This invention is a new method for real time cardiac magnetic resonance (MR) imaging that produces high-spatial and temporal resolution motion movies of the beating heart non-invasively using a MRI scanner, even in the presence of breathing.
MRI's use in the cardiovascular system has been limited. The basic challenge in cardiac MRI is posed by the dynamic motion of the imaged object during the MR data acquisition; unless special methods are adopted this produces unwanted artifacts in the reconstructed MR images in the presence of physiological motion. Also, instead of simply capturing "snap-shot" images one could reconstruct a dynamic movie of the moving object, providing further information of possible diagnostic value.
Methods designed to deal with the motion of objects caused by the beating of the heart and respiration can be classified into three categories: 1) general fast imaging approaches 2) methods dealing with respiration-induces motion 3) methods dealing with cardiac-induced motion This technology improves on the existing methods in several ways.
- Does not require breath holding, and the drawbacks associated with it.
- Acquires data throughout the respiratory cycle and can reconstruct real-time images of a cardiac slice.
- Uses estimates of the respiration-induced motion to select the ideal set of MR data to be acquired and thus reduces the complexity of the reconstruction algorithm while improving the reconstruction quality.
- Uses a more accurate motion model for respiratory motion to produce still and moving images with fewer artifacts and wider applicability.
- Compensates for affine respiration-induce motion exactly. It can also optimize the MR acquisition and reconstruction process and can produce a motion-movie of the dynamically beating heart.
- Does not assume cardiac cyclicity, acquires data throughout the heartbeat and can produce real-time cardiac motion movies.
- Explicitly models the effects of both cardiac and respiration-induced motion effects and hence overcome the drawbacks of these models.
Benefits
- Easy to integrate - This system can be combined with pre-existing static and dynamic MR imaging methods to make them insensitive to affine respiratory motion and tolerant of more general (non-affine) respiratory motion.
- Improved image quality - The quality of dynamic cardiac reconstructions obtainable by MR scanners is improved in current applications by reducing image artifacts. Also improves the MR imaging (MRI) of other organs (such as the liver) whose images are otherwise degraded by respiratory motion Extends clinical applications of cardiac MRI - Improves the spatial and temporal resolution and enables real time 3-D imaging.
- Helps more people - Increases the reach of cardiac MR to a larger set of patients by eliminating constraints imposed by breath-holding requirements.