Premium
Increasing signal homogeneity and image quality in abdominal imaging at 3 T with very high permittivity materials
Author(s) -
de Heer P.,
Brink W. M.,
Kooij B. J.,
Webb A. G.
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24438
Subject(s) - image quality , permittivity , dielectric , coefficient of variation , homogeneity (statistics) , nuclear medicine , materials science , mathematics , nuclear magnetic resonance , medicine , biomedical engineering , image (mathematics) , physics , computer science , statistics , optoelectronics , artificial intelligence
The appearance of severe signal drop‐outs in abdominal imaging at 3 T arises primarily from areas of very low B 1 +transmit field in the body, and is problematic in both obese as well as very thin subjects. In this study, we show how thin patient‐friendly pads containing new high permittivity materials can be designed and optimized, and when placed around the subject increase substantially the B 1 +uniformity and the image quality. Results from nine healthy volunteers show that inclusion of these dielectric pads results in statistically significant decreases in the coefficient of variance of the B 1 +field, with stronger and more uniform fields being produced. In addition there are statistically significant decreases in time‐averaged power required for scanning. These differences are present in both quadrature‐mode operation (coefficient of variance decrease, P < 0.0001, mean 25.4 ± 10%: power decrease, P = 0.005, mean 14 ± 14%) and also for the RF‐shimmed case (coefficient of variance decrease, P = 0.01, mean 16 ± 13%: power decrease, P = 0.005, mean 22 ± 11%) of a dual‐transmit system. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.