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- 2014
Assessment of subendocardial vs. subepicardial left ventricular twist using tagged MRI imagesAbstract: The heart is composed of oblique myocardial fibers that create a wringing contraction to pump the blood into aorta. Many studies have shown a relationship between dynamic cardiac rotation and cardiac systolic (1-4) and diastolic function (5). A popular way to analyze the cardiac rotation is speckle tracking echocardiography (STE). STE is an image processing method to analyze myocardial deformation, independent of cardiac translation and insonation angle. STE is non-invasive and can be an indicator of cardiac function (6-9). However, 2D STE can only provide 2D motion vectors and suffers from out-of-plane motion error (10,11). Additionally, selection of optimal imaging planes for 2D STE is difficult due to limited acoustic windows and oblique orientation of the heart. Failure to acquire the standard plane can lead to inaccuracy in the measurements. Moreover, measuring the left ventricle (LV) twist using 2D STE needs two apical and basal slices in two different cardiac cycles, which necessitates separate breath-holds and leads to less accurate analysis. Although 3D twist analysis is feasible in echocardiography data (12), echocardiography images are inherently noisy and prone to artifacts; while magnetic resonance imaging (MRI) images can provide us with excellent anatomical resolution. Tagged MRI, in particular, is a method to embed non-invasive tag lines on the cardiac tissue and track it over the cardiac cycle. Motion detection using tagged MRI has been widely used in the literature in order to analyze the cardiac dynamics (13,14)
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