Magnetic resonance cardiac tagging: visualization of LV function parameters

Magnetic Resonance Imaging (MRI) tissue tagging allows the non-invasive placement of magnetic markers into the myocardium. These tags appear as black lines and remain visible on the myocardium during the cardiac cycle. A semi-automatic segmentation tool is used to delineate the tags. A tagging analysis program calculates from these time-varying tag coordinates several LV functional parameters: e.g. radius of curvature, torsion, and many shear and other strains. For accurate interpretation of the LV function, combining this information is necessary. The authors present two visualization techniques that offer an integrated three-dimensional display of these data, in order to alleviate their inspection: the "Morphological Color-Labeled Surfaces", in which the spatial coordinates of the LV are preserved, and the "3D Polar Maps", which are an extension of the well-known (2D) polar maps or "bull\´s eyes".