Myocardial Infarction Detection Using Combined Myocardial Elastography and Electromechanical Wave Imaging

Myocardial Infarction (MI), more colloquially known as heart attack, is the leading cause of death across most demographic lines in the United States [1]. Early detection, as well as understanding of the extent of the damage done are imperative to survival and recovery. MI occurs when the myocardium, or heart wall, lacks sufficient blood supply, and is thereby deprived of oxygen. This will immediately cause ischemia, an area of low perfusion, and then infarction, an area which lacks perfusion of oxygenated blood flow. Myocardial Elastography (ME) is a strain estimation technique using a 1-D cross-correlation algorithm in a 2-D search, then a least-squares strain estimator, on RF data acquired at 300 Hz. ME has been shown to be able to detect radial strain defects resulting from blockages of the main arteries which supply blood to the ventricular myocardium [sources]. Electromechanical Wave Imaging (EWI) seeks to identify the onset of the mechanical wave which follows the propagation of the electrical signal through each heartbeat. EWI uses a 1-D cross-correlation algorithm in a 1-D search and a least-squares estimator, on RF data acquired at 2000 Hz. EWI has shown preliminary success in localizing arrhythmia. In a canine MI model, both ME and EWI show success identifying infarcted tissue, and EWI shows potential to have higher specificity when identifying infarcted myocardium in acute MI. In the chronic MI canine model, EWI shows the ability to identify damaged myocardium, even when cumulative ME strain indicates recovery. These results indicate that ME and EWI can provide complementary information for identifying and localizing MI.