Skip to main content
Article thumbnail
Location of Repository

Design and evaluation of an RF front-end for 9.4 T human MRI

By Gunamony Shajan, Jens Hoffmann, Juliane Budde, Gregor Adriany, Kamil Ugurbil and Rolf Pohmann

Abstract

At the field strength of 9.4 T, the highest field currently available for human MRI, the wavelength of the MR signals is significantly shorter than the size of the examined structures. Even more than at 7 T, constructive and destructive interferences cause strong inhomogeneities of the B1 field produced by a volume coil, causing shading over large parts of the image. Specialized radio frequency hardware and B1 management methods are required to obtain high-quality images that take full advantage of the high field strength. Here, the design and characteristics of a radio frequency front-end especially developed for proton imaging at 9.4 T are presented. In addition to a 16-channel transceiver array coil, capable of volume transmit mode and independent signal reception, it consists of custom built low noise preamplifiers and TR switches. Destructive interference patterns were eliminated, in virtually the entire brain, using a simple in situ radio frequency phase shimming technique. After mapping the Bmath image profile of each transmit channel, a numerical algorithm was used to calculate the appropriate transmit phase offsets needed to obtain a homogeneous excitation field over a user defined region. Between two and three phase settings are necessary to obtain homogeneous images over the entire brain

Year: 2011
OAI identifier: oai:eprints.gla.ac.uk:122959
Provided by: Enlighten
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://dx.doi.org/10.1002/mrm.... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.