View Presentation Video

Markus W. May^1,2, Oliver Kraff¹, Jenni Schulz³, Stephan Orzada⁴, Sebastian Schmitter⁵, Thomas Meurs⁶, Mark van Uden⁶, Tom Scheenen³, and Harald H. Quick^1,2
1Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany, ²High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, ³Department of Medical Imaging, Radboud University Medical Center, Nijmegen, Netherlands, ⁴Medical Physics in Radiology (E020), German Cancer Research Center (DKFZ), Heidelberg, Germany, ⁵DZHK (German Center for Cardiovascular Research), DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany, ⁶Tesla Dynamic Coils, Zaltbommel, Netherlands

Keywords: RF Arrays & Systems, Body

The purpose of this study is to compare two different coil array designs for prostate imaging. We compared an in-house developed 8ch^pTx/Rx micro stripline element coil array with meanders to a recently introduced, commercially available 8ch^pTx/Rx coil array based on fractionated dipoles for ¹H prostate imaging at 7T. Both coil arrays showed comparable results in the phantom and in vivo examinations. The commercially available coil array performs slightly better in the region of the prostate and is well suited for future prostate imaging at 7T.

View Presentation Video

Divya Baskaran¹, Paul McElhinney¹, Sydney Williams¹, Sarah Allwood Spiers², David Porter¹, and Shajan Gunamony^1
1Imaging Centre of Excellence, University of Glasgow, Glasgow, Scotland, ²MRI Physics, NHS Greater Glasgow and Clyde, Glasgow, Scotland

Keywords: High-Field MRI, RF Arrays & Systems, Neurovascular imaging

Combined full brain and neck MRI has been proven inevitable in diagnosis of variety of neurodegenerative diseases such as multiple sclerosis, and amyotrophic lateral sclerosis.  High spatial resolution and signal-to-noise ratio provided by the ultra-high field MRI systems (>7T) could be valuable in identification of such subtle morphologies which are not noticeable at standard MRI systems.  Current state-of-the-art requires change of coil for imaging either brain or C-spine or equipped with 16-channel transmission capability. This work presents the design and validation of novel neurovascular transceiver array with 8 channels (industry standard) for combined head and neck imaging at 7T.

View Presentation Video

Alexandre D'Astous¹, Merve Kaptan², Daniel Papp¹, Alice Dabbagh², Jürgen Finsterbusch³, Falk Eippert², Eva Alonso-Ortiz¹, and Julien Cohen-Adad^1,4,5,6
1Neuropoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada, ²Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ³Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ⁴Mila - Quebec AI Institute, Montreal, QC, Canada, ⁵Functional Neuroimaging Unit, Centre de recherche de l'Institut universitaire de gériatrie de Montréal, Montreal, QC, Canada, ⁶Centre de recherche du CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada

Keywords: Shims, Spinal Cord

Spinal cord fMRI is challenging, in part due to B0 inhomogeneities. An EPI, z-shimming signal intensity based approach was implemented to automatically and dynamically shim the spinal cord. The technique was implemented in the open-source Shimming Toolbox. Z-shimming was tested on a healthy participant and showed a 14% increase in signal intensity as well as 19% increase in tSNR. The technique was generalized to allow for the use of any shim coil geometry as well as non-EPI data.

View Presentation Video

Max Joris Hubmann^1,2, Robert Kowal ^2,3, Stephan Orzada⁴, Piet Wagner⁵, Frank Seifert⁵, Oliver Speck^2,3, and Holger Maune^2
1Siemens Healthineers GmbH, Magdeburg, Germany, ²Otto-von-Guericke University, Magdeburg, Germany, ³Research Campus STIMULATE, Magdeburg, Germany, ⁴Deutsches Krebsforschungszentrum Heidelberg, Heidelberg, Germany, ⁵Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

Keywords: Non-Array RF Coils, Antennas & Waveguides, Non-Array RF Coils, Antennas & Waveguides

12 transmission coil designs for 7T head imaging are compared using EM simulations for a large diameter transmit coil. The highest power and SAR efficiency are achieved by loop coils, a passively-fed dipole shows the highest intrinsic decoupling and an IMARS the lowest load dependence. The results provide insight to each element's performance. To make a final decision on a coil element, the array performance must also be evaluated in the futur, as this may differ from the performance of the single element performance. Thus, the decision on a particular transmit element depends on the coil's application and configuration.

View Presentation Video

Parisa Lotfi poshtgol¹, Navid P. Gandji¹, Michael Lanagan², Soo-Han Soon³, Wei Chen³, and Qing X Yang^1
1Center for NMR Research, Departments of Neurosurgery and Radiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States, ²Engineering Science and Mechanics, Pennsylvania State University, state college, PA, United States, ³Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States

Keywords: Non-Array RF Coils, Antennas & Waveguides, High-Field MRI, High dielectric material

We investigated the denoising effect of employing double-loop spiral coil (DLSC) versus the conventional single loop surface coil in the presence of ultrahigh dielectric constant materials (uHDCM). The DLSC confines the conservative E-field distribution between the loops which as a result reduces the E-field in the sample, therefore reduces the noise level. Reduction of conservative E-Field makes the non-conservative E-field more dominant in the sample, which synergistically with the noise reduction allows increasing transmit efficiency and receive sensitivity for MRI application.

View Presentation Video

Jiaxu Li^1,2, Liqiang Zhou³, Bin Liu³, Nan Li^1,4, Zhenhua Shen³, Xiaoliang Zhang⁵, and Ye Li^1,4
1Paul C. Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ²School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China, ³Shanghai United Imaging Healthcare, Shanghai, China, ⁴Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province, Shenzhen, China, ⁵Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States

Keywords: Parallel Transmit & Multiband, Shims

High-field magnetic resonance imaging is one of the main development directions of magnetic resonance cardiac imaging because of its high signal-to-noise ratio and more anatomical details. However, with the increase of field strength, the homogeneity of B1 field is a serious challenge, and parallel transmission is one of the important methods to solve this problem.In this work, we proposed a clinically applicable radiofrequency shimming method to improve the imaging quality of cardiac imaging at 5T MRI.Statistical methods were employed to find out a better initial phase of an eight-channel coil and enhance the stability of cardiac imaging.

View Presentation Video

Thomas Foo¹, Mark Vermilyea¹, Gene Conte¹, Chris Van Epps¹, Justin Ricci¹, Minfeng Xu¹, Anbo Wu¹, Shike Huang¹, Seung-Kyun Lee¹, Wolfgang Stautner¹, Bai Ye¹, Doug Kelley², John Huston III³, Matt A Bernstein³, Yunhong Shu³, Christopher Hess⁴, and Duan Xu^4
1GE Research, Niskayuna, NY, United States, ²GE Healthcare, Waukesh, WI, United States, ³Mayo Clinic, Rochester, MN, United States, ⁴University of California-San Francisco, San Francisco, CA, United States

Keywords: High-Field MRI, Magnets (B0), Cryogenics; Low-Cryogen; Compact

Steps in the construction of an 8 metric ton, 7.0 T MRI scanner for imaging the brain are described. The system nearing completion uses only 12 liters of liquid helium and has outside dimensions comparable to a clinical whole-body 3.0 T scanner, with a similar footprint. As such, the new Compact 7.0 T system fits into any whole-body 3.0 T room, simplifying installation. The system is in the final stages of assembly.

View Presentation Video

Matthijs H.S. de Buck¹, Peter Jezzard¹, and Aaron T. Hess^1
1Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom

Keywords: Parallel Transmit & Multiband, High-Field MRI, B1+ mapping

Acquiring robust multi-channel B1⁺ maps in both the head and neck using pTx head coils at 7T can be challenging due to the combination of low RF penetration into the neck, the limited dynamic range of multi-channel B1⁺ mapping techniques, and B0 sensitivity. We present a pipeline for large dynamic range pTx field mapping along with a publicly available 10-subject database of head and neck field maps for a commonly used multi-channel head transmit coil. The pipeline is evaluated by comparing the predicted B1⁺ to the measured B1⁺ for random transmit shim configurations in the head and neck.

Liyun Zheng^1,2,3, Chun Yang^1,2, Yongming Dai⁴, and Mengsu Zeng^1,2
1Shanghai Institute of Medical Imaging, Shanghai, China, ²Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China, ³Shenzhen United Imaging Research Institute of Innovative Medical Equipment, Shenzhen, China, ⁴MR Collaboration, Central Research Institute, United Imaging Healthcare, Shanghai, China

Keywords: High-Field MRI, Kidney

At high magnetic field strengths (B0 ≥ 3 T), susceptibility-weighted imaging (SWI) is an appealing approach for increased signal-to-noise ratio (SNR). To our knowledge, implementation of SWI on the kidney at higher field MRI (> 3T) has not been attempted yet. This initial study proved that it is possible to obtain SWI at 5T for renal with sufficient image quality. For 5T SWI, SNR of cortex and medulla and CNR of cortex/medulla were significantly higher than at 3T, leading to improved vessel conspicuity and corticomedullary discrimination.

View Presentation Video

Son Chu¹, Vincent Gras², Nicolas Boulant², and Shajan Gunamony^1
1University of Glasgow, Glasgow, United Kingdom, ²University of Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif sur Yvette, France

Keywords: RF Arrays & Systems, RF Arrays & Systems

Transmit arrays are essential to mitigate B₁⁺ inhomogeneity at extremely high static magnetic field strengths. In addition, the transmit elements must be arranged in multiple rows to achieve whole-brain coverage at 11.7T. Furthermore, concurrent field monitoring probes offer the possibility to improve MR image quality by correcting subject-specific k-space trajectories and monitoring real-time dynamic field fluctuations. The placement of these probes must be carefully controlled to achieve proper probe conditioning as well as to preserve the RF performance of the transmit array. This work presents the numerical simulation and optimization of a 16-channel-transmit array with integrated field probes.

View Presentation Video

Christoph Stefan Aigner¹, Jean Pierre Bassenge^1,2, Sebastian Dietrich¹, Max Lutz¹, Felix Krüger¹, and Sebastian Schmitter^1,3,4
1Physikalisch-Technische Bundesanstalt (PTB), Berlin and Braunschweig, Germany, ²Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany, ³Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, ⁴University of Minnesota, Center for Magnetic Resonance Research, Minneapolis, MN, United States

Keywords: RF Pulse Design & Fields, Parallel Transmit & Multiband

3D ultrahigh field (UHF) imaging of the body, particularly the heart, is highly challenging due to the inhomogeneous transmit field (B₁⁺) leading to spatially varying flip-angle (FA) patterns. This study demonstrates that pre-computed universal pulses (UPs) allow for calibration-free 3D cardiac FA homogenization at 7T, despite inter-subject variations because of sex, age, BMI, and coil-placement differences. Furthermore, the performance is robust across multiple MRI operators or re-scans after one year. UPs are, therefore, suited to significantly simplify UHF cardiac imaging by removing the need for lengthy calibration prescans.

View Presentation Video

Tobey D Haluptzok¹, Simon Schmidt¹, Russell L Lagore¹, and Gregory J Metzger^1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

Keywords: RF Arrays & Systems, High-Field MRI

To more fully realize the benefit of UHF MRI, coil designs must be optimized to for pTx and intrinsic SNR performance. In this abstract we compare 5 RF coil array block systems. The first comparison ran is pTx performance, the second comparison is of intrinsic array SNR, and the third tests robustness to top loading. The shielded and unshielded three-loop dipole elements performed better than the single-loop dipole and the shieled helped with top load insensitivity. From these results we conclude that the three-loop dipole coil blocks have superior performance and that the shield doesn’t hurt performance.

View Presentation Video

Redouane Jamil¹, Aurélien Massire², Franck Mauconduit¹, Vincent Gras¹, Mathieu Naudin^3,4,5, Rémy Guillevin^3,4,5, Eberhard Pracht⁶, Tony Stöcker^6,7, Nicolas Boulant¹, and Rüdiger Stirnberg^6
1Paris-Saclay University, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France, ²Siemens Healthcare SAS, Saint-Denis, France, ³CHU Poitiers, Poitiers, France, ⁴LRCOM I3M, DACTIM LMA CNRS 7348, University of Poitiers, Poitiers, France, ⁵Laboratory of Applied Mathematics, UMR CNRS 7348, University of Poitiers, Poitiers, France, ⁶German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany, ⁷Department of Physics and Astronomy, University of Bonn, Bonn, Germany

Keywords: Parallel Transmit & Multiband, Parallel Transmit & Multiband, High-Field MRI; fMRI

Keywords: Parallel Transmit & Multiband; High-Field MRI; RF Pulse Design & Fields; fMRI

PASTeUR is a package of sequences using non-selective parallel transmission Universal Pulses (UP) as a plug-and-play pTX solution alleviating B₁⁺ inhomogeneities. Here, we extend the UP solution to slab-selective excitations while preserving a plug-and-play philosophy. A slab of any thickness/orientation/rotation can be acquired without subject-specific calibrations. In vivo experiments performed with an fMRI protocol on a 3D-EPI show that the improved B₁⁺ homogeneity can result in higher SNR. Moreover, the slab-selective UP coupled with parallel imaging and segmented k-space acquisitions pushed further the quality of 3D-EPI.

View Presentation Video

Xiaoliang Zhang¹, Matt Waks², Lance DelaBarre², Komlan Payne¹, Kamil Ugurbil², and Gregor Adriany^2
1Department of Biomedical Engineering, State University of New York at Buffalo, Buffalo, NY, United States, ²Radiology, University of Minnesota, Minneapolis, MN, United States

Keywords: New Devices, High-Field MRI

A flexible patch array using small-sized 5-cm coaxial transmission line (CTL) resonators is designed, constructed and tested, aiming for human head imaging at the ultrahigh field of 10.5T. Bench tests on decoupling performance among resonant elements are shown. For full utility, a detuning circuit is successfully developed, showing the ecellent detuning capability for 5-cm small CTL loops at 447 MHz. This study suggests that it is possible to build high-density receive-only coil arrays using small-sized CTL resonators at 10.5T.

View Presentation Video

Giuseppe Carluccio^1,2 and Christopher Michael Collins^1,2
1Radiology, NYU Grossman School of Medicine, New York, NY, United States, ²Center for Advanced Imaging Innovation and Research (CAI2R), New York University, New York, NY, United States

Keywords: Non-Array RF Coils, Antennas & Waveguides, Non-Array RF Coils, Antennas & Waveguides, High-Permittivity Materials

High-Permittivity Materials are used in MRI to manipulate the B1 field distribution for example to provide a stronger transmit efficiency. For a given coil, the transmit efficiency depends on the frequency. Here we examine the effects of a high-permittivity helmet on the transmit efficiency in exciting the brain with a birdcage coil over a range of frequencies. The optimal frequency providing the maximum transmit efficiency is not significantly impacted by the presence of the helmet, while the maximum efficiency can increase by about 100% compared to when no helmet is used.

View Presentation Video

Vladislav Koloskov¹, Alena Shchelokova¹, and Andrew Webb^2
1School of Physics and Engineering, ITMO University, St. Petersburg, Russian Federation, ²Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands

Keywords: Hybrid & Novel Systems Technology, Hybrid & Novel Systems Technology, metasurface, passive shimming

We propose a new passive radiofrequency (RF) shimming approach using a flexible, compact, low-cost, and long-term stability metasurface to improve brain imaging at 7T. The metasurface can be manufactured as a periodic structure based on a set of metal crosses connected by the capacitors, thus having a thickness of less than 1 mm. Numerical studies with the human voxel model showed up to 6% homogeneity improvement at the regions of interest (ROI) in the presence of the metasurface in comparison with the conventional case, which also outperforms the effect of the dielectric pad’s placement.