ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore Traditional Poster Session: Engineering
 2169 Edwin Eigenbrodt1 and Mary Preston McDougall2 1Texas A&M University, College Station, TX, United States, 2Biomedical Engineering, Texas A&M University, College Station, TX, United States Here we describe a six channel inexpensive FDM receiver, agnostic to the nuclei of interest or magnetic field strength, implemented straightforwardly using off-the-shelf products, portable, and easily used in conjunction with any system with a single trigger line. The architecture is straightforwardly scalable to 16 channels at a cost of approximately 1300 per channel. This work describes the receiver architecture and the capabilities are demonstrated by acquiring six channel images from a previously reported mouse array coil, two-channel 13C spectra, and comparing the SNR of the receiver to the Varian Inova system. 2174 Nicholas R. Payne1, Lionel M. Broche1, and David J. Lurie1 1Bio-Medical Physics, University of Aberdeen, Aberdeen, United Kingdom RF coil ringing following an excitation pulse is particularly problematic at low frequency and can prevent the measurement of signals from short-T2 samples or tissues; this issue can be addressed by Q-switching. A Q-switch circuit, designed to operate at 2.5 MHz and reduce the dead-time of an RF coil following an RF pulse, is described. The resulting reduction in coil dead-time allows signal to be detected earlier and RF pulses to be spaced closer together. MOSFETs are used in our design to isolate RF from the DC control system and the circuit can be inductively coupled to any RF coil. The device was found to reduce the duration of coil ringing by a factor of five. 2170 Jonas Reber1, Josip Marjanovic1, David Otto Brunner1, Andreas Port1, and Klaas Paul Pruessmann1 1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland With the number of RF receive channels cable routing and data handling becomes and increasing problem in particular for demanding applications requiring high acquisition duty cycles and bandwidths. To overcome this we present an MR acquisition platform that is capable of acquiring MR signal in-bore and scales its data handling ability with the number of channel. Furthermore the system provides ample, configurable real-time computational power for advanced in-line data processing and low-latency applications. 2184 Dhiraj Sinha1 and Shao Ying Huang1 1Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore An MRI system at small physical dimensions can be developed using a piezoelectric-microcantilever system with the capability of sensing magnetic fields in the range of microtesla to picotesla at room temperature conditions . The RF magnetic field induces voltage in the piezoelectric material which is amplified by the microcantilever which also filters out the signal around its resonant frequency. The cantilever vibration is measured using an optical detection system or by using capacitance to impedance converter. A thick block of piezoelectric material is used as a transmitter in order to replace the transmitting coil. 2179 Ali Caglar Özen1, Jan Korvink2, Ergin Atalar3, and Michael Bock1 1Dept. of Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany, 2Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany, 3Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey MRI with Concurrent Excitation and Acquisition (CEA) was shown to be feasible by achieving 80 dB analog isolation between transmit and receive coils using an active decoupling method. In this work, active decoupling system was upgraded using pick-up coils for simultaneous recording of the transmit signals. Preliminary results for MRI of a human wrist are represented and discussed. 2171 Stephen Ogier1, Mary McDougall1,2, and Steve Wright1,2 1Electrical and Computer Engineering, Texas A&M University, College Station, TX, United States, 2Biomedical Engineering, Texas A&M University, College Station, TX, United States Frequency translation is a technique that uses radiofrequency mixers to convert the received signal from one nucleus to another. This technique can be used to adapt 1H array receivers for use with other nuclei, such as 13C. This facilitates the use of arrays with less sensitive nuclei, which will benefit greatly from the SNR enhancement arrays provide.Frequency translation has been shown to provide a flexible means of adapting receivers for use with other nuclei without signal degradation or corruption. 2177 Zhoujian Li1, Sajad Hosseinnezadian1, Geneviève Guillot1, Georges Willoquet1, Laurène Jourdain1, Marie Poirier-Quinot1, Luc Darrasse1, and Jean-christophe Ginefri1 1Laboratoire d'Imagerie par Résonance Magnétique Médicale et Multi-Modalités, Université Paris-Sud, Orsay, France We have implemented a piezo-motor based automation system for contactless impedance matching of a monolithic Transmission Line Resonator (TLR) operating at 4.7 T. The automation system successfully achieved inductive matching to more than -30dB of the TLR inside the magnet and no artifacts was observed on the image of a rectangular box-shaped water phantom. A second image, acquired in the same condition but in the presence of another piezo-motor fixed on a side of the sample revealed that the close proximity of the piezo-motor to the sample brings B1-field inhomogeneity. 2176 Yu Li1, Fangfang Tang1, Bassem Henin1, Fabio Freschi1,2, Feng Liu1, and Stuart Crozier1 1School of ITEE, The University of Queensland, Brisbane, Australia, 2Department of Energy, Politecnico di Torino, Torino, Italy Eddy currents are inevitably induced in the electrically conductive surroundings including the magnet cryostat vessel, RF coil, RF shield and other peripheral metallic structures. This results in image distortion and artefacts. In order to control eddy currents, some studies have also discussed the issue of eddy currents on magnet cryostat vessel and RF shields. In this work, the eddy currents on a 12 channel micro-strip RF array head coil for 7T MRI were analysed and compared with that of a slotted, double-sided copper RF shield. A preliminary approach is proposed to reduce the eddy current effect, without compromising RF performance. 2180 Jonathan Y Lu1, Thomas Grafendorfer2, Fraser Robb3, John M Pauly1, and Greig C Scott1 1Dept of Electrical Engineering, Stanford University, Stanford, CA, United States, 2Advanced Coils, GEHC Coils, Stanford, CA, United States, 3GE Healthcare, Aurora, OH, United States We aim to demonstrate methods to wirelessly probe the MRI transmit state without access to the internal MRI hardware itself. We demonstrate two forms of RF pulse detection during a scan with simple magnetic field probes: 1) an electrical link undergoing peak detection and 2) an optical link. We process this signal as an external hardware interrupt into a microcontroller, which can be easily used to bias a coil between receive and transmit mode. Such a setup can be useful in future wireless receive coils. 2172 Sawson Taheri1, Pascal Stang2, John Pauly1, and Greig C. Scott1 1Stanford University, Stanford, CA, United States, 2Mountain View, CA, United States Broadcast amplifier pallets offer a low-cost solution in creating MR compatible non-magnetic transmit array systems capable of operating in both 1.5T and 3T B0 fields. We developed a locally deployable PTx array utilizing readily available broadcast amplifier pallets. The conversion of a conventional slow-gated, non-linear FM band (88-108MHz) 1kW pallet to a fast-gated, linear non-magnetic amplifier targeting transmit array deployment in both 1.5T and 3T B0 fields is demonstrated. 2178 Jennifer Nussbaum1, Simon Gross1, David O. Brunner1, Christoph Barmet1,2, Thomas Schmid1, Benjamin E. Dietrich1, Markus Weiger1, and Klaas P. Pruessmann1 1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Skope Magnetic Resonance Technologies, Zurich, Switzerland To measure the spatiotemporal magnetic field evolution during MR procedures for image reconstruction and real-time field control, best field probe performance is desired. We propose improved field probes with 19F spherical droplet samples formed and positioned with gelled deuterium oxide. It is shown that these spherical samples have an isotropic k-space range and thus de-phase less along the capillary than the common probes. Furthermore, with BIR-4 adiabatic plane rotation pulses the flip angle can be perfectly adjusted, opening a new realm of field monitoring methods. 2173 Oliver Heid1, Juergen Heller1, Xiaoyu Yang2, and Hiroyuki Fujita2 1Corporate Technology, Siemens AG, Erlangen, Germany, 2Quality Electrodynamics, Mayfield Village, OH, United States We propose direct digital RF switch mode current sources to eliminate image artifacts due to B1 field amplitude errors without time consuming transmitter calibration and adjustment. In difference to all known linear analog or switch mode RF amplfiers our proposal maintains high efficiency under modulation, and thus provides sufficent average RF power even at low flip angles, e.g. in FLASH sequences. We thus avoid significant, safety critical transmitter oversizing as in conventional MRI scanners. 2175 Jonathan Y Lu1, Thomas Grafendorfer2, Tao Zhang1, Kamal Aggarwal1, Fraser Robb3, John M Pauly1, and Greig C Scott1 1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Advanced Coils, GEHC Coils, Stanford, CA, United States, 3GE Healthcare, Aurora, OH, United States We examine different power depletion mode GaN HEMT devices for use in low power MRI Q-spoiling at 3T. These devices range in their on-resistance and off-capacitance, yielding different blocking impedances. We prototyped FET based Q-spoiling surface coils and compared SNR performances with conventional PIN diode Q-spoiling coils. Our coils enable Q-spoiling when unpowered providing a good safety feature. We tested the robustness of the FET devices in the coils by running fast spin echo sequences at 3T. The SNR performances of our FET based coils are comparable with conventional PIN diode coils without the high current draw. 2181 Natalia Gudino1, Jacco A de Zwart1, Qi Duan1, Peter van Gelderen1, and Duyn Jeff H1 1Advanced MRI section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States We demonstrate a new on-coil current-source switch-mode amplifier and communication setup for 7T imaging, which allows monitoring of the RF phase, frequency and amplitude at the amplifier output. This information is made available through a single optical signal per amplifier, making it a practical approach for safety monitoring and fast calibration of on-coil amplifier technology for parallel RF transmission. 2186 Hiroshi Kawaguchi1,2, Tkayuki Obata2,3, Hiromi Sano2, Eiji Yoshida2, Mikio Suga4, Yoko Ikoma2, Yukari Tanikawa1, and Taiga Yamaya2 1Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan, 2Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan,3Research Center for Charged Ion Therapy, National Institute of Radiological Sciences, Chiba, Japan, 4Center for Frontier Medical Engineering, Chiba University, Chiba, Japan The current attenuation correction method for human pelvic PET/MRI contains several problems such that the attenuation due to bone is not considered and a specific MR imaging, intended for attenuation correction only, is needed. In this study, we proposed a method to generate the distribution of attenuation correction factors with considering the bone attenuation using diagnostic T1-weighted MRI for pelvic PET/MRI scanning. The proposed method is the hybrid of the tissue segmentation based on Gaussian mixture model and the non-liner registration of tissue probability to a subject image. The simulation results showed that attenuation correction using the proposed hybrid method reduced the error on PET image than the conventional method. 2185 Aaron M. Coffey1, Panayiotis Nikolaou1, Kaili Ranta2, Iga Muradyan3, Matthew S. Rosen4, Samuel Patz3, Michael J. Barlow5, Boyd M. Goodson2, and Eduard Y. Chekmenev1 1Radiology, Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 2Southern Illinois University, Carbondale, IL, United States, 3Brigham & Women's Hospital, Boston, MA, United States,4Harvard University, Cambridge, MA, United States, 5University of Nottingham, Nottingham, United Kingdom We report on the development of a first and second generation 129Xe hyperpolarizers, capable of producing high (~25-90%) 129Xe hyperpolarization at high Xe densities (up to 2000 Torr partial pressure), suitable for clinical and materials MRS/MRI applications. 2183 Brian J Lee1,2, Ronald D Watkins1, Chen-Ming Chang1,3, and Craig S Levin1,4,5,6 1Radiology, Stanford University, Stanford, CA, United States, 2Mechanical Engineering, Stanford University, Stanford, CA, United States, 3Applied Physics, Stanford University, Stanford, CA, United States, 4Physics, Stanford University, Stanford, CA, United States, 5Electrical Engineering, Stanford University, Stanford, CA, United States, 6Bioengineering, Stanford University, Stanford, CA, United States We have developed a RF-penetrable PET insert for simultaneous PET/MRI and investigated the RF-penetrability with MR experiments and electromagnetic simulations. We have shown that the RF field from the MR body coil penetrates through the inter-module gaps and the ends of the PET insert. We found that ~60% of the RF field transmitted through the ends contributes to the B1 magnitude while the RF field entering through the gaps improves the uniformity provided the ends are also opened. The simulations also show that either shortening the length/height of the modules, or widening the gaps enhances the RF-penetrability by ~16%. 2187 Md Shahadat Hossain Akram1, Craig S. Levin2, Takayuki Obata1, Fumihiko Nishikido1, Eiji Yoshida1, and Taiga Yamaya1 1Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan, 2School of Medicine, Stanford University, Stanford, CA, United States A prototype of a novel oval shape PET insert for simultaneous body imaging with the MRI systems has been proposed in this study. The smaller prototype has the minor axis and major axis of 14 cm and 21 cm. 16 copper shielded boxes are positioned on the periphery of the oval frame. The shielding boxes were kept floating to let the RF field penetrate through the gaps in between the 16 modules. To get the required RF field distribution inside the oval PET, the gaps between the shielded modules were varied by doing assumptions following the conformal electric phase angle methods. B1 maps and GRE and SE images were taken and they have a good agreement with the results for without shielding materials. We have found a reduced RF field value with increased noise in the FOV which is mostly due to shielding materials. The images of GRE and SE have shape distortions due eddy currents. 2188 Maike E. Lindemann1, Jan Ole Blumhagen2, and Harald H. Quick1,3 1High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, 2Siemens Healthcare GmbH, Erlangen, Germany, 3Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany In quantitative PET-imaging, it is essential to correct the attenuation of photons in tissue. In combined PET/MR-imaging the attenuation correction (AC) is based on MR-data and subsequent tissue class segmentation. The MR-FOV is limited due to B0-inhomogeneities and gradient nonlinearities. Therefore, the AC-map is truncated and reconstructed PET-data are biased. HUGE (B0-Homogenization using gradient enhancement), which determines an optimal readout gradient to compensate gradient nonlinearities, is evaluated in phantom experiments and applied to MR-imaging of volunteers. The extension of the MR-FOV for MR-based AC showed an improvement of PET-quantification in integrated PET/MR-imaging by reducing the truncated areas of the AC-map. 2189 Meher Juttukonda1, Bryant Mersereau1, Yi Su2, Tammie Benzinger2, David Lalush1, and Hongyu An2 1Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, United States, 2Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, United States We propose a mapping-based, quantitative T1 method with patient-specific thresholding for tissue segmentation and assignment of continuous-valued LACs for soft tissues and bone. The proposed method utilizes images from a dual flip angle, dual echo UTE-MR acquisition to segment air, bone, GM, WM, CSF, fat and soft tissue. A conversion from MR relaxation rate R1 is then utilized to derive continuous-valued LACs to major tissues in the head/neck. The method has been validated in PET data from 23 subjects and has been shown to outperform the vendor UTE method in PET reconstruction accuracy. 2182 Spencer Baird Parent1, William Bradfield Handler 2, and Blaine A. Chronik2 1Medical Biophysics, Western University, London, ON, Canada, 2Physics and Astronomy, Western University, London, ON, Canada Using finite elements methods, an investigation of the systematic errors in magnetic field NMR probes is investigated. A NMR field probe is modeled and the field broadening and field offset is investigated as a function of the susceptibility of epoxy. It is shown that susceptibility matching the epoxy drastically reduces field broadening with a minimal effect on field offset. Additionally the effect of air bubbles present in cured epoxy is modeled and the results show that for certain critical regions of the probe the presence of an air bubble can be disadvantageous to the quality of the field probe. 2196 Mikayel Dabaghayan1, Shelley Hua Lei Zhang1, Zion Tsz Ho Tse2, Charles L Dumoulin3, Ronald Watkins4, Wei Wang1, Jay Ward5, and Ehud Jeruham Schmidt6 1Radiology, Brigham and Womens Hospital, Boston, MA, United States, 2Engineering, University of Georgia, Athens, GA, United States, 3Radiology, Cincinatti Childrens Hospital Medical Center, Cincinatti, OH, United States, 4Radiology, Stanford University, Stanford, CA, United States, 5E-Trolz Inc., North Andover, MA, United States, 6Radiology, Brigham and Womens Hospital, Newton, MA, United States We developed a technique to restore the ECG signals distorted by MRI gradient-induced voltages (GIV) acquired during fMRI and DW-EPI brain imaging sequences. Brain EPI sequences produce the largest ECG artifacts, presenting a large challenge to GIV removal. We used a theoretical equation with 19 parameters, which characterized the GIVs at each ECG electrode based on the simultaneously recorded gradient waveforms. A rapid training sequence permitted computing the equation coefficients, followed by real-time gradient-induced voltage removal during imaging. FIR notch filters were subsequently applied to remove some residual spikes. The method succeeded in removing most GIVs, excluding artifacts at the beginning and end of imaging periods, which resulted from amplifier non-linearity. 2198 Mohan Lal Jayatilake1, Christoph Juchem 2, Michael Mullen1, Gregor Adriany1, Robin de Graaf2, and Michael Garwood1 1Center for Magnetic Resonance Research, University of Minnesota, Minnesota, MN, United States, 2Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, United States A highly uniform magnetic field (B0) is typically required to generate MR images. In the original STEREO (for STEering REsonance over the Object) method, spatial variations in B0 are compensated by adjusting pulse amplitudes and frequencies in a temporal manner. Here we present a novel design of a limited set of well-defined multi-coil (MC) arrays that can optimize magnetic field distortions across the object of interest. 2199 Ryota Yamada1, Makoto Tsuda1, Katsumi Kose1, and Yasuhiko Terada1 1Institute of Applied Physics, University of Tsukuba, Tsukuba, Japan A multi-circular shim coil (MCSC), which consists of a set of localized circular current coils, provides the flexibility to design and produce linear and higher-order magnetic fields that compensate for a given B0imhomogeneity both statically and dynamically. However, the concept of the MCSC has currently been realized only for cylindrical base geometries. Here we translated the concept of the MCSC to a biplanar geometry, and a planar-type MCSC was designed and fabricated for an open, 1.0 T permanent magnet system. We concluded that the planar MCSC is a useful devise to achieve field homogeneity with reasonable accuracy. 2200 Lukas Winter1, Haopeng Han1, and Thoralf Niendorf1,2,3 1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine, Berlin, Germany, 2Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany, 3MRI.TOOLS GmbH, Berlin, Germany Cost effective open source imaging (COSI) is a collaborative initiative currently building an affordable low field open source MR scanner with the technical documentation available at www.opensourceimaging.org. As part of this initiative COSI Measure has been developed in order to automatically map the static magnetic field. COSI Measure is an open source multipurpose 3-axis system for ~3000€, which can be equipped with other field mapping probes like electromagnetic field sensors, used for 3D printing / CNC machinery application or other applications, that require programmable submillimeter movement and sensor readouts in space and time. 2190 Lindsey Alexandra Crowe1, Gibran Manasseh1, Aneta Chmielewski2, Thomas de Perrot1, Hajo Müller3, Rares Salomir1, and Jean-Paul Vallée1 1Division of Radiology, Faculty of Medicine, Geneva University Hospital, Geneva, Switzerland, 2University of Toronto, Hospital for Sick Children, Toronto, ON, Canada, 3Division of Cardiology, Geneva University Hospital, Geneva, Switzerland A new cardiac MRI triggering method is sought for cases of ECG signal complications due to pathology, or for fetal imaging. We propose feasibility of triggering to carotid ultrasound using an MRI compatible probe using spatially resolved Doppler compared to gold standard ECG. Retrospective processing using Metric Optimized Gating (MOG), is also included for comparison. Imaging modalities were compatible and the positioning of the US probe stable and patient friendly. Phase contrast flow and cine images were successfully obtained in healthy volunteers with ECG, Doppler triggering and MOG. Image quality is highly comparable and accurate functional parameters accessible. 2205 Hai Luo1, Bin Wang1, Gaojie Zhu1, Wenzhou Wang1, Xiang Zhou1, Ziyue Wu1, and Leping Zha1,2 1AllTech Medical Systems, Chengdu, China, People's Republic of, 2AllTech Medical Systems, Cleveland, OH, United States 3D dual echo gradient echo sequence is commonly used to obtain the field map for B0 shimming. The maps contain the true B0 fields mixed with eddy currents induced magnetic field changes averaged over the echo time difference, which compromise the shimming accuracy. A calibration sequence with alternating gradient polarities is proposed to measure the eddy currents term. Quadratic surface fitting is then applied to produce smooth eddy currents calibration maps over the full imaging volume containing only the first and second order components. The actual rapid in-vivo shimming sequence runs later, using the calibration maps to remove the eddy currents influences during the post-processing, with partial Fourier acquisition on phase encoding and slice encoding directions to reduce the scan time. The fast method provides means of eddy currents insensitive shimming, as well as reduced sensitivity to motion. 2206 Vanessa L. Landes1, Eamon K. Doyle1,2, Pablo J. Prado3, John C. Wood1,2, and Krishna S. Nayak4 1Biomedical Engineering, University of Southern California, Los Angeles, CA, United States, 2Cardiology, Children's Hospital Los Angeles, Los Angeles, CA, United States, 3One Resonance, LLC, San Diego, CA, United States, 4Electrical Engineering, University of Southern California, Los Angeles, CA, United States We investigate the use of a magnet with flat field isosurfaces over 4 cm for assessment of proton density fat fraction (PDFF). We experimentally demonstrate a correlation between PDFF and apparent T2 in phantoms. Apparent T2 measurement variability is low enough to produce invertible curves of T2 vs. PDFF in intervals of 2% PDFF for a 0 – 17% PDFF range at 0ºC and intervals of 4% PDFF for a 0 – 12% PDFF range at 23ºC in milk and cream mixtures. The long-term goal is to use this device for in-vivo clinical applications, such as measurement of intra-hepatic and intra-muscular fat. 2191 Mahdi Orooji1, Mehdi Alilou2, Rachel Sparks3, Mirabela Rusu4, Nicolas Bloch5, Ernest Feleppa6, Dean Barratt7, Lee Ponsky8, and Anant Madabhushi2 1Biomedical Engineering, CenteCase Western Reserve University, Cleveland, OH, United States, 2Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 3Centre for Medical Image Computing, University College of London, London, United Kingdom, 4Albany, NY, United States, 5Boston Medical Center, Boston, MA, United States, 6Lizzi Center for Biomedical Engineering, Riverside Research, New York, NY, United States, 7University College London, London, United Kingdom, 8University Hospital Case Medical Center, Cleveland, OH, United States To evaluate whether the combination of computer extracted or radiomic image parameters from two complementary modalities, MRI-TRUS can enable better prediction of presence of prostate cancer compared to either modality individually. We considered 12 slides who underwent MRI, TRUS prior to radical prostatectomy. Deformable co-registration methods were used for spatially aligning the pre-operative in vivo MRI and ultrasound with the ex vivo whole mount radical prostatectomy specimens to establish the ground truth for cancer extent on the imaging. It yielded the best separability between cancer and non-cancer regions with an Area under the operating characteristic curve of 0.88. 2192 Takuya Hinoda1, Yasutaka Fushimi1, Tomohisa Okada1,2, Ryusuke Nakamoto1, Yuji Nakamoto1, and Kaori Togashi1 1Radiology, Graduate school of Mediine, Kyoto University, Kyoto, Japan, 2Human Brain Research Center, Graduate school of Mediine, Kyoto University, Kyoto, Japan “Flexible PET (fxPET)”, a dual-head mobile DOI-TOF PET system with MR compatibility, is a newly developed device which enable us to examine the positron-emission tomography. In this first trial of the central nervous system (CNS), we tried to confirm the clinical feasibility of the fxPET with a 1.5T MRI scanner. The result of this study showed that fxPET have clinical feasibility in comparison with PET-CT. PET/MRI is an emerging modality. PET/MRI can provide us useful metabolic information to MRI images. 2208 Stefan Kroboth1, Kelvin J. Layton1, Feng Jia1, Sebastian Littin1, Huijun Yu1, Jürgen Hennig1, and Maxim Zaitsev1 1Medical Physics, University Medical Center Freiburg, Freiburg, Germany A matrix gradient coil consisting of 84 small coil elements was designed and constructed at our institution. Driving each coil element with an individual amplifier is impractical due to the high current requirements. To resolve this limitation, groups of coil elements can be connected in series and driven by a limited number of amplifiers. Such grouping configurations are obtained for one or several target fields. In the latter case, the configurations need to be switched with a switching circuit. We propose an algorithm to minimize the number of necessary switches to reduce the complexity and cost of this circuit. 2203 Yi Gao1,2,3 and Chuan Huang4,5 1Biomedical Informatics, Stony Brook Medicine, Stony Brook, NY, United States, 2Applied Mathematics and Statistics, Stony Brook Medicine, Stony Brook, NY, United States, 3Computer Sciences, Stony Brook Medicine, Stony Brook, NY, United States, 4Radiology, Stony Brook Medicine, Stony Brook, NY, United States, 5Psychiatry, Stony Brook Medicine, Stony Brook, NY, United States In simultaneous PET-MRI, attenuation correction is still a major hurdle due to the high attenuation of the bones and the lack of MR signal in conventional sequences. So far, several approaches have been proposed for bone attenuation correction, including bone segmentation and direct bone imaging. However, almost all available bone segmentation literatures focused on the head, which is arguably one of the easier regions because of its smaller field-of-view (FOV) requirement and the absence of major motion artifacts. Direct bone imaging is another promising approach which is accomplished by using zero-TE imaging, but its application in the body is challenging due to the larger FOV requirement and current instrumentation limitation such as peak B1. Recent research has demonstrated that PET quantitation can be largely improved even by assigning a fixed bone attenuation value (0.120 cm-1) to all bones. In light of this, we developed a technique that is able to produce good bone segmentation in the pelvic region using a 2-minute 6-echo DIXON MRI acquisition. 2194 Bryant G. Mersereau1, Meher R. Juttukonda1, Hongyu An2, and David S. Lalush1 1Joint Department of Bioengineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, United States, 2Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, United States Acquired PET-MR datasets can be problematic to build due to the high logistical and monetary cost associated with recruiting and scanning patients. We propose a new electronic PET phantom (E-phantom) platform to streamline the PET-MR research process. The proposed platform is shown to produce results consistent with acquired PET data reconstructed on manufacturer software and to provide high configurability and flexibility as a simulation tool. 2195 Camila Munoz1, Christoph Kolbitsch1,2, and Claudia Prieto1 1Department of Biomedical Engineering, King's College London, London, United Kingdom, 2Division of Medical Physics and Metrological Information Technologies, Physikalisch-Technische Bundesanstalt, Berlin, Germany MR-based PET motion correction has been shown to improve image quality in cardiac PET-MR imaging. Here we present a numerical simulation study analysing the impact of temporal and spatial resolution of motion fields on the final image quality of myocardial perfusion PET scans in order to find the most efficient parameters yielding accurate cardiac motion compensation in the shortest possible scan time. Results show that cardiac motion correction is important for accurate assessment of myocardial lesions and that temporal resolution of the motion fields can be strongly optimised without losing diagnostic accuracy, reducing the total exam time in PET-MR imaging. 2193 Md Shahadat Hossain Akram1, Takayuki Obata1, Mikio Suga2, Fumihiko Nishikido1, Eiji Yoshida1, and Taiga Yamaya1 1National Institute of Radiological Sciences, Chiba, Japan, 2Chiba University, Chiba, Japan Simultaneous PET/MRI system has attracted much because of its both functional and anatomic imaging capability. In our laboratory, we have developed a human head-size PET/RF-coil integrated modality to be used with existing clinical 3T MRI system (Siemens Magnetom Verio). Eight PET detector modules are integrated with a cylindrical 8-element Birdcage RF coil for simultaneous PET and MRI imaging. In the design each detector has been integrated in between two coil elements. RF interference to PET detector circuits affects PET performance. Also noise generated from PET circuits affects MR image quality. For proper simultaneous operation, PET circuits in each detector-module were installed inside a copper-shielded box. But shielding materials very close to RF coil elements and close to imaging region adversely affects MR imaging quality. In this study we performed Bo and SAR calculation of our hybrid system. Though there have noticeable changes in the Bo values, the SAR remains very low. 2204 Camila Munoz1, Radhouene Neji2, Peter Weale2, Rene Botnar1, and Claudia Prieto1 1Department of Biomedical Engineering, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare, Frimley, United Kingdom Respiratory motion remains a challenge for coronary MR angiography at 3T. Here we propose an inline 2D translational motion correction scheme using an image-based navigator. Low-resolution navigators are acquired at each heartbeat by spatially encoding the start-up echoes of an ECG-gated gradient echo sequence, allowing for 100% scan efficiency. Results from healthy volunteers show that motion correction improves visualization of the right and left anterior descending coronary arteries. The proposed scheme potentially allows for performing a comprehensive diagnosis of coronary artery disease by acquiring both diagnostic and motion information from MR, that can also be used to correct PET data. 2197 Ileana Hancu1, Robert Darrow1, Eric Fiveland1, Elizabeth Morris2, Dominic Graziani1, and Mauricio Castillo-Effen1 1GE Global Research Center, Niskayuna, NY, United States, 2Memorial Sloan Kettering Cancer Center, New York City, NY, United States Many factors contribute to the inaccuracy of MR-guided breast biopsies. Significantly, the lack of real-time visualization of tool advancement towards the biopsy site increases their duration and rate of false negatives. In this work, a novel approach for instrument tracking, relying on the spatial variation of the magnetic field, and using a set of 3 axis accelerometers/gyroscopes/magnetic field sensors, is presented. One dimensional tracking with 1.3mm rms error was demonstrated in the fringe field of a 3T magnet. 2201 Ferran Prados1,2, Manuel Jorge Cardoso1, Ninon Burgos1, Claudia Angela Michela Gandini Wheeler-Kingshott2,3, and Sebastien Ourselin1 1Translational Imaging Group, Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, 2NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, University College London, London, United Kingdom, 3Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy This work proposes a new way to publicly distribute image analysis methods and software. This approach is particularly useful when the software code and the datasets cannot be made open source. We leverage the use of Internet and emerging web technologies to develop a system where anyone can upload their image datasets and run any of the proposed algorithms without the need of any specific installation or configuration. This service has been named NiftyWeb (http://cmictig.cs.ucl.ac.uk/niftyweb). 2202 Luca Zilberti1, Oriano Bottauscio1, and Mario Chiampi2 1Istituto Nazionale di Ricerca Metrologica, Torino, Italy, 2Dipartimento Energia, Politecnico di Torino, Torino, Italy This contribution reports the results of an extended survey, in which the exposure indexes provided by the current Guidelines dealing with motion-induced fields in MRI environments have been computed. The analysis is carried out through numerical simulations, using detailed human models that experience realistic exposure conditions (motion trajectories and MRI scanners). Besides identifying some critical situations (where the exposure indexes may be exceeded), the research puts in evidence some degree of freedom in the evaluation procedure, which might lead to inconsistences between different assessment approaches. 2207 Kilian Wolfgang1, Frank Seifert1, Silvia Knappe-Grüneberg1, Jens Voigt1, Eva Al-Dabbagh1, and Isaac Fan1 1Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany Two distinct methods for precise flip angle determination for hyperpolarized rare gas samples are presented and were performed in ultra low magnetic field environment ($$\approx\,\mu$$T). The repetitive coherent excitation method is rather fast and allows for preserving most of the initial polarization whereas the incoherent excitation method is time consuming but determines the relaxation parameters $$T_1$$$and $$T_2^\star$$$ inherently.