Mapping Internal and Bulk Motion of an Object with Phase Labeling in Magnetic Resonance Imaging

Description:

Current MRI methods for tracking the motion of an object over a relatively long period of time requires the use of precisely defined grid points that may be inexact because of limited image resolution or the size of the element being tracked. Phase contrast velocity mapping generally provides high spatial resolution and simple data processing. However, it is generally unsuitable for motion tracking and prone to error. This invention is a cutting edge Magnetic Resonance Imaging (MRI) technique that provides a method for mapping the internal and bulk motion of a specimen by labeling the phase of the specimen magnetization with a selected spatial function and measuring changes in the phase of the magnetization. The special function is selectable to provide magnetization phase modulation corresponding to displacements in a selected direction such as Cartesian or radial or azimuthal direction. This method and associated apparatus is capable of producing images based on magnetization phase modulation using data from stimulated echoes and anti-echoes. This invention has important applications in, among other areas, cardiac functional imaging and can be used to compute accurate strain maps of the heart.