Construction of the Global Lagrangian Strain Field in the Myocardium Using DENSE MRI Data

The main aim of this study is to generate global strain maps within the myocardial wall. Transmural strain calculations are performed using DENSE MRI data, acquired in a long-axis plane for canine subjects over the complete cardiac cycle. Continuum mechanics formulations were applied to all segments of the myocardium and later analyzed from anatomical and physiological perspectives. Characteristic parameters of the myocardial wall – namely global strain distributions – were quantified by means of numerical analyses of DENSE MR data. Our study demonstrated the initiation of myocardial strain as well as heterogeneous contraction patterns across the ventricle wall. There were measurable wall shear strains throughout the cardiac cycle, with the maximum strain within the long-axis plane concentrated in the septal wall at the start of systole and later becoming more pronounced in the lateral wall in the diastolic period. The methods described will lead to a better understanding of the complex myocardial contraction from these space- and time-resolved data on wall motion.