ISMRM25 - Doing More with RF Pulses: PTx & Multiband

ISMRM & ISMRT Annual Meeting & Exhibition • 10-15 May 2025 • Honolulu, Hawai'i

Doing More with RF Pulses: PTx & Multiband

Digital Poster

Physics & Engineering

Wednesday, 14 May 2025

Exhibition Hall

09:15 - 10:15

Session Number: D-192

No CME/CE Credit

		Computer Number: 97 3438. Multiphoton Excitation Enabled Simultaneous Multislice Parallel Transmission at 7T View Presentation Video T. D. Ipek, V. Han, P. Krahn, C. Liu University of California, Berkeley, Berkeley, United States Impact: This work demonstrates the effectiveness of combining Multiphoton SMS with pTx, achieving comparable homogeneity to Full pTx MB while reducing RF power requirements. Multiphoton SMS pTx provides a promising approach for more efficient and safer SMS excitation at ultrahigh fields.
		Computer Number: 98 3439. Fast Gradient Ascent Pulse Engineering for parallel transmission pulse design in the small and large tip angle regimes View Presentation Video N. Dudysheva, J. Brégeat, F. Mauconduit, A. Massire, N. Boulant, V. Gras Université Paris-Saclay, CEA, NeuroSpin, CNRS, BAOBAB, Gif sur Yvette, France Impact: With a flip angle accuracy comparable to GRAPE and a computation time comparable to kT-points, fastGRAPE presents a promising strategy both for online and offline dynamic RF shimming.
		Computer Number: 99 3440. Evaluation of the effects of motion on dynamic pTx pulse optimization at 7T View Presentation Video J. Philippe, N. Pato Montemayor, A. Klauser, E. Sleight, P. A. Liebig, J. Herrler, R. M. Heidemann, T. Kober, J-P Thiran, T. Hilbert, G. F. Piredda, T. Yu Siemens Healthineers International AG, Lausanne, Switzerland Impact: Fast online customized pTx pulses suffer from motion during long scanning sessions, mainly due to changes in B₁⁺ field distribution. However, for motion amplitudes comparable to what was measured, the negative impact on low flip angle non-selective pulses is negligible.
		Computer Number: 100 3441. Switching pTx: Time-Division Multiplexing for Improved kT Points Excitation with a Limited Number of RF Power Amplifiers View Presentation Video F. Glang, G. Solomakha, D. Bosch, K. Scheffler, N. Avdievich Max Planck Institute for Biological Cybernetics, Tübingen, Germany Impact: Time-division multiplexing allows driving a larger number of Tx elements with a smaller number of RFPAs, resulting in improved pTx performance. This opens up new possibilities for using advanced multi-row pTx coils in sites with only 8 RFPAs available.
		Computer Number: 101 3442. SBBMBSpokes: Sequence building block for multiband spokes pTx pulses View Presentation Video M. Zhang, I. Dragonu, C. Rodgers University of Cambridge, Cambridge, United Kingdom Impact: Our scanner software module greatly improves the pTx workflow in 2D imaging. The expanded functionality in multiband, integrated correction for system imperfection, and accelerated sequence preparation allow the use of spokes pTx pulses in routine research or clinical scans.
		Computer Number: 102 3443. Quasi-instantaneous subject-specific slice-by-slice pTx pulse design with Deep Learning: application to 2D diffusion MRI View Presentation Video J. Bartlett, C. Davey, I. Tyshchenko, Y. Blunck, J. Duan, L. Johnston, S. Lévy University of Melbourne, Melbourne, Australia Impact: The proposed deep learning method enables subject and slice-specific pTx pulse design for 2D sequences with a large number of slices in a practical time, providing full brain coverage with improved homogeneity at 7T.
		Computer Number: 103 3444. 10.5T in-vivo head imaging with universal RF shimming View Presentation Video Y. W. Park, S. Schmidt, W. Bogner, G. Metzger, M. Marjańska University of Minnesota, Minneapolis, United States Impact: Simpler and faster acquisition of head structural images at 10.5T using a universal RF shim.
		Computer Number: 104 3445. A Scalable Simulcast X-nuclei MRI System for Concurrent Multi-Frequency Transmit/Receive C. Yang, C. Wu, Z. Zhang, N. Li, Z. Ding, L. Hu, J. Yuan, K. Wang, X. Sun NHC and CAMS Key Laboratory of Molecular Probe and Targeted Theranostics, Molecular Imaging Research Center (MIRC) of Harbin Medical University, Harbin, China Impact: Simultaneous and rapidly interleaved acquisition of signals from ¹H/¹⁹F/²³Na/³¹P were achieved with our Simulcast X-nuclei MRI system, which provides inspiring possibilities for in vivo simultaneously characterizing lesion site structure, molecular targets, ion perturbations and energy metabolism information.
		Computer Number: 105 3446. Accelerated large FOV TSE body imaging at 7T using local contrast optimized AMORE View Presentation Video T. Haluptzok, S. Schmidt, G. Metzger University of Minnesota, Minneapolis, United States Impact: A generalization of the AMORE method, AMORE-C, is developed that enables TSE imaging using a TR half that of standard TSE sequences. This method has minimal SAR penalties and enables large FOV imaging in the body with improved scanning efficiency.
		Computer Number: 106 3447. Individually optimized dynamic parallel transmit pulses for 3D high-resolution SPACE imaging at 7T View Presentation Video G. F. Piredda, E. Sleight, T. Yu, A. Klauser, N. Pato Montemayor, J. Philippe, L. Bacha, T. Di Noto, B. Maréchal, P. Liebig, D. Nickel, T. Kober, T. Hilbert, R. Heidemann, J. Herrler Siemens Healthineers International AG, Lausanne, Switzerland Impact: Individually optimized dynamic parallel transmit pulses for 3D high-resolution SPACE imaging at 7T achieve clinically acceptable image homogeneity and acquisition time, enabling the application of widely used clinical contrasts at 7T.
		Computer Number: 107 3448. Scalable spokes pTx pulses for 2D turbo-spin-echo imaging at 7T View Presentation Video M. Zhang, C. Rodgers University of Cambridge, Cambridge, United Kingdom Impact: Scalable spokes pTx pulses produce high quality 2D-TSE images. It mitigates signal dropouts and recover diagnostic quality when single-transmit scans are inadequate. This will be valuable for patients with drug-resistant focal epilepsy to find epilepsy-causing lesions in the temporal lobes.
		Computer Number: 108 3449. Subpopulation universal pulses: practical online implementation I. Tyshchenko, J. Bartlett, Y. Blunck, B. Tahayori, K. Chow, P. Liebig, L. Johnston, S. Lévy The University of Melbourne, Melbourne, Australia Impact: The novel head clustering and pulse selection pipeline enables subpopulation universal pulses in clinical practice. It enables pulse selection for each head shape and position without extending scan time, facilitating personalized and efficient ultra-high field MRI.
		Computer Number: 109 3450. Improved flip-angle uniformity in 0.35-mm slices using asymmetric pTx spoke pulses View Presentation Video C-Y Wu, J. Polimeni, M. Cloos University of Glasgow, Glasgow, United Kingdom Impact: Parallel transmit is well known for efficient radiofrequency pulse designs that produce uniform excitations. We show that asymmetric spokes can mitigate off-resonance effects and generate uniform excitation for 0.5-mm and 0.35-mm thick slices.
		Computer Number: 110 3451. Deep Learning Based Ultrafast and Robust RF Shimming Using Quadrature B1+ Maps View Presentation Video X. He, B. Yang, X. Zhu, D. Shen, E. Printz, G. Wu, L. Sun, R. Peters GE HealthCare, Waukesha, United States Impact: The deep learning based RF shimming may offer a faster workflow for ultrahigh field imaging, greatly reducing B1+ calibration scan time with less sensitivity to motion and more consistent improvements in image quality.
		Computer Number: 111 3452. GRAPE-based slab-selective universal parallel transmit excitation pulses for whole-brain MRSI at 7 Tesla View Presentation Video Y. Völzke, D. Löwen, E. Pracht, A. Radbruch, B. Strasser, L. Hingerl, G. Hangel, P. Lazen, W. Bogner, T. Stöcker Department of Neuroradiology, University Clinic Bonn, Bonn, Germany Impact: This work shows the feasibility of GRAPE-based frequency-selective universal parallel transmit excitation pulses for whole-brain MRSI. These reduce spatial flip angle variations, and the resulting SNR loss, which is one of the main difficulties in whole-brain MRSI at ultra-high field.
		Computer Number: 112 3453. MRI B1 Optimization using Coupled Coil Modal Analysis View Presentation Video V. Venkidu, M. Raja Viswanath, M. Shokrekhodaei, A. Reykowski, S. King Promaxo Inc., Oakland, United States Impact: This adaptable analytical approach, employing a secondary coil to enhance the TX coil’s B₁ field uniformity and localization, supports improved MRI imaging quality and enables our one-sided MRI system to image deeper into the body.

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