Fast multistation water/fat imaging at 3T using DREAM-based RF shimming

• Published in: Journal of magnetic resonance imaging Vol. 42; no. 1; pp. 217 - 223
• Main Authors: Hooijmans, Melissa T., Dzyubachyk, Oleh, Nehrke, Kay, Koken, Peter, Versluis, Maarten J., Kan, Hermien E., Börnert, Peter
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.07.2015; Wiley Subscription Services, Inc
• Subjects: Adipose Tissue - anatomy & histology; Adipose Tissue - metabolism; Algorithms; Body Water - metabolism; DREAM; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Imaging, Three-Dimensional - methods; Magnetic resonance imaging; Radio Waves; Reproducibility of Results; RF shimming; Sensitivity and Specificity; Whole Body Imaging - methods; whole-body imaging; 3T; RF shimming; whole-body imaging; DREAM
• ISSN: 1053-1807; 1522-2586; 1522-2586
• DOI: 10.1002/jmri.24775

Purpose To show the effect, efficiency, and image quality improvements achievable by Dual Refocusing Echo Acquisition Mode (DREAM)‐based B1+ shimming in whole‐body magnetic resonance imaging (MRI) at 3T using the example of water/fat imaging. Materials and Methods 3D multistation, dual‐echo mDixon gradient echo imaging was performed in 10 healthy subjects on a clinical 3T dual‐transmit MRI system using station‐to‐station adapted B1+ shimming based on fast DREAM B1+ mapping. Whole‐body data were obtained using conventional quadrature excitation and station‐by‐station adapted DREAM‐based B1+ shimmed excitation, along with the corresponding B1+ maps for both excitation modes to assess image quality and radiofrequency (RF) performance. Results Station‐dependent DREAM‐based B1+ shimming showed significantly improved image quality in the stations covering the upper legs, pelvis, and upper body region for all subjects (P < 0.02). This finding is supported by corresponding B1+ maps showing an improved B1+ homogeneity and a more precise flip angle in the DREAM‐based B1+ shimmed excitation (P < 0.01). Furthermore, the very short dual‐channel DREAM B1+ mapping times of less than 2 seconds facilitate quick B1+ shimming. Conclusion Station‐dependent DREAM‐based B1+ shimming improved RF performance and image quality and is therefore a promising technique for whole‐body multistation imaging applications. J. Magn. Reson. Imaging 2015;42:217–223. © 2014 Wiley Periodicals, Inc.