Comparison between eight- and sixteen-channel TEM transceive arrays for body imaging at 7 T

C. J. Snyder, L. Delabarre, S. Moeller, J. Tian, C. Akgun, P. F. Van De Moortele, P. J. Bolan, K. Ugurbil, J. T. Vaughan, G. J. Metzger

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

Eight- and sixteen-channel transceive stripline/TEM body arrays were compared at 7 T (297 MHz) both in simulation and experiment. Despite previous demonstrations of similar arrays for use in body applications, a quantitative comparison of the two configurations has not been undertaken to date. Results were obtained on a male pelvis for assessing transmit, signal to noise ratio, and parallel imaging performance and to evaluate local power deposition versus transmit B 1 (B 1 +). All measurements and simulations were conducted after performing local B 1 + phase shimming in the region of the prostate. Despite the additional challenges of decoupling immediately adjacent coils, the sixteen-channel array demonstrated improved or nearly equivalent performance to the eight-channel array based on the evaluation criteria. Experimentally, transmit performance and signal to noise ratio were 22% higher for the sixteen-channel array while significantly increased reduction factors were achievable in the left-right direction for parallel imaging. Finite difference time domain simulations demonstrated similar results with respect to transmit and parallel imaging performance, however, a higher transmit efficiency advantage of 33% was predicted. Simulations at both 3 and 7 T verified the expected parallel imaging improvements with increasing field strength and showed that, for a specific B 1 + shimming strategy used, the sixteen-channel array exhibited lower local and global specific absorption rate for a given B 1 +.

Original languageEnglish (US)
Pages (from-to)954-964
Number of pages11
JournalMagnetic resonance in medicine
Volume67
Issue number4
DOIs
StatePublished - Apr 1 2012

Keywords

  • 7 T body imaging
  • 7 tesla
  • SAR
  • TEM coil
  • transmit/receive arrays
  • ultra high field

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