct was expressed as a percentage of total left ventricle.
Late gadolinium enhancement imaging has been validated in both small and large animals, and in an international randomized controlled trial.