Improved sampling of myocardial motion with variable separation tagging.

A novel tagging method is introduced that increases the spatial resolution of estimates of myocardial radial thickening. The separation of adjacent parallel tag planes is customized to match the expected motion of specific regions of the heart wall. In regions in which the tags increase their separation over systole (radial thickening), the tag planes are placed close together at end diastole. In regions in which the tags decrease their separation over systole (circumferential shortening), the tags are placed farther apart so they remain detectable at end systole. With variable separation tagging (VTAG), parallel plane tagging can be used to obtain higher-resolution estimates of radial thickening and circumferential shortening simultaneously.