Dynamic image reconstruction: MR movies from motion ghosts
โ Scribed by Qing-San Xiang; R. Mark Henkelman
- Book ID
- 102905195
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 759 KB
- Volume
- 2
- Category
- Article
- ISSN
- 1053-1807
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โฆ Synopsis
Abstract
It has been previously shown that an image with motion ghost artifacts can be decomposed into a ghost mask superimposed over a ghostโfree image. The present study demonstrates that the ghost components carry useful dynamic information and should not be discarded. Specifically, ghosts of different orders indicate the intensity and phase of the corresponding harmonics contained in the quasiโperiodically varying spinโdensity distribution. A summation of the ghosts weighted by appropriate temporal phase factors can give a timeโdependent dynamic image that is a movie of the object motion. This dynamic image reconstruction technique does not necessarily require monitoring of the motion and thus is easy to implement and operate. It also has a shorter imaging time than pointโbyโpoint imaging of temporal variation, because the periodic motion is more efficiently sampled with a limited number of harmonics recorded in the motion ghosts. This technique was tested in both moving phantoms and volunteers. It is believed to be useful for dynamic imaging of timeโvarying anatomic structures, such as in the cardiovascular system.
๐ SIMILAR VOLUMES
Data which are sampled more densely than the Nyquist limit in k-space are weighted prior to reconstruction by the inverse of the local sampling density. This work considers the effects of weighting data that are sampled less densely than the Nyquist limit. It specifically analyzes azimuthally unders