An important trend in MR in recent years has been the move towards higher magnetic field (B0) strengths, which promises to advance disease understanding and diagnosis with enhancements in detection sensitivity, metabolite resolution, imaging speed, and tissue contrast. However there are technical challenges that severely hamper the practice of human high field MR, including a major one that accompanies the creation of MR signal using radio frequency EM fields - B1 and concomitant E fields. As B0 strength increases, the degradation in B1 homogeneity due to increased wave behavior often causes severe image quality issues. Meanwhile E-induced RF heating of the subject body (SAR) poses increasingly inhibiting constraints on the application of high-performance MR sequences. With a great capacity for alleviating the limitations imposed by B1 inhomogeneity and SAR exacerbation, parallel RF transmit is emerging as a key enabling technology for high field MR. This project aims at significantly improving human high field MR capability and safety by creating innovative solutions to spin excitation, RF apparatus, and RF energy deposition in subjects. This will be accomplished with specific efforts on a) developing a much needed non-invasive method for measuring, predicting, and proactively managing SAR, b) leveraging the method in optimizing parallel excitation pulses and in breaking new ground of 7T MR applications, and c) transforming RF hardware and pulse designs to considerably boost high field MR system performance. The successful completion of this project will lead to quantitative / predictive methods that enable the fulfillment of the full potential of in vivo imaging at high field, high impact body imaging applications, and innovative RF methods that promise to bring signal creation and detection performance to a new level.
This project will create a vital RF solution to human high field MR, and will enable the fulfillment of the full potential of high field MR in the detection and diagnosis of diseases.
|Cao, Zhipeng; Park, Joshua; Cho, Zang-Hee et al. (2015) Numerical evaluation of image homogeneity, signal-to-noise ratio, and specific absorption rate for human brain imaging at 1.5, 3, 7, 10.5, and 14T in an 8-channel transmit/receive array. J Magn Reson Imaging 41:1432-9|
|Cao, Zhipeng; Oh, Sukhoon; Otazo, Ricardo et al. (2015) Complex difference constrained compressed sensing reconstruction for accelerated PRF thermometry with application to MRI-induced RF heating. Magn Reson Med 73:1420-31|
|Chang, Gregory; Deniz, Cem M; Honig, Stephen et al. (2014) MRI of the hip at 7T: feasibility of bone microarchitecture, high-resolution cartilage, and clinical imaging. J Magn Reson Imaging 39:1384-93|
|Carluccio, Giuseppe; Collins, Christopher M; Erricolo, Danilo (2014) A fast, analytically based method to optimize local transmit efficiency for a transmit array. Magn Reson Med 71:432-9|
|Alon, Leeor; Deniz, Cem Murat; Brown, Ryan et al. (2013) Method for in situ characterization of radiofrequency heating in parallel transmit MRI. Magn Reson Med 69:1457-65|
|Deniz, Cem Murat; Brown, Ryan; Lattanzi, Riccardo et al. (2013) Maximum efficiency radiofrequency shimming: Theory and initial application for hip imaging at 7 tesla. Magn Reson Med 69:1379-88|
|Deniz, Cem Murat; Alon, Leeor; Brown, Ryan et al. (2012) Specific absorption rate benefits of including measured electric field interactions in parallel excitation pulse design. Magn Reson Med 67:164-74|
|Zhu, Yudong; Alon, Leeor; Deniz, Cem M et al. (2012) System and SAR characterization in parallel RF transmission. Magn Reson Med 67:1367-78|