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.
|Haemer, Gillian G; Vaidya, Manushka; Collins, Christopher M et al. (2018) Approaching ultimate intrinsic specific absorption rate in radiofrequency shimming using high-permittivity materials at 7 Tesla. Magn Reson Med 80:391-399|
|Alon, Leeor; Lattanzi, Riccardo; Lakshmanan, Karthik et al. (2018) Transverse slot antennas for high field MRI. Magn Reson Med 80:1233-1242|
|Assländer, Jakob; Glaser, Steffen J; Hennig, Jürgen (2018) Application of spin echoes in the regime of weak dephasing to T1 -mapping of the lung. Magn Reson Med 79:960-967|
|Vaidya, Manushka V; Sodickson, Daniel K; Collins, Christopher M et al. (2018) Disentangling the effects of high permittivity materials on signal optimization and sample noise reduction via ideal current patterns. Magn Reson Med :|
|Paška, Jan; Cloos, Martijn A; Wiggins, Graham C (2018) A rigid, stand-off hybrid dipole, and birdcage coil array for 7 T body imaging. Magn Reson Med 80:822-832|
|Lattanzi, Riccardo; Zhang, Bei; Knoll, Florian et al. (2018) Phase unwinding for dictionary compression with multiple channel transmission in magnetic resonance fingerprinting. Magn Reson Imaging 49:32-38|
|Vaidya, Manushka V; Lazar, Mariana; Deniz, Cem M et al. (2018) Improved detection of fMRI activation in the cerebellum at 7T with dielectric pads extending the imaging region of a commercial head coil. J Magn Reson Imaging 48:431-440|
|Vaidya, Manushka V; Deniz, Cem M; Collins, Christopher M et al. (2018) Manipulating transmit and receive sensitivities of radiofrequency surface coils using shielded and unshielded high-permittivity materials. MAGMA 31:355-366|
|Yu, Zidan; Xin, Xuegang; Collins, Christopher M (2017) Potential for high-permittivity materials to reduce local SAR at a pacemaker lead tip during MRI of the head with a body transmit coil at 3?T. Magn Reson Med 78:383-386|
|Deniz, Cem M; Carluccio, Giuseppe; Collins, Christopher (2017) Parallel transmission RF pulse design with strict temperature constraints. NMR Biomed 30:|
Showing the most recent 10 out of 27 publications