Background Assessment of transmural extent (TME) of necrosis after acute myocardial infarction (MI) remains a major problem in clinical practice.Methods The study sought to determine whether speckle tracking imaging (STI) could differentiate transmural from nontransmural acute MI by assessment of endocardial and epicardiai torsion.TME of infarct was measured by contrast-enhanced magnetic resonance imaging.Patients were divided into two groups according to TME (transmural MI group (TME 50％, n=36) and nontransmural MI group (TME 50％, n=35)).As a control group, 30 subjects without evidence of structural heart disease were included.Conventional echocardiography and STI were done in controls and patients before and 1 month after percutaneous coronary intervention.