Tracking MR tag surfaces using a spatiotemporal filter and interpolator

Magnetic resonance (MR) tagging is a method for visualizing cardiac motion in MR images by inducing artificial, high-contrast features that move with the tissue. To enable quantitative analysis of tagged MR images, a method f or tracking the movement of tag features is required. In this article, we p resent a new method for tracking the deformation of planar tags applied to the left ventricle of the heart, The method generates a continuous three-di mensional reconstruction of deformed tag planes using optimal estimation th eory. Tag plane movement is modeled as a time update process, where each up date consists of a quadratic component that describes the bulk motion of th e tag planes plus a stochastic component that characterizes the fine-scale variation in the motion. The model is used in conjunction with a novel, rec ursive algorithm that efficiently estimates the deformation of tag planes f rom time-series data. Results are shown using both simulated and actual MR images. (C) 1999 John Wiley & Sons, Inc.