Quick Search:

uzh logo
Browse by:
bullet
bullet
bullet
bullet

Zurich Open Repository and Archive 

Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-56439

Brunner, D O; Paška, J; Froehlich, J; Pruessmann, K P (2011). Traveling-wave RF shimming and parallel MRI. Magnetic Resonance in Medicine, 66(1):290-300.

[img]Published Version
PDF - Registered users only
2027Kb

Abstract

At sufficiently high Larmor frequencies, traveling electromagnetic waves along a magnet bore can be used for remote magnetic resonance excitation and detection, effectively using the bore as a waveguide. So far, this approach has relied only on the lowest waveguide modes and thus has not supported multiple-channel operation for radiofrequency shimming and parallel imaging. In this work, this limitation is addressed by establishing a larger number of propagating modes and tapping their spatial field diversity with multiple waveguide ports. The number of available modes is increased by loading with dielectric inserts; the ports are implemented by stub and loop couplers at the end of a waveguide extension. The resulting traveling-wave array, operated at 298 MHz in a 7T whole-body magnet, is shown to enable radiofrequency shimming as well as parallel imaging with commonly used acceleration factors. The last part of the study concerns the amount of dielectric loading that is required. For the given Larmor frequency and bore dimensions, it is found that rather few water-filled inserts, occupying ∼5% of the bore cross-section, are sufficient for effective parallel imaging.

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Institute of Biomedical Engineering
DDC:170 Ethics
610 Medicine & health
Language:English
Date:2011
Deposited On:22 Jan 2012 21:20
Last Modified:16 Jan 2014 03:37
Publisher:Wiley-Blackwell
ISSN:0740-3194
Publisher DOI:10.1002/mrm.22817
PubMed ID:21695729
Citations:Web of Science®. Times Cited: 8
Google Scholar™

Users (please log in): suggest update or correction for this item

Repository Staff Only: item control page