Local shape adaptation for curved slice selection
| Autor: | Denis Kokorin, Juergen Hennig, Daniel Gallichan, Maxim Zaitsev, Martin Haas, Hans Weber |
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| Rok vydání: | 2013 |
| Předmět: |
business.industry
Acoustics Pulse duration Curvature computer.software_genre Imaging phantom 030218 nuclear medicine & medical imaging 03 medical and health sciences Nonlinear system 0302 clinical medicine Optics Voxel Distortion Encoding (memory) Radiology Nuclear Medicine and imaging business computer 030217 neurology & neurosurgery Excitation Mathematics |
| Zdroj: | Magnetic Resonance in Medicine. 72:112-123 |
| ISSN: | 0740-3194 |
| Popis: | Purpose Nonlinear spatial encoding magnetic fields allow excitation and geometrically matched local encoding of curved slices. However, the nonlinearity of the fields results in a varying slice thickness. Within this study, the technique is combined with multidimensional RF excitation for local adaptation of the slice shape. Theory A framework originally developed for nonlinear receive encoding is applied to multidimensional excitation with nonlinear spatial encoding magnetic fields for determination of dedicated target patterns and combined with a model for assessment of minimum transmit-resolution requirements for the design of efficient transmit k-space trajectories. Methods Cross-sections of curved slices acquired in a phantom with both locally adapted slice thickness and curvature are evaluated. In addition, resulting voxel shapes are analyzed to investigate the range of applicability of the technique. Finally, slice-thickness adaptation is applied to in vivo curved slice imaging. Results Local adaptation of the slice thickness is feasible both in phantom and in vivo. The technique further allows local adaptation of the slice curvature. However, its range of applicability is limited by prolonged pulse duration and voxel shape distortion. Conclusion Multidimensional excitation allows imaging of curved slices with constant thickness. It also has the potential for further modification of the slice shape for increased ability to adapt to the anatomy. Magn Reson Med 72:112–123, 2014. © 2013 Wiley Periodicals, Inc. |
| Databáze: | OpenAIRE |
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