| 13:30 | 0520.
 | Toward Densely Populated Dipole Arrays for Human Prostate Imaging at 7T: 8Tx16Rx Coaxial-End Dipole Array Georgiy Alekseevich Solomakha1, Markus May2,3, Oliver Kraff2, Klaus Scheffler1,4, Harald Quick2,3, and Nikolai Ivanovich Avdievich 1
1High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 3High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 4Department for Biomedical Magnetic Resonance, University of Tübingen, Tuebingen, Germany Keywords: RF Arrays & Systems, Body, Dipoles, Arrays, RF-shimming, SNR, SAR Motivation: To improve SNR and the SAR-performance in prostate imaging at 7T using a densely populated coaxial-end dipole array. Goal(s): To numerically optimize and evaluate an 8Tx/16Rx coaxial-end dipole array for prostate imaging at 7T. Approach: Geometry of a coaxial-end element was optimized to minimize peak SAR and improve coverage. In transmission, 16 coaxial-end dipoles were combined into 8 pairs. This further reduced pSAR. 8-element fractionated dipole and stripline arrays were simulated for comparison. Results: Optimized 8Tx/16Rx coaxial-end dipole array improved SNR in prostate compared to all other 8-element arrays. SAR-performance of the developed array was better than that of other dipole arrays. Impact: We demonstrated that densely populated 16-element coaxial-end
dipole array improved SNR in the prostate by at least 10% compared to 8-element
arrays. In addition, combining 16 elements in 8 pairs during transmission
improved SAR-performance in comparison to the 8-channel array. |
| 13:42 | 0521.
 | Reproducibility of tailored and universal non-selective excitation pulses at 7T for human cardiac body imaging: A 3-year and an inter-day study Manuel Fernando Sánchez Alarcón1,2, Sebastian Dietrich1, Jean Pierre Bassenge1,2, Jeanette Schulz-Menger2, Sebastian Schmitter1,3,4, and Christoph Stefan Aigner1
1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany, 2Charité – Universitätsmedizin Berlin, Berlin, Germany, 3Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 4Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States Keywords: RF Pulse Design & Fields, High-Field MRI, Reproducibility, Universal pulse, 7T, pTx Motivation: Addressing the issue of reduced spatial variability in flip angle (FA) patterns in ultra-high field 3D imaging of the human heart for inter-year and inter-day studies, ensuring a high level of reproducibility. Goal(s): Find the correct RF parallel transmission (pTx) excitation scheme that reduces FA spatial variability in 7T 3D imaging of the human heart for long-term and short-term studies. Approach: Default, tailored pulses (TP), and pre-computed universal pulses (UP) were evaluated to optimize FA homogeneity in B1+ datasets across three years. Results: The study highlights UPs' robustness in managing FA variations across subjects and coil placements in 3D body imaging at 7T. Impact: This study confirms pre-computed UPs'
suitability for 7T cardiac flip angle homogenization. Different MRI operators maintained
consistent RF performance across three years and inter-day tests,
with no significative differences in scans at various coil positions for both
tests. |
| 13:54 | 0522.
 | Quantitative Abdominal Sodium MRI Combined with 32-Channel Proton pTx MRI at 7T in a Large Field-of-View Anna K. Scheipers1,2, Stephan Orzada1, Johannes Grimm1,2, Jana Losch1,2, Thomas M. Fiedler1, Armin M. Nagel1,3, Sebastian Schmitter1, Mark E. Ladd1,2,4, and Tanja Platt1
1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3University Hospital Erlangen, Institute of Radiology, Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU), Erlangen, Germany, 4Faculty of Medicine, Heidelberg University, Heidelberg, Germany Keywords: High-Field MRI, Quantitative Imaging, 23Na, Sodium, parallel transmit (pTx), TIAMO, tissue sodium concentration (TSC), 7T whole-body coils, Body, Data Acquisition, High-Field MRI, Hybrid & Novel Systems Technology, Kidney, Liver, Multi-Contrast, Non-Proton, Whole Body Motivation: 23Na MRI enables the quantification of the tissue sodium concentration. A large field-of-view is beneficial for abdominal MRI, especially if several organs are of interest. Due to lower resolution compared to 1H MRI, 23Na MRI is less suited for segmentation. Goal(s): To combine large field-of-view 1H and quantitative abdominal 23Na MRI in the same position at 7T. Approach: Employing a custom-built 23Na radiofrequency coil and reference vial setup together with a 32-channel proton pTx array to allow dual-nuclei MRI in the same position. Results: Combination of large field-of-view 1H and quantitative 23Na MRI of the human torso is feasible at 7T in ≤42min. Impact: This work shows the feasibility of combined 1H and 23Na imaging at 7T in a large field-of-view both under free breathing, laying the ground work for an accurate evaluation of the tissue sodium concentration in several organs at once. |
| 14:06 | 0523.
 | Opening new horizons with the first human brain in vivo experiments at 11.7T Franck Mauconduit1, Vincent Gras1, Alexis Amadon1, Aurelien Massire2, Caroline LeSter1, Denis Le Bihan1, Michel Luong3, Michel Bottlaender4, Alexandre Vignaud1, and Nicolas Boulant1
1University Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-yvette, France, 2Siemens Healthcare SAS, Courbevoie, France, 3IRFU, CEA, Gif-sur-yvette, France, 4University Paris-Saclay, CEA, Uniact, NeuroSpin, Gif-sur-yvette, France Keywords: High-Field MRI, High-Field MRI Motivation: Ultra-high magnetic field MRI offers new opportunities due to its higher SNR and CNR. Goal(s): After receiving the authorization for scanning 20 adult healthy volunteers on the whole-body Iseult MRI scanner, we performed a preliminary MRI investigation to acquire the first brain images at 11.7T. Approach: Using a homemade multi-transmit multi-receive head coil and parallel transmission, 3D anatomical images were acquired with multiple sequences and tissue contrasts at high resolution. Results: In this study, high quality whole brain images acquired at 11.7T on the Iseult MRI scanner are presented for the first time to the MR community. Impact: Showing for the first time in vivo brain images acquired at 11.7T on the
whole-body Iseult MRI scanner, this study reveals first potential and
challenges of such systems to the ultra-high field MR community. |
| 14:18 | 0524.
 | Universal Design of Multiphoton Parallel Transmission (MP-pTx) Pulses for Uniform, High-Flip Angle Excitations John M Drago1,2,3, Bastien Guerin2,3, and Lawrence L Wald2,3,4
1Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Dept. of Radiology, Massachusetts General Hospital, A. A. Martinos Center for Biomedical Imaging, Boston, MA, United States, 4Dept. of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States Keywords: High-Field MRI, Brain Motivation: Contrast in high-field MRI is complicated by the spatially non-uniform transmission profile of birdcage coils. Goal(s): We create “universal” pulses for spatially-uniform excitations using multiphoton parallel transmission (MP-pTx). Approach: MP-pTx operates a $$$B_z$$$ shim array in the kHz range to supplement birdcage excitation. We extend this framework to arbitrary flip angles and a universal design (a population of $$$B_1^+$$$ and $$$\Delta B_0$$$ maps) using spinor-domain, Bloch dynamics representation. Results: Universal MP-pTx pulses have 11.3%, and 16.3% flip angle NRMSE for 90º and 180º pulses played on test subjects not used for training, compared to 24.5% and 25.3% with conventional birdcage. Impact: Universal MP-pTx pulses will allow users to mitigate flip angle inhomogeneity present in the brain at 7 T using precomputed pulses without SAR concerns beyond that of a conventional birdcage transmit coil or subject-specific calculations. |
| 14:30 | 0525.
 | T2 Mapping of the Prostate at 7 Tesla: A Feasibility Study Gabriele Bonanno1,2,3, Bernd Jung3,4, Roland Kreis2,3, Sebastian Schmitter5,6,7, Verena C Obmann3,4, Tobias Kober8,9,10, and Tom Hilbert8,9,10
1Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Bern, Switzerland, Bern, Switzerland, 2Magnetic Resonance Methodology, Institute of Diagnostic and Interventional Neuroradiology, University of Bern, Bern, Switzerland, Bern, Switzerland, 3Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland, Bern, Switzerland, 4Dept. of Diagnostic, Interventional and Pediatric Radiology, Inselspital, Bern University Hospital, Switzerland, Bern, Switzerland, 5Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany, Berlin, Germany, 6Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, Heidelberg, Germany, 7Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, Minneapolis, MN, United States, 8Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland, Lausanne, Switzerland, 9Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, Lausanne, Switzerland, 10LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, Lausanne, Switzerland Keywords: High-Field MRI, Prostate Motivation: T2 relaxometry has shown potential to distinguish cancer from prostate tissue at 3T. Despite potential gains in resolution, it has been little explored at ultra-high field due to challenging B1+ homogeneity and efficiency. Goal(s): To investigate feasibility of prostate T2 mapping at 7T using a robust RF shimming procedure. Approach: We evaluated conventional 2D multi-echo spin echo and an optimized 3D T2-prepared segmented-FLASH sequence. Results: Spin-echo T2 maps showed good quality but required long acquisition times for limited coverage. The T2-prepared FLASH sequence showed similar values while providing higher scan efficiency, lower SAR, and whole-organ coverage at the cost of higher motion sensitivity. Impact: Quantitative T2 mapping at ultra-high field is challenging due to acquisition time and SAR restrictions, especially in the pelvic area. The methods investigated here may be used in future routine to detect and grade prostate cancer. |
| 14:42 | 0526.
 | Motion-robust high-resolution multi-echo 3D gradient echo imaging of the human brain at 10.5 tesla using 80 receive channels Jiaen Liu1,2, Peter van Gelderen3, Jacobus de Zwart3, Jeff Duyn3, Andrea Grant4, Edward Auerbach4, Matt Waks4, Russell Lagore4, Lance Delabarre4, Alireza Sadeghi Tarakameh4, Yigitcan Eryaman4, Gregor Adriany4, Kamil Ugurbil4, and Xiaoping Wu4
1Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, 2Radiology, UT Southwestern Medical Center, Dallas, TX, United States, 3Advanced MRI section, NINDS, NIH, Bethesda, MD, United States, 4CMRR, Radiology, Medical School, University of Minnesota, Minneapolis, MN, United States Keywords: High-Field MRI, High-Field MRI, multi-parametric mapping; motion and field correction Motivation: There is an increasing interest in T2*-related contrast at ultrahigh field for increased signal-to-noise and contrast-to-noise ratios. Goal(s): To demonstrate the feasibility and utility of high-resolution T2*-weighted brain MRI at 10.5 tesla by combining a motion-robust multi-echo gradient-echo method with a high-channel-count RF coil. Approach: Images were collected at 0.5-mm isotropic resolution using a custom 80-channel receive (80Rx) coil and used for quantitative R2* and susceptibility mapping. Results: Our method effectively eliminated artifacts from motion, producing quality images and multi-parametric maps. Parallel imaging performance was improved using the 80Rx coil relative to the commercial 7-tesla Nova 32Rx coil. Impact: The demonstrated feasibility and utility of motion-robust high-resolution multi-echo gradient echo imaging in humans at 10.5 tesla may shed light on future optimal implementation of anatomic T2*-weighted brain MRI at ultrahigh field, paving the way for many neuroscience applications. |
| 14:54 | 0527.
 | Remarkably enhanced B1 and SNR with uHDC ceramics integrated with novel RF transreceiver array for 2H, 17O, and 1H imaging of human brain at 10.5T Soo Han Soon1,2, Matt Waks1, Xin Li1, Hannes M. Wiesner1, Xiao-Hong Zhu1, and Wei Chen1,2
1Center of Magnetic Resonance Research (CMRR), Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 2Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States Keywords: RF Arrays & Systems, Parallel Transmit & Multiband, High Permittivity Material (HPM), ultrahigh Dielectric Constant (uHDC) Material, MRSI, UHF, Ultrahigh field, Broadband RF Coil Motivation: 2H and 17O MRSI are useful to study brain energy metabolism, however, have low imaging sensitivity. Goal(s): To develop a RF coil engineering solution offering superior performance for human brain 1H MRI, 2H and 17O MRSI at UHF. Approach: We constructed a novel RF transreceiver array coil, which can operate at 1H, 2H and 17O resonant frequencies at 10.5T. The integration of ultrahigh dielectric constant (uHDC) ceramics enhanced RF transmission field (B1+) and SNR. Results: The new array coil functioned well for performing multinuclear imaging, and the integrated uHDC technology remarkably enhanced B1+ and SNR for performing 2H and 17O MRSI. Impact: In this study, we introduce and demonstrate an
advanced RF array coil integrated with the uHDC material enabling imaging of
three important nuclei (1H, 2H and 17O) signals with superior performance aiming
for human brain applications at UHF of 10.5T. |
| 15:06 | 0528.
 | Non-idealized system (NIS) optimization of EPI sequences at ultra-high field. Daniel West1, Felix Glang2, Jonathan Endres3, David Leitão1, Sarah McElroy4, Moritz Zaiss2,3,5, Jo Hajnal1,6, and Shaihan Malik1,6
1Biomedical Engineering Department, King's College London, London, United Kingdom, 2Max Planck Institute for Biological Cybernetics, University of Tübingen, Tübingen, Germany, 3Institute of Neuroradiology, Universitätsklinik Erlangen, Erlangen, Germany, 4MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, 5Department of Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, 6Centre for the Developing Brain, King's College London, London, United Kingdom Keywords: System Imperfections, Pulse Sequence Design Motivation: MRI scanners are built under the assumption of near perfect responses of each subsystem. Computing advances mean that this may no longer be necessary, enabling exploration of cheaper, efficient alternatives. Goal(s): To allow high-performance scanning with less emphasis on hardware performance, reducing costs and improving access. Approach: We consider non-idealized system optimization where hardware imperfections are built into a forward model used to optimize pulse sequences via the MR-zero framework. We experimentally demonstrate NIS using measured GIRFs from a 7T system to optimize EPI sequences. Results: NIS optimization produces sequences that substantially reduce image artefacts even for scenarios that previously exceeded hardware constraints. Impact: NIS optimization embraces gradient system imperfections, discovering novel acquisition strategies to inherently mitigate them. Although demonstrated on a state-of-the-art 7T scanner, the concept of including imperfections directly into sequence design offers a means to maximize performance of any scanner hardware. |
| 15:18 | 0529.
 | Design of an Open-transmit / 24-channel flexible receiver head coil for MRI/fMRI of somatosensory and motor cortex at 5T Zidong Wei1,2,3, Zhilin Zhang4, Qiaoyan Chen1,3, Cuiting Wang2, Xiaoliang Zhang5, Xin Liu1,3, Jinglong Wu4, Hairong Zheng1,3, and Ye Li1,3
1Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 2Shanghai United Imaging Healthcare, Shanghai, China, 3Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China, 4Research Center for Medical AI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 5Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States Keywords: High-Field MRI, High-Field MRI Motivation: Functional magnetic resonance imaging (fMRI) is a non-invasive in vivo functional mapping technique, which afforded a high-quality glimpse of the cortex. Goal(s): Sampling brain activity across cortical layers by using proposed RF coil Approach: The Open-Face birdcage coil was designed by removing and adjusting the legs of the 16-rung high-pass birdcage coil. The 24ch flexible receive array was designed for high spatiotemporal-resolution MRI/fMRI at cortical region. Results: In this study, we designed and constructed an open-transmit and 24 channel flexible receiver head coil assembly for human somatosensory and motor cortex in vivo cortical imaging on a whole body 5T scanner. Impact: SNR
maps, T2* weighted images and fMRI images were acquired with the proposed coil assembly,
which were compared with those using a quadrature birdcage transmit/48-channel
receiver coil assembly. |