The broad objective of this research is to develop effective and efficient methods for suppressing motion artifacts in magnetic resonance imaging (MRI). A k-space time approach is proposed to allow systematic tracking of motion effects during image acquisition and to design effective methods for reducing motion effects in image data.
The specific aims are: 1) Develop accurate motion measurement and correction; 2) Optimize view ordering; 3) Develop integrated methods to reduce effects of one-variable motion; and 4) Develop integrated methods to reduce effects of multi-variable motion. Motion artifacts are the most important factor limiting image quality in many MRI studies including cardiac MRI. Ghosting effects of motion have been fairly successfully suppressed with a combination of techniques, yet suppression of motion blurring continues to be elusive, limiting image resolution. This research develops the navigator strategy to reduce motion blurring. Complex physiological motions are decomposed into the global and local motion. Efficient k-space orbits sensitizing multiple components of the global motion are designed for navigator acquisition. The image effects of the global motion are measured and corrected using navigator echoes. The effects of the local motion are reduced through view ordering and gating. Correction, gating, and view ordering are synergistically integrated into image acquisition, overcoming their individual limitations and combining their individual advantages. This integrated approach will substantially improve both the effectiveness and efficiency of motion suppression in MRI. The developed motion suppression methods will be evaluated in coronary MR angiography for suppressing cardiac motion effects, respiratory motion effects, and both cardiac and respiratory motion effects simultaneously. Successful development of this research will result in motion resistant, high resolution, 3D coronary MR angiography.
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