Oliver Heid¹, Michael Kleemann¹, and Jürgen Heller^1
1CT NTF HTC, Siemens AG, Erlangen, Bavaria, Germany

MRI is attractive as radio therapy guidance and control method due to its soft tissue contrast and its absence of X-ray radiation. We report on a proof of concept of an integrated radio-oncology LINAC treatment machine within an MRI system resulting in a reasonably compact and cost efficient device. Experimental prof is given which demonstrates operating a conventional 6 MeV LINAC within a conventional superconducting high field MRI magnet.

Daniel H Paulus¹, Harald H Quick^1,2, Matthias Fenchel³, Christian Geppert³, David Faul⁴, Yiqiang Zhan⁵, Fernando E Boada^6,7, Kent L Friedman⁶, and Thomas Koesters^6,7
1Institute of Medical Physics, University of Erlangen-Nürnberg, Erlangen, Germany, ²High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, ³Siemens AG Healthcare, Erlangen, Germany, ⁴Siemens AG Healthcare, New York, NY, United States, ⁵Siemens AG Healthcare, Malvern, PN, United States, ⁶NYU Langone Medical Center, Center for Biomedical Imaging, Department of Radiology, New York, NY, United States, ⁷NYU Langone Medical Center, Center for Advanced Imaging Innovation and Research, CAI2R, New York, NY, United States

In whole-body hybrid PET/MR imaging, bone is currently disregarded in attenuation correction. For head imaging, several approaches have been proposed to consider bone, but yet, not assigned to whole-body imaging. A novel attenuation correction approach for hybrid PET/MR imaging is presented and evaluated on 19 patients that combines the routine Dixon-based soft tissue segmentation with model-based bone estimation for whole-body imaging. As a standard of reference, CT images of each patient were non-rigidly registered to the MR images. It is shown that the new method significantly improves the PET quantification in bony tissue, bone lesions, and tissue close to bone.

Johan Overweg¹, Falk Uhlemann¹, Phil Jonas², Thomas Amthor¹, Peter Forthmann², Panu Vesanen³, Tero Virta³, Christopher Busch³, and Kevin Brown^4
1Philips Innovative Technologies, Hamburg, Germany, ²Philips Healthcare, Latham, New York, United States, ³MR therapy, Philips Healthcare, Vantaa, Finland, ⁴Elekta Limited, Crawley, United Kingdom

A concept for a real-time MR-guided radiotherapy system has been industrialized to make it suitable for clinical use.

Adam Farag^1,2 and Jean Theberge^3,4
1Ceresensa Inc, London, Ontario, Canada, ²Western University, London, Ontario, Canada, ³Lawson Health Research Institute, Ontario, Canada,⁴Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada

Positron emission tomography and magnetic resonance imaging systems (PET/MRI) has been recently developed for human imaging, harnessing the powers of morphology and function. Yet, such technology is still in need for complementary tools, such as, dedicated radiofrequency resonators. In this work an approach is presented to optimise a dedicated multi-channels head resonator. The resonator will be used to acquire simultaneously PET/MRI images. Aiming to develop objective diagnostic methods to discriminate unipolar from bipolar using combined serotonin PET, resting state fMRI and blood oxygenation level dependent fMRI.

Florian Wiesinger¹, Anne Menini¹, Sangtae Ahn², Lishui Cheng², Gaspar Delso³, Sandeep Kaushik⁴, Ravindra Manjeshwar², and Dattesh Shanbhag^4
1GE Global Research, Munich, Germany, ²GE Global Research, Niskayuna, NY, United States, ³GE Healthcare, Zurich, Switzerland, ⁴GE Global Research, Bangalore, India

PET/MR is a novel hybrid imaging modality which promises to influence radiology in the near and long-term future. Despite dedicated and focused research efforts, MR-based PET attenuation correction (MR-AC) as required for quantitative PET is still considered challenging; especially when compared to PET/CT. A particular challenge is the correct characterization of bone; i.e. the human tissue with the highest PET attenuation value but which is difficult to capture by MR. Recently a novel zero TE (ZT) based method has been described for fast and reliable bone depiction and segmentation. Here we investigate the feasibility of ZT-based PET attenuation correction (ZT-AC) in the head.

Dattesh D Shanbhag¹, Sandeep S Kaushik¹, Sheshadri Thiruvenkadam¹, Florian Wiesinger², Sangtae Ahn³, Rakesh Mullick⁴, and Ravindra M Manjeshwar^5
1Medical Image Analysis Laboratory, GE Global Research, Bangalore, Karnataka, India, ²Diagnostics & Biomedical Technology Laboratory, GE Global Research, Garching, Bavaria, Germany, ³Functional Imaging Laboratory, GE Global Research, Niskayuna, NY, United States, ⁴Diagnostics & Biomedical Technologies, GE Global Research, Bangalore, Karnataka, India, ⁵X-ray & Functional Imaging, GE Global Research, Niskayuna, NY, United States

Correction of metal implant areas in MRAC map is considered an important unmet need to guarantee accurate and robust MR-based PET-AC. We demonstrate that use of spatially adaptive phase field based approach and anatomy context driven decisioning can help address metal implant related issues in tissue segmentation and consequently result in improved fidelity of PET reconstruction. Overall, the presented method will allow for more robust and accurate MR-AC and accordingly PET quantification in the presence of metallic implants.

Mootaz Eldib^1,2, Niels Oesingmann³, David Faul³, Jason Bini^1,2, Lale Kostakoglu⁴, Karin Knesaurek⁴, and Zahi A. Fayad^1
1TMII, Ichan School of Medicine at Mount Sinai, New York, NY, United States, ²Biomedical Engineering, City College of New York, New York, NY, United States, ³Siemens Healthcare, New York, NY, United States, ⁴Radiology, Ichan School of Medicine at Mount Sinai, New York, NY, United States

Yttrium 90 radio-embolization is a therapeutic procedure that delivers radiation directly to hepatic tumors. Post-procedure PET imaging is a useful tool in detection of shunting to other organs, and in dose calculations and quantification. Both of these applications would suffer from errors due to breathing motion and thus motion correction is critical. In this study an MR-based motion correction approach is developed and implemented using a simultaneous PET/MRI scanner. Phantom and human data are presented.

Jaedu Cho¹, Seunghoon Ha¹, Alex Luk¹, Farouk Nouizi¹, Orhan Nalcioglu¹, Gultekin Gulsen¹, and Ming-Ying Su^1
1Center for Functional Onco-Imaging, University of California Irvine, Irvine, CA, United States

MR/scintimammography (MR/SMM) is a promising high sensitivity and high specificity dual-modality imaging system for the diagnosis of breast cancer. We present a new unilateral breast specific coil and a novel dual-modality interface configuration for MR/scintimammography. The new two channel unilateral coil consisted of a quadrature solenoid coil and a quadrature saddle coil. These two channel coils are specifically designed not only to obtain high sensitivity breast MR imaging, but also to allow simultaneous MR/SMM imaging. The performance of this new system configuration is compared to a commercial breast coil.

Aurelien Destruel¹, Ewald Weber¹, Ivan Hughes¹, Yu Li¹, Feng Liu¹, and Stuart Crozier^1
1School of ITEE, University of Queensland, Brisbane, Queensland, Australia

In this work, a RF transmit volume coil was designed to work in a MRI-Linac. Because of the novelty of this approach and the specific geometry of the magnet, specific constraints had to be accommodated. To ensure the reliability of the design, the behaviour of the coil was modelled in an electromagnetic simulation, and a prototype was built in a mock-up of the magnet. Results converged to show that the homogeneity of the transmit field in the DSV are very uniform.

Mootaz Eldib^1,2, Jason Bini^1,2, Olivier Lairez^1,2, Zahi A Fayad^1,2, and Venkatesh Mani^1,2
1Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States, ²Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, NEW YORK, New York, United States

PET/CT is typically used to evaluate vascular inflammation. An advantage of using PET/MR compared to PET/CT is that it delivers less ionizing radiation. Further reduction in the delivered dose of radiotracers using simultaneous PET/MR can be achieved by matching the duration of the PET acquisition to that of MR (which is generally longer in duration than CT) and thus achieving good image quality. In this study, we evaluate the feasibility of low dose, long duration 18F-FDG PET imaging using a simultaneous PET/MR scanner.

Piotr Obara¹, Andreas Loening¹, Valentina Taviani¹, Andrei Iagaru¹, Brian Hargreaves¹, and Shreyas Vasanawala^1
1Radiology, Stanford Hospital, Stanford, California, United States

Diffusion-weighted (DW), T2-weighted, and gadofosveset-enhanced T1-weighted images from 14 whole body PET-MR exams were assessed by 2 radiologists for presence of malignant disease as well as lesion conspicuity and delineation. Compared to PET-CT, MR showed good sensitivity and specificity on a per-organ basis but only fair specificity on a per-patient basis due to false positive findings in osseous structures. Lesion conspicuity was rated best on DW images, particularly in osseous structures. The relatively lower conspicuity on post-contrast images could have been in part due to suboptimal lesion enhancement with gadofosveset.

Mohammad Mehdi Khalighi¹, Gaspar Delso², Sri-Harsha Maramraju³, Greg Zaharchuk⁴, and Gary Glover^4
1Applied Science Lab, GE Healthcare, Menlo Park, CA, United States, ²Applied Science Lab, GE Healthcare, Zurich, Switzerland, ³PET/MR Engineering, GE Healthcare, Waukesha, WI, United States, ⁴Radiology Dep., Stanford University, Stanford, CA, United States

The MR performance of an investigational hybrid PET/MR system is compared to a comparable wide-bore MR machine. We show that the MR performance is not significantly compromised after PET ring insertion. It is also shown that PET acquisition itself has a very small effect (3% SNR drop). Because of the smaller diameter, the PET/MR body coil SNR is higher and demonstrates 30% increased peak B1+. The only significant tradeoff between PET/MR and a wide-bore MR is the bore size (60cm vs. 70cm).

Panu Vesanen¹, Jukka Tanttu¹, Juha Oila¹, Tiina Näsi¹, Annemaria Halkola¹, Tero Virta¹, Falk Uhlemann², Johan Overweg², and Jarmo Ruohonen^1
1MR Therapy, Philips Healthcare, Vantaa, Finland, ²Philips Innovative Technologies, Hamburg, Germany

In treatment of cancer by conventional radiotherapy, motion of the target and nearby organs limits the accuracy of the treatment delivery. A combined MRI and linear accelerator system (MR-Linac) aims to reduce these inaccuracies by providing image guidance with excellent soft-tissue contrast. In this abstract, MR performance of an industry-built 1.5T MR-Linac prototype was evaluated by comparing the image quality to that obtained with a commercially available 1.5T scanner. Pelvis, abdomen, and head & neck anatomies of 20 healthy volunteers were studied. No significant differences in the image quality or SNR were found.

Mohammad Mehdi Khalighi¹, Gaspar Delso², Sri-Harsha Maramraju³, Michel Tohme³, Gary Glover⁴, and Greg Zaharchuk^4
1Applied Science Lab, GE Healthcare, Menlo Park, CA, United States, ²Applied Science Lab, GE Healthcare, Zurich, Switzerland, ³PET/MR Engineering, GE Healthcare, Waukesha, WI, United States, ⁴Radiology Dep., Stanford University, Stanford, CA, United States

In a functional PET/MR study, temporal resolution of PET images is lower than that of MR due to SNR limitation. Time-of-flight (TOF) reconstruction can be used to increase PET images’ SNR and therefore increase the temporal resolution. Five patients were scanned on an investigational simultaneous TOF-enabled PET/MR scanner and PET images were reconstructed with and without TOF. TOF reconstruction showed an SNR improvement of 5-45% (25±10%) compared to non-TOF reconstruction. With this additional SNR gain, frame durations as short as 30s were possible while preserving reasonable image quality. Such short frames may be used to increase the temporal resolution of dynamic brain studies using simultaneous PET/MR imaging.

Abdullah Al Amin¹, Tanvir Baig², Zhen Yao², and Michael A Martens^2
1Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, Ohio, United States, ²Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States

Ever increasing liquid helium (LHe) price has pushed researchers to design background magnets that could operate in conduction cooling mode. High Tc superconductor e.g. MgB₂ is a promising candidate for conduction cooled magnet. But high strain sensitivity of MgB₂ wire could be a limiting factor in designing a whole body MRI magnet of 1.5T or higher. In this work, strain sensitivity of an optimized 1.5T conduction cooled MgB₂ MRI magnet is numerically studied. The stress and strains behavior of the design shows viability of building such conduction cooled magnet.

Ryan Topfer¹, Kai-Ming Lo², Karl Metzemaekers², Donald Jette², Hoby P. Hetherington³, Piotr Starewicz², and Julien Cohen-Adad^1,4
1Institute of Biomedical Engineering, Ecole Polytechnique de Montréal, Montreal, QC, Canada, ²Resonance Research Inc., Billerica, MA, United States,³Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States, ⁴Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montreal, QC, Canada

A novel shim system is introduced for the purpose of real-time shimming in spinal imaging to compensate for respiratory-related distortions of the main field. The 24 independent, rectangular planar shim coils are embedded within the patient bed table, in close proximity to the spine of the scanned subject. Preliminary calibration and “proof of concept” phantom experiments are described. Compared to the unshimmed case, the standard deviation of the field inhomogeneity, as calculated over 1.1 L volumes of interest, was reduced by over 30 %.

Muhammad E H Chowdhury¹, Karen J Mullinger^1,2, and Richard Bowtell^1
1SPMIC, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, ²BUIC, School of Psychology, University of Birmingham, Birmingham, United Kingdom

EEG data recorded during fMRI are compromised by large gradient artefact (GA) voltages. The GA is usually corrected using average artefact correction; requiring the amplifier to have a large enough dynamic range to characterise the artefact voltages. Here we re-designed the EEG cap-cable configuration so that the GA induced in the 1 m ribbon cable by an AP gradient partially cancels that induced in the EEG cap and head. We demonstrate that the range and amplitude of the GA can be significantly reduced by cap-cable re-wiring, allowing recording at higher EEG bandwidths or increased achievable image resolution without saturation.

Huijun Yu¹, Frank Huethe², Sebastian Littin¹, Kelvin Layton¹, Stefan Kroboth¹, Feng Jia¹, Jürgen Hennig¹, and Maxim Zaitsev^1
1Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, BW, Germany, ²Dept. of Clinical Neurology and Neurophysiology, University of Freiburg, Freiburg, BW, Germany

An updated multi-channel switching circuit for matrix gradient coil is presented in this work to reduce the total number of gradient amplifiers and provide more flexibility to generate the customized current patterns. The bridge switches and interconnection switches are used to dynamically configure the current path of coil elements during the pulse sequence to generate the specific current pattern. The amplifier selection switches are used for dynamically defining different channels of the current path during the experiment (the number of channels of current path is equal to the number of used gradient power amplifiers).

Roberto Salvati^1,2, Eric Hitti^1,2, Jean-Jacques Bellanger^1,2, Herve Saint-Jalmes^1,2, and Giulio Gambarota^1,2
1Université de Rennes 1, LTSI, Rennes, France, ²INSERM, UMR 1099, Rennes, France

Virtual Phantom (ViP) for Magnetic Resonance Imaging (MRI) is a method to generate reference signals, without using physical objects, using an external waveform generator and an RF coil. In a previous work it was shown that ViP MRI could substitute agar gel phantoms, using magnitude images. The aim of the current study was to test the feasibility of the ViP MRI method to generate magnitude and phase images that mimic water-fat systems. To this aim, multi gradient-echo magnitude and phase images of ViPs and physical phantoms were acquired for IDEAL (Iterative Decomposition with Echo Asymmetry and Least squares estimation) reconstruction.

Vahid Ghodrati¹, Niloufar Zakariaei¹, and Abbas Nasiraei Moghaddam^1,2
1BME, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Tehran, Iran, ²School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran

Foreign objects with high conductivity can intensify and concentrate the induced eddy currents from the gradient switching. These concentrated currents in turn may cause PNS during MR-imaging and potentially result in a mild to intolerable discomfort for the patient especially when the foreign object is in the vicinity of sensible locations. The maximum limit for applied gradient intensity in different gradient switching times has been modified to guarantee the safe mode in the presence of metallic objects. We showed that the conductive materials mostly affect the small rise times as the modifies limit is less sensitive to gradient rise time compared to IEC standard.

Ying-Hua Chu¹, Yi-Cheng Hsu¹, Shang-Yueh Tsai², Wen-Jui Kuo³, and Fa-Hsuan Lin^1
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, ²National Chengchi University, Taipei, Taiwan, ³National Yang Ming University, Taipei, Taiwan

Here we develop a 10-channel field probe system using 1H as the NMR signal source to monitor the magnetic field. The field probe is decoupled from the subject by interleaving the field probe measurement and subject imaging. Specifically, field probe NMR signal was measured at high spatial frequency k-space point in order to minimize the NMR signal from the subject. Empirical data showed successful monitoring of respiratory and cardiac cycles. We can track 2D field drifting with 0.1 s temporal resolution and use this information to improve the time-domain SNR (tSNR) of dynamic spiral imaging by 137 %.

Simone Angela Winkler¹, Trevor P Wade², Andrew Alejski², Charles McKenzie², and Brian K Rutt^1
1Dept. of Radiology, Stanford University, Stanford, CA, United States, ²Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada

We present a comprehensive modeling approach for acoustic noise in MR gradient coils that includes previously neglected but essential factors. Our simulation environment is the most complete developed to date for vibroacoustic gradient coil simulations, incorporating such features as full structural-acoustic coupling. We have used this new simulation environment to model realistic head and body gradient coils, and have used experimental measurements to demonstrate accurate prediction of acoustic and vibration spectra and spectrally averaged levels. This new simulation environment has great potential for the accurate prediction and ultimately reduction of acoustic and vibration levels in high performance gradient systems.

Elliot Smith¹, Fabio Freschi^1,2, Maurizio Repetto², and Stuart Crozier^1
1School of ITEE, University of Queensland, Brisbane, Queensland, Australia, ²Department of Energy, Politecnico di Torino, Torino, Italy

The thermal performance of MRI hardware is critical to the safe and efficient operation of these devices. Placement of cooling pipes can help to transport heat away from the system. Placing this pipes algorithmically can lead to an efficient cooling system based on thermal simulation and path finding algoithms.

Feng Jia¹, Sebastian Littin¹, Kelvin Layton¹, Stefan Kroboth¹, Huijun Yu¹, Jürgen Hennig¹, and Maxim Zaitsev^1
1Dept. of Radiology, University Medical Center Freiburg, Freiburg, BW, Germany

Zhichao Chen^1,2, Mahdi Abbasi¹, Klaus Solbach², Daniel Erni¹, and Andreas Rennings^1
1General and Theoretical Electrical Engineering (ATE), Faculty of Engineering, University of Duisburg-Essen, Duisburg, NRW, Germany, ²High Frequency Engineering (HFT), Faculty of Engineering, University of Duisburg-Essen, Duisburg, NRW, Germany

A dipole coil with miniaturized eigen-resonant shielding plate at 300 MHz is presented. The size reduction is done by etching several slots in the shielding plate and enclosing the slotted sections with high-dielectric substrates. The dipole element with proposed slotted shielding plate exhibits an improvement in terms of B1 homogeneity and penetration depth comparing to the ordinary (unslotted) case. Single element and multi-channel setups loaded by a homogeneous phantom are utilized to evaluate the proposed approach. Without diminishing the merit of eigen-resonant shielding plate, the presented dipole coil has more placement flexibility for certain applications due to the size reduction.

Johanna Schöpfer^1,2, Klaus Huber², Stephan Biber³, Markus Vester³, Sebastian Martius², and Martin Vossiek^1
1LHFT, University of Erlangen-Nuremberg, Erlangen, Germany, ²Siemens AG, Corporate Technology, Erlangen, Germany, ³Siemens AG, Healthcare, Erlangen, Germany

High SAR values can increase imaging time, especially if very high B1+ fields are required. In this study, potential benefits of inductively coupled planar loop antennas, designed to focus the transmit field, are evaluated and compared to the transmit characteristics of the body coil. It shows that the inserted loop leads to reduced power requirements and SAR without significantly decreasing B1+ homogeneity in the defined ROI, relative to standard excitation with the body coil.

Emer Hughes¹, Tobias Winchmann², Laurent Mager³, Francesco Padormo⁴, Hutter Jana⁴, Julia Wurie¹, Matthew Fox¹, Maryanne Sharma¹, David Edwards¹, Andrew Kapetanakis¹, Alessandro Allievi⁵, and Joseph Hajnal^4
1Centre for the developing brain, Kings College London, London, London, United Kingdom, ²Rapid biomedical engineering, Germany, ³Peraltec AG, Switzerland, ⁴Division of imaging science and biomedical engineering, Kings College London, London, London, United Kingdom, ⁵Imperial College London, London, United Kingdom

Optimal performance for neonatal brain imaging requires the receive coil to be as close fitting as possible, but this creates challenges for patient handling. Here, we developed a joint design of a 32 channel neonatal array and a baby transport and positioning system intended for examining babies up to 44 weeks at time of scan. The purpose of this was to implement a system to consistently gain high image quality in preparation for the developing Human Connectome Project (dHCP).

R. Adam Horch^1,2 and John C Gore^1,2
1Department of Radiology & Radiological Sciences, Vanderbilt University, Nashville, TN, United States, ²Vanderbilt University Institute of Imaging Science, Nashville, TN, United States

An apparatus capable of high precision (< 1 ppb) measurements of magnetic susceptibility has been developed with broad potential in the characterization of materials for MR instrumentation. Measurements of 3D-printed materials relevant to RF coil construction have been performed. For example, 3D-printed ultem differs in susceptibility from water, despite pure ultem’s excellent match. Poly(methyl methacrylate) and polycarbonate-based 3D-printed materials offer alternatives which closely match water’s magnetic susceptibility.

Markus V. Meissner¹, Nils Spengler¹, Dario Mager¹, Jens Höfflin¹, Peter T. While¹, and Jan G. Korvink^1
1Department of Microsystems Engineering - IMTEK, University of Freiburg, Freiburg, BW, Germany

We introduce a novel micro-electroplating process based on ink-jet printed conductive structures, to define high-aspect-ratio MRI field coils. To structure electrically conductive tracks, silver nano particle based ink is printed directly on permanent dry film resist. In this process, molds for electroplating are patterned into thick-film photo-definable resist via backside exposure where our printed structures serve as both the shadow mask for the mold, and the seed layer for the electroplating. Our process is particularly suitable for the rapid manufacture of small planar TxRx, shim and gradient coils.

Thomas Riemer^1
1Insitute for Medical Physics and Biophysics, University of Leipzig, Leipzig, Saxony, Germany

Platzhalter

Sebastian Martius¹, Johanna Schöpfer^1,2, Andreas Fackelmeier¹, and Klaus Huber^1
1Siemens AG, Coporate Technology, Erlangen, Germany, ²LHFT, University of Erlangen-Nuremberg, Erlangen, Germany

Loop antenna arrays are the major components for reception in magnetic resonance imaging systems. Typically 3D full wave field calculation software is used for calculation of the corresponding s-Parameters and field distribution of these loop antennas. In the following paper different simulation methods are compared, including various meshing techniques in time and frequency domain simulations, regarding their suitability of accurately calculating a more complex antenna structure.

Graham C Wiggins^1,2, Karthik Lakshmanan^1,2, and Gang Chen^1,3
1The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, Newyork, NY, United States, ²The Center for Advanced Imaging Innovation and Research (CAI2R),Department of Radiology, New York University School of Medicine, Newyork, NY, United States, ³The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, Newyork, NY, United States

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Kuan Zhang¹, Lian Xue¹, Guangfu Xu², Zungang Liu², Erzhen Gao², Q.Y. Ma², Nikolaus M Szeverenyi³, and Graeme Bydder^3
1Time Medical Systems, Inc, San Diego, CA, United States, ²Time Medical Systems, Inc, China, ³University of California, San Diego, CA, United States

A cyrogenic solenoid transmit/receive coil resonating at 132 MHz for sodium MRI (11.7T) was constructed and tested at liquid nitrogen temperature. The tuning circuit is kept outside the cryostat at room temperature for easy access. The resonant frequency was tunable over a 250 kHz range, allowing compensation for various sample loadings. Images were acquired on a 3 mm thick anatomical human patella specimen using a Bruker 11.7T animal MRI scanner, both with this cryo-coil and a room temperature coil of identical structure for comparison. A 70% SNR improvement was obtained. The coil package is small and convenient for commercial use.

Rui Liu¹, Wei Luo², Thomas Neuberger^3,4, and Michael Lanagan^1,2
1Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States, ²Material Research Insititute, Pennsylvania State University, University Park, Pennsylvania, United States, ³Huck Institute of Life Science, Pennsylvania State University, University Park, Pennsylvania, United States, ⁴Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, United States

In this study, different coupling methods for a cylindrical dielectric resonator operating in TE01δ mode were investigated and compared at 14T. The best coupling method was selected based on the analysis of the scattering parameters. It yielded a Q-factor around 716.2 and S21 value of -9.20 dB. The relationship between different Q-factors and their effects on S21 were discussed. The results from this study will be useful for the new designs on MRI probe head made of cylindrical dielectric resonators.

ChristopherM. M. Collins^1,2, Giuseppe Carluccio^1,2, Manushka Vaidya^1,2, Gillian Haemer^1,2, Riccardo Lattanzi^1,2, Graham C. Wiggins^1,2, Daniel K. Sodickson^1,2, and Qing X. Yang^3
1Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, NY, United States, ²Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, United States, ³Center for NMR Research, Penn State College of Medicine, Hershey, PA, United States

While most work with high permittivity materials (HPMs) in MRI has been focused on improving SNR or transmit efficiency for a relatively small region within a much larger coil or array, more recent work demonstrates that HPMs can also improve performance of smaller coils very near the subject, as well as arrays of such coils for the entire region of the anatomy they encompass. Here we illustrate differences in the nature of coil functionality when HPMs are present with graphical plots and analysis of both conduction currents and displacement currents.

Gillian G Haemer^1,2, Manushka V Vaidya^1,2, Christopher M Collins^1,2, and Graham C Wiggins^1
1The Center for Advanced Imaging Innovation and Research, and the Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, ²The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States

The use of high permittivity materials (HPMs) can improve coil performance at ultra high field. Much recent experimental work performed with HPMs has been done with prefabricated coils and/or standardized clinical coils, built without the use of dielectric materials in mind. However, close-fitting transmit arrays are at risk of interacting closely with the HPM, and therefore having their performance in the presence of the HPM affected. Here we explore how HPMs proximal to a set of three geometrically decoupled coils affect their performance and decoupling.

Gillian G Haemer^1,2, Manushka V Vaidya^1,2, Christopher M Collins^1,2, Daniel K Sodickson^1,2, Graham C Wiggins¹, and Riccardo Lattanzi^1,2
1The Center for Advanced Imaging Innovation and Research, and the Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, ²The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States

Appropriate high-permittivity, low-conductivity materials (HPM) placed between the RF coil and the sample can provide performance improvement in both transmission and reception. We employed a simulation framework based on dyadic Green’s functions for multi-layered spherical geometries to analyze how HPMs affect the tradeoff between excitation homogeneity and global Specific Absorption Rate (SAR) for RF shimming at 7T, using transmit arrays with an increasing number of elements and Ultimate Intrinsic SAR as a reference. We generated L-curves showing ultimate performance could be approached with a relatively small number of transmit elements by optimizing the relative permittivity of the HPM layer.

Aurelien Destruel¹, Jin Jin¹, Feng Liu¹, Mingyan Li¹, Ewald Weber¹, and Stuart Crozier^1
1School of ITEE, University of Queensland, Brisbane, Queensland, Australia

This study presents a novel method of improving dielectric shimming. In contrast to conventional approach where large pads are generally used, narrow segmented pads are used in the current study. Additionally, the combination of permittivity values for all segments is optimised. The simulation results show that, for 7T head imaging, using eight narrow pads with optimised permittivity distribution constraints the displacement currents to the longitudinal direction, to most effectively produce transmit magnetic field. Furthermore, the uniformity of the transmit magnetic field has been significantly improved. By increasing the degrees-of-freedom in regulating the displacement current distribution, the proposed approach provides a new perspective in dielectric shimming.

Gianluigi Tiberi^1,2, Nunzia Fontana³, Riccardo Stara⁴, Alessandra Retico⁵, Agostino Monorchio³, and Michela Tosetti^2
1Imago7, Pisa, PI, Italy, ²IRCCS Stella Maris, Pisa, PI, Italy, ³Dipartimento di Ingegneria dell’Informazione, Pisa, PI, Italy, ⁴Dipartimento di Fisica, Pisa, PI, Italy, ⁵Istituto Nazionale di Fisica Nucleare, sezione di Pisa, Pisa, PI, Italy

A procedure for evaluating RF electromagnetic fields in anatomical human models for any matching and coupling conditions is introduced. The procedure resorts to the extraction of basis functions: such basis functions, which represent the fields produced by each individual port without any residual coupling, are derived through an algebraic procedure which uses the S parameter matrix and the fields calculated in one (only) full-wave simulation. The basis functions are then used as building-blocks for calculating the fields for any other S parameter matrix.

Wyger Brink¹, Yacine Noureddine², Oliver Kraff², Andreas K. Bitz^2,3, and Andrew Webb^1
1Radiology, Leiden University Medical Center, Leiden, Netherlands, ²Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, ³Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany

Electric near-field measurements confirm that the electric fields within the phantom are very well be affected by the dielectric pads. The data presented here indicate an agreement between simulations and measurements of electric and magnetic fields in the order of ~10%. This means that realistic scenarios can be evaluated with this error margin to provide SAR estimates for using pads in vivo.

Manushka V Vaidya^1,2, Gillian G Haemer^1,2, Giuseppe Carluccio¹, Dmitry Novikov^1,2, Daniel K. Sodickson^1,2, Christopher M. Collins^1,2, Graham C. Wiggins^1,2, and Riccardo Lattanzi^1,2
1Center for Advanced Imaging Innovation and Research, and Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, ²Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States

Ideal current patterns maximize the SNR for a position within the imaging sample. Our work demonstrates that in imaging a central voxel, addition of a dielectric layer surrounding a spherical sample results primarily in a phase lag in the ideal current patterns corresponding to the additional propagation time through the layer. For an off-center voxel, the ideal current pattern covers a larger area when the dielectric layer is present, indicating that larger sized coils are optimal in this case. Our results provide an understanding of electromagnetic field behavior with dielectric materials, and provide a method to predict optimal coil design.

Atefeh Kordzadeh¹ and Nicola DeZanche^2
1Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada, ²Department of Medical Physics, Cross Cancer Institute and University of Alberta, Edmonton, Alberta, Canada

Dielectric pads are used as an effective method to increase the signal locally and also increase the RF field homogeneity in high-field MRI. Here we investigate the effect of dielectric liners of various permittivities on the transmit performance of a head coil array at 4.7T. Results show that field homogeneity and sensitivity are competing goals and a compromise is needed based on the application. An optimal value for permittivity is found which is lower than values which are commonly used in the literature.

Xiaoqing Hu¹, Chunlai Li², Hongyi Wang¹, Xiaoliang Zhang³, Xin Liu¹, Hairong Zheng¹, Lin Luan², and Ye Li^1
1Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology of Chinese Academy of Sciences, Shenzhen, Guangdong, China, ²ShenzhenKey Laboratory of Optical and Terahertz Meta-RF, Kuang-Chi Institute of Advanced Technology, Shenzhen, Guangdong, China, ³Department of Radiology and Biomedical Imaging, University of California San Francisco, CA, United States

Influence of metamaterial insert to cylindrical RF coil array in human knee MR imaging at 1.5T

Hideo Sato-Akaba¹ and Hiroshi Hirata^2
1Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan, ²Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan

EPR imaging allows visualizing free radicals in small animals and gives information of redox status in various tissues. However, the determination of the position is difficult due to the lack of anatomical information. So far to solve this problem, co-registration of an EPR image and a high field MRI image has been applied. However, the cost of the high field MRI system may be obstacle for many researchers to access this method. The purpose of the present work was developing a compact low field MRI system running on a same magnetic circuit used for a 750 MHz EPR imaging system.

Alexander Squires¹, John Oshinski², Jason Lamanna², and Zion Tsz Ho Tse^1
1College of Engineering, The University of Georgia, Athens, GA, United States, ²Department of Radiology, Emory University, Atlanta, GA, United States

A MRI-guided needle positioning system was developed to provide a less invasive surgical method for delivering cellular therapeutics to the spinal cord of swine subjects used in ALS studies. The resulting system is capable of delivering 2mm targeting accuracy along with ease of use, the ability to perform multiple injections without repositioning the targeting device, and delivered a physical end product which is disposable to facilitate ease of implementation in further research.

Jennifer Michelle Taylor^1,2, Shan Hu³, Rajesh Rajamani⁴, Xiao-Hong Zhu², Yi Zhang², and Wei Chen^1,2
1Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States, ²Radiology, University of Minnesota, Minneapolis, MN, United States,³Mechanical Engineering, Iowa State University, Ames, IA, United States, ⁴Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States

The use of simultaneous neuronal recording and MRI is limited by artifacts induced both in the imaging and in the neuronal traces, but would provide a huge benefit to the exploration of brain mechanisms and understanding of the neurophysiology basis of fMRI. Here we have developed new electrodes using conductive, non-metal materials that produce no susceptibility artifacts in anatomical or functional imaging. Additionally, we show that the gradient induced artifacts in the neuronal trace are removable, revealing clean neuronal activity. These breakthroughs will allow for future experiments and studies exploring the neurovascular relationship between fMRI and neuronal activity.

Limin Li¹ and Alice M. Wyrwicz^1,2
1Center for Basic MR Research, NorthShore University HealthSystem, Evanston, IL, United States, ²Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States

Jinfeng Tian¹, Russell Lagore², and J. Thomas Vaughan^2
1Center for Magnetic Resonance Research, U. of Minnesota, Minneapolis, Minnesota, United States, ²U. of Minnesota, Minnesota, United States

Dipole Array was proved to be a feasible RF coil for 7T body MRI, and has the potential to meet the RF challenges at 450MHz. With Finite Difference Time Domain method, a 8-ch head dipole array was studied at 300MHz and 450MHz to explore its feasibility for head MRI at 450MHz. Results show while the |B1+| magnitude on the central transverse slice gets worse from 300MHz to 450MHz, the |B1+| uniformity does not deteriorate with frequency. Dipole is a promising RF coil candidate for 10.5T Head MRI and thus deserves further study.

Seunghoon Ha¹, Haoqin Zhu¹, and Labros Petropoulos^1
1R&D, IMRIS Inc., Minnetonka, MN, United States

An asymmetric distributed capacitor capacitance loop array structure that generated highly homogenous B1 field for 7T MRI was presented. The calculated B1 field uniformity and coil sensitivity of the proposed coil was superior to the identical size loop array with symmetrically distributed capacitance as well as the stripline array coil with the same length. The volume shaped array loop coil assembly, consisting of the proposed asymmetric distributed capacitance coil design loops, was confirmed both through testing as well as confirmed our approach through B1+ field simulation study. Also, the proposed design will potentially help the construction of larger size loop arrays to cover more imaging volume at very high fields and obtain uniform coverage and high sensitivity.

Xinqiang Yan^1,2, Xiaoliang Zhang³, Long Wei², and Rong Xue^1
1State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, Beijing, China, ²Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, Beijing, China,³Department of Radiology and Biomedical Imaging, University of California San Francisco and UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, California, United States

Dipole antenna arrays have been applied for ultrahigh field MRI to obtain better SNR gain at the deep area of human tissues. However, there is no suitable decoupling methods proposed for dipole coil arrays in MRI. In this study, we investigated the possibility and performance of magnetic wall (MW) decoupling technique in dipole array designs. A two-channel MW decoupled dipole array was designed, constructed and analyzed experimentally. Both the bench test and experimental results indicate that the MW decoupling is a promising solution to reducing the electromagnetic coupling of dipole arrays, consequently improving their performance in SNR and parallel imaging.

Chathura Kumaragamage^1,2 and Jamie Near^2,3
1Biomedical Engineering, McGill University, Montreal, Quebec, Canada, ²The Douglas Brain Imaging Centre, Montreal, Quebec, Canada, ³McGill University, Montreal, Quebec, Canada

The efficacy of receiver coils decoupling, using clamping diodes on the Tx-line is investigated. We found that signal transmission (S21) is degraded due to impedance mismatching at high frequencies, when simple cross diode shunting is used along the Tx-Line (~8% power loss at 600MHz). A cross diode topology with an added tank circuit was found to improve S21 (~2% power loss at 600MHz). The modified cross diode topology provides an efficient solution for passive decoupling at high-frequencies that is remote to the coil, thus providing a convenient and safe alternative to passive decoupling networks mounted on the receiver coil element.

Xueming Cao¹, Elmar Fischer¹, Boris Keil², Lawrence L Wald^2,3, Jan G Korvink⁴, Jürgen Hennig¹, and Maxim Zaitsev^1
1University Medical Center Freiburg, Freiburg, Germany, ²A. A. Martinos Center for Biomedical Imaging, Dpt. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, ³Harvard Medical School, Boston, MA, United States, ⁴IMTEK, University of Freiburg, Freiburg, Germany

As coil arrays have increasing number of channels, coil element continues to shrink. Therefore the noise originating from coil matching-networks should be considered explicitly. Here,we calculate the matching-network noise and define the concept of a matching-network noise dominating regime, which is a similar concept to the sample noise dominating regime. A criterion determining when the matching-network noise dominates is also formulated in the abstract.

M.J. van Uden¹, A. Rijpma^2,3, C.T. Rodgers⁴, Bart Philips¹, T.W.J. Scheenen¹, and A. Heerschap^1
1Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, Gelderland, Netherlands, ²Department of Geriatric Medicine, Radboud University Medical Center, Gelderland, Netherlands, ³Radboud Alzheimer Center, Radboud University Medical Center, Gelderland, Netherlands,⁴OCMR, RDM Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom

³¹P MRSI provides valuable information on metabolism in neurological diseases such as Alzheimer and brain tumors, but suffers from a relatively low SNR. We present an 8-channel receive array insert in a ³¹P/¹H send birdcage coil for improved ³¹P MRSI of the brain. For the addition of the array coil signals we compared the Time-Domain and Whitened Singular Value Decomposition methods and observed a better SNR for the latter method. This method together with the improved head array insert resulted in about a 4–fold increase in the SNR of the ³¹P MR spectra compared to the birdcage coil.

M. Arcan Erturk¹, Alexander J. E. Raaijmakers², Gregor Adriany¹, Jinfeng Tian¹, Pierre-Francois van de Moortele¹, Cornelis A. T. van den Berg², Dennis W. J. Klomp², J. Thomas Vaughan¹, Kamil Ugurbil¹, and Gregory J Metzger^1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States, ²Imaging Division, UMC Utrecht, Utrecht, Netherlands

MRI of the body/prostate at 7T is challenging due to electromagnetic-field effects. Using a multi-channel transmitter coil is necessary to focus the B1-fields at the target region to improve efficiency. There are several 7T multi-channel external surface-arrays, however a direct experimental comparison between these does not exist. Here, we compare the transmit/receive performance of 16-channel stripline (16SA) and 10-channel dipole-antenna (10DA) arrays on prostates of several subjects. Results show that, 16SA performs better in smaller subjects and targets closer to surface; and 10DA is more favorable in larger subjects, deeper targets and if a more uniform excitation profile is desired.

Pu-Yeh Wu¹, Ying-Hua Chu¹, Shang-Yueh Tsai², Wen-Jui Kuo³, and Fa-Hsuan Lin^1
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, ²Institute of Applied Physics, National Chengchi University, Taipei, Taiwan,³Institute of Neuroscience, National Yang Ming University, Taipei, Taiwan

We developed a 24-channel coil array for human brain temporal lobe imaging. Specifically, we used 12 pairs of quadrature surface coil to optimize the SNR around the auditory cortex. Compared to two overlapped circular loops, quadrature coil pair can improve the SNR by 22%. Anatomical images acquired from our array show detailed brain structure of the temporal lobe. Compared to a 32-channel head coil array, our array shows SNR advantage at region no deeper than 5 cm from the scalp. Functional MRI measurements using our array show strong hemodynamic responses at the auditory cortex elicited by music.

Jhy-Neng Tasso Yeh¹ and Fa-Hsuan Lin^1
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan

For the multi-channels phased-array coils, overlapping is commonly-used as a decoupling technique for loop-type RF coils, but it not only imposes a new spatial criterion but also limit the flexibility degree on flexible application. Here we propose the idea of annex-overlapping instead of traditional loop-overlapping, apply the concept of Koch first-order fractal-shape to deform the simple circular loop with additional outstretching annexes. The MRI image results of our prototypes of three-elements PA coils on a flexible plastic sheet all demonstrated the ability of simultaneous decoupling and flexibility against deformation, provided the potential for mechanically adjustable applications.

Paul T. Weavers¹, Jacob N. Gloe¹, Eric G. Stinson¹, Phillip J. Rossman¹, Thomas C. Hulshizer¹, and Stephen J. Riederer^1
1Radiology, Mayo Clinic, Rochester, Minnesota, United States

Dynamic contrast enhanced MRI (DCE-MRI) of the prostate has been shown to be a useful tool to detect and stage prostate cancer. Increasing parallel imaging acceleration will allow for better pharmacokinetic parameter estimation. Due to various acquisition constraints, the phase encode plane is typically misaligned with best supported plane for parallel imaging. Specialized receiver coils to support parallel imaging in this sub-optimal alignment have been developed and demonstrated.

Victor Taracila¹ and Fraser Robb^1
1General Electric, Aurora, Ohio, United States

Most of the literature on signal reception in magnetic resonance treats the reception mechanism utilizing the reciprocity theorem, according to which the receive sensitivity of the channels can be assessed through the transmit sensitivity of the same very array. In modern MRI receive phased array there are additional circuits attaches to the antennas, so that intuitively is difficult to follow the receive path through the reciprocity theory standpoint. We propose a direct method of deriving the receive sensitivity which we find more intuitive for MRI coil signal characterization, directly applicable when describing additional circuitry attached to the multichannel phased array.

Hui Han¹, John Stager¹, Wei Cao², Miguel Navarro³, Fraser Robb³, Junghun Cho¹, Nozomi Nishimura⁴, Chris Schaffer⁴, Valerie Reyna¹, Yi Wang¹, and Wen-Ming Luh^1
1Cornell MRI Facility, Cornell University, Ithaca, New York, United States, ²Tongji Hospital, Huazhong University of Science and Technology, Hubei, China,³GE Healthcare, Ohio, United States, ⁴Biomedical Engineering, Cornell University, Ithaca, New York, United States

Here we show a homemade 8-ch mouse phased array interfaced to a standard 3T human scanner. A fact one may easily neglect is that the small imaging space allows for an excellent parallel imaging ability even for a low coil-element count (8) being used, which is a different scenario for a human coil with a larger imaging space. An initial trial, using single-shot gradient echo EPI with parameters tailored to fMRI, shows the possibility for functional studies of mice models. To our best knowledge, this is one of few first demonstrations to attempt fMRI of mice on a clinical system.

Madhwesha Rao¹, Fraser Robb^1,2, and Jim Wild^1
1University of Sheffield, Sheffield, South Yorkshire, United Kingdom, ²GE Healthcare, Aurora, Ohio, United States

¹H MRI is emerging as a viable modality for lung parenchyma imaging. However, ¹H lung-MR methods have inherently low signal-to-noise ratio (SNR) in the parenchyma due to the lower ¹H density (<0.2g/cc) and short T₂^*. Thus there are obvious gains to be made through anatomically customized radio-frequency (RF) receiver coil designs. In this work we propose a receiver RF coil array topology designed for high SNR imaging of the lung-cardiac anatomy at 1.5T and illustrate the ¹H SNR improvement over a conventional 8 channel ladder-like topology used routinely for cardio-thoracic MRI.

A.M. Flynn¹, J.R. Corea¹, P.B. Lechene¹, P.D. Calderon², T. Zhang³, G.C. Scott³, S.S. Vasanawala⁴, A.C. Arias¹, and M. Lustig^1
1EECS, Univ. of California, Berkeley, CA, United States, ²Diamant Engineering, Castro Valley, CA, United States, ³EECS, Stanford Univ., Palo Alto, CA, United States, ⁴Radiology, Stanford LPCH, Palo Alto, CA, United States

We have developed a system of flexible coils which can be wrapped closely around a newborn. Because newborns are often inserted into coils which do not fit well, SNR is typically worse than it could be. We have printed flexible coils and packaged them in pairs which can be attached arbitrarily to a swaddled infant. Swaddling naturally provides comfort to a baby. A snug fit will help restrict motion, recoup SNR and enable acceleration, hopefully one day alleviating the need to sedate small children who cannot stay still through an MRI exam.

Azma Mareyam¹, Jonathan R Polimeni^1,2, Allison Stevens¹, Andre Van Der Kouwe^1,2, Loren D Bridgers³, Jason P Stockmann^1,2, Matthew D Tisdall^1,2, Lee Tirrell¹, Allison L Moreau¹, Ani Varjabedian¹, Brian L Edlow^1,2, Bruce Fischl^1,4, and Lawrence L Wald^1,2
1A.A. Martinos Center of Biomedical Engineering, Department of Radiology, Charlestown, MA, United States, ²Harvard Medical School, Boston, MA, United States, ³Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States, ⁴CSAIL, Massachusetts Institute of Technology, Cambridge, MA, United States

We present an integrated system for 7T ex vivo imaging that meets several of the challenging design requirements needed to image a whole ex vivo brain at 100um isotropic resolution in 25 hours of averaging time. It incorporates a 31 channel receive array, an improved mechanical design, preamps mounted at the coil detectors, and an extended transmit coil design capable of producing high-power pulses. This new design substantially increases the range of ex vivo imaging applications.

Alexander J.E. Raaijmakers¹, Arcan Erturk², Greg Metzger², Cornelis A.T. van den Berg¹, and Gregor Adriany^2
1Imaging Division, UMC Utrecht, Utrecht, Utrecht, Netherlands, ²Center for Magnetic Resonance Research, Minneapolis, Minnesota, United States

We explored a dipole antenna design optimized for high B1 sensitivity/efficiency in the prostate while accepting increased SAR levels. Ten 20 cm dipole antennas have been constructed with T-shaped antenna legs. SAR levels were assessed by numerical simulations. This array was compared to an array of fractionated dipole antennas by SNR and B1+ measurements in the prostate and T2w TSE images. As expected, both B1 and SAR levels are higher for the short dipoles. The B1+/√SARmax ratio is 11.3% smaller and the SNR is 10% larger for the short dipole array. Image quality of the short dipoles is generally good.

Yukio Kaneko¹, Yoshihisa Soutome^1,2, Kosuke Ito², Masahiro Takizawa², Hideta Habara^1,2, Yusuke Seki¹, Tetsuhiko Takahashi², Yoshitaka Bito², and Hisaaki Ochi^1
1Central Research Laboratory, Hitachi Ltd., Kokubunji-shi, Tokyo, Japan, ²Hitachi Medical Corporation, Kashiwa, Chiba, Japan

The B1 inhomogeneity in a human body increases as the strength of a static magnetic field increases. Previous studies showed the effect of the number of RF transmit channels in RF shimming. However, the effect for a partial region of the shoulder in 3T has not yet been investigated. In this study, numerical simulation was used to investigate the effect of the number of RF transmit channels for regional RF shimming in the shoulder region in 3T. The results show that 4-channel RF shimming can contribute to improve the B1 homogeneity and reduce the transmit RF power more than 2-channel RF shimming.

Gang Chen^1,2, Karthik Lakshmanan¹, Daniel Sodickson¹, and Graham Wiggins^1
1Center for Advanced Imaging Innovation and Research (CAI2R) and Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, ²The Sackler Institute of Graduate Biomedical Science, New York University School of Medicine, New York, NY, United States

At 7T the combination of loops and electric dipole antennas can provide higher central SNR in a body sized object than is possible with loop coils alone. An array of dipoles has been demonstrated for head imaging, and was shown to provide extended coverage in z compared to a standard birdcage, but suffered from low central SNR compared to loop-based coils. We investigate the addition of a loop array to the previously constructed dipole array. The dipole array is used for transmit and receive to explore the benefits of combining loops and dipoles for increased SNR in 7T head imaging.

Stephan Orzada¹, Andreas K. Bitz², Klaus Solbach³, and Mark E. Ladd^1,2
1Erwin L. Hahn Institute for MRI, Essen, NRW, Germany, ²Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, ³RF Technology, University Duisburg-Essen, Duisburg, Germany

Local Tx/Rx arrays for body imaging at ultra-high field are often bulky and consume much of the limited space inside the bore of the magnet. One option to allow patients with larger body physique and to enable a more clinic-like workflow is to implement an integrated Tx/Rx body coil situated between the gradient coil and the inner lining of the scanner bore. In this work, a receive chain add-on that allows implementation of an integrated 32-channel Tx/Rx body coil to be used together with local receive arrays was successfully developed. The add-on is configured such that normal operation of the system including measurement of X-nuclei is feasible.

Shailesh B. Raval¹, Tiejun Zhao², Narayanan Krishnamurthy¹, Yujuan Zhao¹, Sossena Wood¹, Kyongtae Bae¹, and Tamer S. Ibrahim^1
1University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ²Siemens Medical Solutions, Pittsburgh, Pennsylvania, United States

Body imaging exams are increasingly growing as a part of total clinical MRI exams at lower field (<=3T) and should translate towards UHF imaging because of its excellent promises. Thus, there is a critical need to investigate advancing MR body imaging (kidney, liver and pancreatic) at 7T. The goal of this study is to introduce a new 32-ch Tx array design that; similar to head coils, is capable of producing bright centers inside the torso at 7T using its CP mode.

Bart L. van de Bank¹, Frits Smits¹, Miriam W. van de Stadt-Lagemaat¹, and Tom W.J. Scheenen^1,2
1Departement of Radiology and Nuclear Medicine, Radboud university medical center, Nijmegen, Netherlands, ²Erwin L. Hahn Institute, University Duisburg-Essen, Germany

Separating transmission and reception of signals can significantly boost SNR of ³¹P signals, therefore we developed a 7-channel ³¹P receive-only array that could be used with a detunable ³¹P birdcage, which was inserted into an 8-channel ¹H head-coil. Signals could be enhanced further by exploiting the Nuclear Overhauser Effect as was shown in-vivo.

Saeed Javidmehr¹, Adam Maunder², Mojgan Daneshmand¹, and Nicola De Zanche^3
1Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, ²Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada, ³Oncology, University of Alberta, Edmonton, Alberta, Canada

The emerging technology of 3D printing is expanding into the electronics industry and is replacing traditional fabrication methods for a variety of products with significantly lower costs and labour. In this study, microstrip resonator coils are 3D-printed with built-in matching and tuning capacitors using various dielectric and conductive materials. Our 3D printed partially air-filled MTL resonators show comparable performance to standard hand-made foam-core resonators using copper conductors and discrete capacitors.

Dmitri Artemov¹ and Yoshinori Kato^1,2
1Radiology, Johns Hopkins University, Baltimore, MD, United States, ²3 Life Science Tokyo Advanced Research Center, Hoshi University, Tokyo, Shinagawa-ku, Japan

MR-detectable devices are important for interventional procedures, and should provide a clear imaging signature while not degrading diagnostic imaging quality. A new MR-detectable probe design is presented, based on excitation of MR signals by high-frequency RF harmonics generated by the probe with a non-linear element. The implantable probe was designed to excite MR signals when driven by an external RF filed at half-resonance frequency. A second harmonic at the resonance frequency was generated by a non-linear diode element. MR signals in the subject were excited only in close proximity to the probe and could be detected by a standard receiver coil.

Ziyuan Fu¹, Mark Bolding², and Shumin Wang^1
1Auburn University, Auburn, AL, United States, ²Radiology, University of Alabama, Birmingham, AL, United States

Myung-Kyun Woo¹, Suk-Min Hong², Jongho Lee¹, Young-Bo Kim³, and Zang-Hee Cho^4
1Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea, ²Institute of Neuroscience and Medicine - 4, Forschungszentrum Jüilich, Jülich, Germany, ³Gil Hospital, Incheon, Korea, ⁴Neuroscience Research Institute, Incheon, Korea

Many RF coils have been developed to solve field non-umiformity at ultra-high field. Recently, radiative antenna type with poynting vector has been proposed at UHF. This abstract is to evaluate newly developed radiative antenna type coil, Extended Monopole antenna Array with individual Shields (EMAS) coil at 7T. To analyze, we calculated simulated B1+ field and specific absorption rate (SAR) with Monopole antenna Array (MA), Extended Monopole antenna Array (EMA), and EMAS coils. Then the simulated results were compared with the experimental results. The EMAS coil successfully extended the spatial coverage with uniform B1+ field distribution.

Andreas Pfrommer¹ and Anke Henning^1,2
1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, ²Institute for Biomedical Engineering, UZH and ETH Zurich, Zurich, Switzerland

Parallel imaging with a finite number of array elements is limited by the g-factor enhancement for high k-space undersampling. To fully exploit the unfolding potential of circular surface coils surrounding a spherical head phantom, we developed an optimization routine to minimize the maximum value of the g-factor inside the “head” region. As a result we showed optimal arrangements for 8, 16 and 32 channels at 9.4 T with different acceleration rates. Moreover we precisely specified the range of possible g_max values for each setup including optimal and worst case positioning of the loops.

Arjan D. Hendriks¹, Michel G.M. Italiaander², Natalia Petridou¹, and Dennis W.J. Klomp^1,2
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ²MR Coils B.V., Drunen, Netherlands

Recent developments in high-density surface receiver arrays, together with high BOLD sensitivity at 7T, allow human fMRI at ~0.5mm isotropic resolution and a volume acquisition time in the order of few seconds. However, with element sizes of 1x2cm and 32-channels, these benefits are limited to a small field of view. In this study, the expected g-factor gain of a 256-channel surface coil is estimated by combining 8 measurements of a high-density 32 channel surface coil. Results show that benefits achieved with 32-channels can extend to 256-channels. Full head coverage and decreased g-factors (gain in SNR or acceleration) can be achieved.

Alexander Beckett^1,2, Liyong Chen^1,2, An T Vu³, and David A Feinberg^1,2
1Helens Wills Neuroscience Institute, University of California, Berkeley, CA, United States, ²Advanced MRI Technology, Sebastopol, CA, United States,³CMRR, University of Minnesota, Minneapolis, MN, United States

Advances in imaging hardware and pulse sequences have led increasingly finer resolution imaging at ultra-high fields. We propose to use a novel half shell 20 channel coil designed for optimized imaging in neocortical regions superficial and closest to the coil array rather than deeper brain regions, and demonstrate the advantages of such a coil over a standard 32-channel array in terms of raw signal and tSNR at 0.75 mm and 0.55 mm isotropic resolution. We demonstrate fMRI imaging at 0.75 mm. New coil designs will allow even higher resolutions in future cortical imaging studies with maximal SNR.

John C Nouls¹, Alexandra Badea¹, Gary P Cofer¹, and G Allan Johnson^1
1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States

Diffusion-tensor imaging of mouse brains, used in conjunction with population atlases and statistical methods, can detect subtle pathologies. The total scan time can be prohibitive. We present a parallel acquisition, four-coil system increasing diffusion-tensor imaging throughput in a small bore, 7T scanner. The geometry of the coil system and its shielding has been optimized to preserve SNR, enabling a decrease in imaging time per specimen of 63%. The fractional anisotropy measurement bias due to off-center imaging was 9%. Bringing each coil slightly closer to the magnet isocenter may further decrease imaging time towards the maximum 75% reduction achievable.

M. Arcan Erturk¹, Gregor Adriany¹, and Gregory J Metzger^1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States

In prostate MRI at 7T, use of endorectal coils (ERCs) can improve the signal-to-noise ratio (SNR) more than 4-fold compared to using an external surface array (ESA). Here, we compare the SNR and transmit performance (B1+) of three different 2-channel ERC coil geometries (two loops, ERC-2OL; stripline-large loop, ERC-SLL; stripline-small loop, ERC-SSL) inside a uniform torso-sized phantom. ERC-SSL performed the best among the ERCs. SNR and B1+ of ERC-SSL compared to a 16-channel ESA has improved ~5.6-fold and ~6.9-fold, respectively. Reusable, rigid, multi-channel ERCs are a valuable tool in imaging the prostate at 7T.

Xinqiang Yan^1,2, Long Wei², Rong Xue¹, and Xiaoliang Zhang^3
1State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, Beijing, China, ²Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, Beijing, China,³Department of Radiology and Biomedical Imaging, University of California San Francisco and UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, California, United States

Compared with regular single-row transceiver coil arrays, multiple-row arrays exhibit larger imaging coverage and the capability of parallel imaging and parallel excitation along z-direction. The main challenge in designing multiple-row microstrip array is to attain sufficiently decoupling among coil elements from adjacent rows. In this study, a novel decoupling technique was proposed to address this problem. Both the bench test and MR imaging results demonstrate that the proposed technique could reduce the strong coupling (-7.9 dB) between microstrip elements from adjacent rows to a sufficiently small value (-25.3 dB).

Pei-Shan Wei^1,2, Mike J. Smith², Christopher P. Bidinosti³, and Scott B. King^1,2
1Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada, ²National Research Council of Canada, Winnipeg, Manitoba, Canada, ³Department of Physics, University of Winnipeg, Winnipeg, Manitoba, Canada

Local SAR minimization is of particular importance for Tx-array MRI. We hypothesize that high local hot spots in excitation artifacts are partially due to strong asymmetries in B1+ fields of individual array elements of a Tx-array, which are more prominent at higher B0 fields. We show that modifications to the individual array element geometries, that improve both B1+ symmetry and reduce local B1+ hot spots, resulted in reduced hot spots in excitation artifact, in our case by 25%. Such Tx-array design strategies can improve performance of pTx MRI and may lower local SAR hot spots relative to traditional Tx-array designs.

Sigrun Goluch^1,2, Andre Kuehne^1,2, Albrecht Ingo Schmid^1,2, Ewald Moser^1,2, and Elmar Laistler^1,2
1MR Center of Excellence, Medical University of Vienna, Vienna, Austria, ²Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria

This abstract presents the development of a 3 channel ³¹P and 2 channel ¹H RF coil array for phosphorous spectroscopy in the human visual cortex at 7 T. The naturally low sensitivity of 31P spectroscopy requires very efficient RF hardware for a successful implementation of an experiment. The array was modeled and optimized with the help of 3D electromagnetic simulation and was build and tested on the bench with a network analyzer. Preliminary results were obtained inside the scanner (Siemens, ) with phantom and fruit measurements, showing good results.

Yun-Jie Li¹, Meng-Chi Hsieh¹, In-Tsang Lin², Xiao-Liang Zhang³, and Jyh-Horng Chen^1,4
1Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, Taiwan, ²Xiamen University, Xiamen, Fujian, China, ³Department of Radiology and Biomedical imaging, University of California, University of California, California, United States, ⁴Dept. of Electrical engineering, National Taiwan University, Taipei, Taiwan, Taiwan

This is the development of high-temperature superconducting array coil,and we apply it on the rat spinal cord DTI

Zhoujian Li¹, Roberta Kriegl^2,3, Elmar Laistler^2,3, Marie Poirier-Quinot¹, Luc Darrasse¹, and Jean-Christophe Ginefri^1
1Laboratoire d’Imagerie par Résonance Magnétique Médicale et Multi-Modalités (IR4M), UMR8081 CNRS, Université Paris-Sud, Orsay, France, ²Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, ³MR Centre of Excellence, Medical University of Vienna, Vienna, Austria

A shielding ring based decoupling technique was investigated for small monolithic HTS coils, an analytical model based on magnetic flux compensation to determine the geometric configuration of two neighbor shielding rings to achieve optimal decoupling was developed and validated experimentally using a two-MTLR copper array, and the effect of the shielding rings on the overall coil losses was evaluated using a standard 2-coil array cooled at LN2 temperature. Results show that configuration achieving near-optimal decoupling can be obtained using this model, and high Q-factor value by employing HTS material can be expected by exploiting this technique.

Emilee Minalga¹, Robb Merrill¹, Dennis L Parker¹, Allison Payne¹, and J. Rock Hadley^1
1UCAIR, University of Utah, Salt Lake City, UT, United States

This abstract describes an improvement on a previously designed system for breast magnetic resonance guide focused ultrasound treatments. Results include a signal to noise comparison. The improved design give better signal to noise ratio throughout the treatment volume.

Daniel Papoti¹, Cecil Chern-Chyi Yen¹, Pascal Sati¹, Joseph Robert Guy¹, Daniel S Reich¹, and Afonso C. Silva^1
1NINDS, National Institutes of Health, Bethesda, Maryland, United States

In this work we describe the development and comparison of three different 8-channel receive-only arrays built to provide whole brain MRI coverage of marmosets with high sensitivity. Among all coils built, the design based on a central elliptical element partially overlapped with 7 loops showed excellent coverage with high sensitivity throughout the whole brain. A gain up to 60% in SNR in the frontal cortex, 40% in the occipital cortex, and 20% in the center of the brain was achieved when compared to the other two geometries. High-resolution brain images obtained from an autoimmune encephalomyelitis animal clearly show white matter lesions in both T1- and T2-weighted images.

Nikolai I Avdievich¹, Ioannis A Giapitzakis¹, and Anke Henning^1,2
1Max Planck Institute for Biological Cybernetics, Tübingen, Germany, ²Institute for Biomedical Engineering, UZH and ETH Zurich, Zurich, Switzerland

Ultra-high field (>7T) RF coil design is challenging due to decreased transmit efficiency and strongly distorted B1 field profile. For functional SI of the visual cortex open RF coils are highly suitable since they provide an easy access and increased transmit efficiency by focusing RF field. In this work we demonstrated that a 9.4T 5-channel array with asymmetric arrangement of 4 transmit and 4 receive elements improves the transmit profile without compromising the reception. We also evaluated changes in the transmit efficiency, penetration depth and SAR due to variation in the array size and the phase shift between the elements.

Amin Nazaran¹, Joshua D Kaggie^2,3, Meredith Taylor¹, Daniel J Park¹, Grayson Tarbox¹, Rexford D Newbould⁴, Neal Bangerter¹, and Glen Morrell^3
1Electrical and Computer Engineering, Brigham Young University, Provo, Utah, United States, ²Physics, University of Utah, Salt Lake City, Utah, United States, ³Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, United States, ⁴Imanova Centre for Imaging Sciences, London, United Kingdom

In this abstract, we compared a new phased array sodium breast coil with a single channel sodium coil. The new phased array coil consists of 7 sodium loops that are overlapped to minimize coupling to adjacent sodium loops. The coil used for comparison has a single transmit/receive 1 H loop and a single transmit/receive 23Na loop. The benefits of our new coil include larger volume coverage, and higher SNR (2-3x) than the single channel coil near the surface loops.

Wen-Yang Chiang¹ and Mary P McDougall^1
1Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States

Mechanical stability is crucial in geometric decoupling, especially for small-form-factor wire array coils because the dimensional tolerance is less forgiving. To this end, we incorporated 3D printing to streamline the development of our mouse array coil when solid wire was used. When the solid wire and the PCB were embedded inside of the 3D printed former, we were also able to not only place the array coil as close to the specimen as possible, but also able to maintain the geometric decoupling overtime. Because no glue was used, we could replace any coil components easily. SNR of phantom images acquired by the proposed mouse array coil and by a commercial Varian quadrature mouse birdcage coil were compared. We also quantitatively compared the consistency of the coil sensitivity of each array coil element.

Wolfgang Loew¹, Yu Li¹, Ron Pratt¹, Jean Tkach¹, Charles Dumoulin¹, and Randy O Giaquinto^1
1Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States

A compact 10-channel receive array for neonatal abdomen and chest MRI was developed to enable parallel imaging on a small-footprint 1.5 Tesla superconducting NICU MR-system. The development of the receive array also necessitated the creation of a transmit-only birdcage coil. Coil performance of the phased array was evaluated electrically and on phantoms with clinical imaging protocols.

Ali Caglar Ozen^1,2, Michael Bock¹, and Ergin Atalar^2
1Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany, ²Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey

3D MRI with concurrent excitation and acquisition (CEA) is implemented with active decoupling of radio frequency coils. The transmit coil is geometrically decoupled from the receive coil, and the remaining B1-induced voltages in the receive coil during CEA are minimized by the second transmit coil using a careful adjustment of the phase and amplitude settings in this coil. CEA MR images could be reconstructed from an ex vivo animal.

Shajan G¹, David Zsolt Balla¹, Thomas Steudel¹, Philipp Ehses², Hellmut Merkle¹, Nikos Logothetis^1,3, Rolf Pohmann¹, and Klaus Scheffler^1,2
1Max Planck Institute for Biological Cybernetics, Tuebingen, Baden Wuerttemberg, Germany, ²Department of Biomedical Magnetic Resonance, University Hospital, Tuebingen, Baden Wuerttemberg, Germany, ³University of Manchester, Manchester, United Kingdom

Simultaneous investigation of electrophysiology and fMRI in non-human primates presents several challenges on RF coil design. Transmit coil structure should allow access for electrodes from different orientations to allow recordings from different brain regions. Receive arrays must be designed around head posts fixed on the animal head, leading to non-optimum coil orientations in the helmet. In cases with more than one head posts, the receive array must be on two separable halves of the helmet. We developed an RF coil arrangement that optimizes the SNR and provides access for recordings from different regions of the brain.

Andre Kuehne^1,2, Elmar Laistler^1,2, Anke Henning^3,4, Ewald Moser^1,2, and Nikolai I Avdievich^3
1Center for Medical Physica and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, ²MR Centre of Excellence, Medical University of Vienna, Vienna, Austria, ³Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, ⁴Institute for Biomedical Engineering, UZH and ETH Zurich, Zurich, Switzerland

We derive an analytical framework for analyzing the coil power efficiency impact of resonant inductive decoupling (RID) for arbitrary channel coils. It is applied to a two-channel array, and analytical expressions for load power deposition dependent on the resistive coupling factor, degree of coupling compensation and relative driving phase shift between elements are derived. The results show that coil performance can be enhanced or degraded by RID, depending on the exact coil application scenario, and great care needs to be taken in a practical setup.

Seunghoon Ha¹, Haoqin Zhu¹, and Labros Petropoulos^1
1R&D, IMRIS Inc., Minnetonka, MN, United States

A novel transceiver wireless array coil that can be utilized for robotic assisted MR guided interventions and radiosurgery procedures was presented. The coil assembly consists of a posterior unit comprising of eight channels transceiver array pattern and an anterior wireless transceiver loop array coil that is inductively coupled to the posterior part. The coil assembly generated a high uniform and sensitive B1+ profile over the entire hear without inhibiting valuable surgical space and compromising the sterile field. SAR calculations indicate that the presence of the anterior wireless transceiver loop array does not alter or enhance the SAR pattern behavior inside the human head.

Tao Zhang^1,2, Joseph Y Cheng^1,2, Paul D Calderon¹, Thomas Grafendorfer³, Greig Scott², Bob Rainey³, Mark Giancola³, Fraser Robb³, John M Pauly², Brian A Hargreaves¹, and Shreyas S Vasanawala^1
1Radiology, Stanford University, Stanford, CA, United States, ²Electrical Engineering, Stanford University, Stanford, CA, United States, ³GE Healthcare, WI, United States

Clinical pediatric MRI is often performed using receive coils designed for adult patients. The mismatch of the receive coils and the pediatric patients can cause degraded image quality. In this work, a 64-channel receive-only phased array dedicated for pediatric body MRI is designed and constructed. This coil array incorporates the quarter-wavelength-balun technique, achieves ideal coil decoupling, and is very flexible in one direction conforms to different pediatric patient sizes. Here, we validated the performance and flexibility of the coil array in phantom and in vivo studies.

Scott A. Blasczyk¹, John C. Bosshard¹, Neal A Hollingsworth¹, Brian J Bass¹, and Steven M Wright^1
1Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States

Imaging and spectroscopy of multiple nuclei with phased arrays has demonstrable utility in magnetic resonance. Our application involves imaging of deuterium and proton. Deuterium has been used for glucose monitoring, tracking bolus diffusion, and providing a signal lock. We have developed a dual-tuned, geometrically decoupled two-element receive array for sequential or interleaved imaging of proton (¹H) and deuterium (²H) at 1T. Array elements are detuned passively during transmit with crossed diodes, while transmit elements are detuned during receive using PIN diodes. ¹H and ²H Images of a deuterated water phantom taken at 1T are shown.

Zhang Qiong¹, Sun zhi guo¹, Liu Wei¹, and Wang jian min^1
1Siemens, ShenZhen, GuangDong, China