Elimination of transverse coherences in FLASH MRI Export

@article{RFspoiling, abstract = {Fast low-angle shot (FLASH) imaging enables TI-weighted scans to be acquired in a few seconds. However, the diagnostic image quality is severely compromised by the appearance of artifactual bands parallel to the frequency encode direction. We show that the band structure arises from differences in the ability of the phase encode gradient to spoil transverse coherences that build up between successive repetition intervals. A theoretical understanding of the mechanisms involved leads to a comparison between various methods of spoiling the unwanted echoes throughout the whole field of view. Spoiler gradients whose amplitudes change linearly with phase encode step number are treated in detail. The theory predicts that the spoilers will rotate and rescale the band structure and these results are confirmed experimentally. The effect of the spoilers at a given location along the gradient is equivalent to the effect on the entire field of view of an incremented phase shift applied to the radiofrequency pulse. An appropriate rf phase shift scheme should therefore provide ideal spoiling characteristics for FLASH imaging. {\copyright} 1988 Academic Press, Inc.}, address = {Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Toronto, Canada M4X 1K9; Department of Radiation Oncology, New England Medical Center and Tufts University School of Medicine, Boston, Massachusetts 02111}, author = {Crawley, Adrian P. and Wood, Michael L. and Henkelman, Mark R.}, citeulike-article-id = {3208412}, citeulike-linkout-0 = {http://dx.doi.org/10.1002/mrm.1910080303}, citeulike-linkout-1 = {http://www3.interscience.wiley.com/cgi-bin/abstract/112150768/ABSTRACT}, comment = {erkl\"{a}ren rf spoiling theoretisch und zeigen, wie sie die richtung der spoilergradienten varieren. ausgangslage: flash mit t1 hat artefakte entlang der phase encode direction.}, doi = {10.1002/mrm.1910080303}, journal = {Magnetic Resonance in Medicine}, keywords = {1988, classics, mrm, rf-spoiling}, number = {3}, pages = {248--260}, posted-at = {2008-09-09 10:08:49}, priority = {2}, title = {Elimination of transverse coherences in FLASH MRI}, url = {http://dx.doi.org/10.1002/mrm.1910080303}, volume = {8}, year = {1988} }

TY - JOUR ID - RFspoiling L3 - citeulike-article-id:3208412 N2 - Fast low-angle shot (FLASH) imaging enables TI-weighted scans to be acquired in a few seconds. However, the diagnostic image quality is severely compromised by the appearance of artifactual bands parallel to the frequency encode direction. We show that the band structure arises from differences in the ability of the phase encode gradient to spoil transverse coherences that build up between successive repetition intervals. A theoretical understanding of the mechanisms involved leads to a comparison between various methods of spoiling the unwanted echoes throughout the whole field of view. Spoiler gradients whose amplitudes change linearly with phase encode step number are treated in detail. The theory predicts that the spoilers will rotate and rescale the band structure and these results are confirmed experimentally. The effect of the spoilers at a given location along the gradient is equivalent to the effect on the entire field of view of an incremented phase shift applied to the radiofrequency pulse. An appropriate rf phase shift scheme should therefore provide ideal spoiling characteristics for FLASH imaging. © 1988 Academic Press, Inc. IS - 3 JF - Magnetic Resonance in Medicine AD - Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Toronto, Canada M4X 1K9; Department of Radiation Oncology, New England Medical Center and Tufts University School of Medicine, Boston, Massachusetts 02111 EP - 260 TI - Elimination of transverse coherences in FLASH MRI VL - 8 SP - 248 KW - 1988 KW - classics KW - mrm KW - rf-spoiling N1 - erklären rf spoiling theoretisch und zeigen, wie sie die richtung der spoilergradienten varieren. ausgangslage: flash mit t1 hat artefakte entlang der phase encode direction. AU - Crawley, Adrian AU - Wood, Michael AU - Henkelman, Mark PY - 1988/// UR - http://dx.doi.org/10.1002/mrm.1910080303 ER -