Electronic Posters : Other
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Spectroscopy - Other

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 46

14:00 3472.   Gender differences in GABA and glutamate concentrations measured with MEGA-PRESS 
Ruth L O'Gorman1, Lars Michels1, Richard Edden2, and Ernst Martin1
1University Children's Hospital, Zürich, Switzerland, 2Russell H Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD, United States

Few studies have examined the normal inter-subject variability in MRS GABA and glutamate (Glu) concentrations with factors like age and gender. This study investigates age- and gender-related differences in GABA and Glu in a group of healthy adults. No significant age effects were seen, but GABA, Glu, and Glx (glutamate+glutamine) levels were significantly higher in the male participants. These significant differences are independent of the grey and white matter fraction in the MRS voxel and emphasize the importance of gender-matching for GABA and Glu MRS studies with mixed-cohort subject groups.

14:30 3473.   Regional Variations in GABA Measured with MEGA-PRESS 
Christopher John Evans1, Frederic Boy1, Richard A E Edden2, Krish D Singh1, and Petroc Sumner1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, Wales, United Kingdom, 2Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, United States

In this work, we report on the regional differences in human GABA levels, measured with MEGA-PRESS. Six regions were studied - anterior cingulate, dorsolateral pre-frontal cortex, inferior frontal gyrus, supplementary motor area, parietal lobe and occipital lobe. There was a significant effect of region and of voxel grey matter fraction on GABA. The measured differences in GABA not attributable solely to differences in the tissue composition across regions.

15:00 3474.   Motor Control Predicted by GABA Concentration in the Supplimentary Motor Area 
Christopher John Evans1, Frederic Boy1, Richard A E Edden2,3, Krish D Singh1, Masud Husain4, and Petroc Sumner1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, Wales, United Kingdom, 2Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, United States, 3F.M. Kirby Research Center for Functional MRI, Kennedy Krieger Institute, Baltimore, United States, 4UCL Institute of Cognitive Neuroscience & UCL Institute of Neurology, UCL, London, England, United Kingdom

The concentration of inhibitory neurotransmitter GABA has previously been demonstrated to predict participants’ performance in visual behavioural tasks. Here, we demonstrate that GABA concentration correlates with the performance of participants in a motor task closely associated with behavioural inhibition (the Negative Compatibility Effect, NCE). Individual differences in participants' NCE is explained by differences in participants GABA levels in the supplementary motor area, but not correlated with other brain regions.

15:30 3475.   1H MRS at 7T demonstrates a strong correlation between stimulus-induced lower case Greek gamma-frequency in the visual cortex and the glutamine/GABA ratio. 
Mary Charlotte Stephenson1, Matthew J Brookes1, Darren Price1, Antonio Napolitano2, Susan T Francis1, and Peter G Morris1
1School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, 2Academic Radiology, University of Nottingham, United Kingdom

The peak frequency of stimulus-induced visual lower case Greek gamma-oscillations, measured using magnetoencephalograpy, has been shown to be predicted by the resting concentration of lower case Greek gamma-amino butyric acid (GABA). However, cortical network models show that the oscillatory frequency depends on the balance between excitatory and inhibitory neurotransmitters. In this study we utilize the increased spectral resolution and signal available at 7T to quantify glutamate, glutamine and GABA. Our results indicate a stronger correlation between lower case Greek gamma-frequency and glutamate/GABA than for GABA alone. The strongest correlation was found for glutamine/GABA where the glutamine concentration is thought to be closely related to the glutamate neurotransmitter pool size

Tuesday May 10th
  13:30 - 15:30 Computer 46

13:30 3476.   Feasibility of Quantitative Proton MR Spectroscopy Without Water Suppression in In Vivo Malignant Breast Lesions at 1.5T 
Hyeon-Man Baek1
1Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, United States

Recently, in vivo 1H-MRS acquired with water suppression has been proven helpful for the detection and therapy response monitoring of breast cancer based on total choline-containing compounds (tCho). However, the role of 1H-MRS acquired without water suppression is less established. The aim of our study was to determine whether quantitative results from the breast cancer can show good agreement between the estimated tCho levels in water-suppressed and unsuppressed spectra. There was a statistically significant correlation between the estimated tCho concentration levels by 1H-MRS with and without water suppression (r2 = 0.462, p =0.001). This result demonstrates the feasibility of in vivo quantitative 1H-MRS without water suppression for the measurement of tCho concentrations from in vivo malignant breast lesions.

14:00 3477.   Increase in SNR for 31P MR spectroscopy by integrating polarization transfer and direct detection in one repetition time. 
Wybe van der Kemp1, Vincent Boer1, Peter Luijten1, Jannie Wijnen1, and Dennis Klomp1
1Department of Radiology, University Medical Centre, Utrecht, Netherlands

Here we show for 31P MR spectroscopy that by integrating polarization transfer (BINEPT) and a spin echo (SE) in one repetition time, one can gain extra signal to noise for the BINEPT as compared to spectra from separate BINEPT and SE sequences. The BINEPT signal is hardly affected by the subsequent SE. However, the BINEPT signal has some saturating effect on the SE signal. Alternatively, the integrated sequence can be used to obtain an BINEPT at the same SNR, but with the additional information on metabolite content that direct detection offers.

14:30 3478.   Optimal recombination of multi-coils CSI data using image based sensitivity map 
Michaël Sdika1, Yann Le Fur1, and Patrick J Cozzone1
1CRMBM, CNRS, UMR 6612, Faculté de Médecine de Marseille, Université de la Méditerranée, Marseille, France

This work addresses the problem of the optimal recombination of multi-coil chemical shift imaging (CSI) data. Eddy current correction is performed using the unsuppressed water signal. Coil sensitivity maps are computed using low resultion images and optimal recombination formula are derived.

15:00 3479.   MISSA - A highly-developed clinical tool for MR Spectroscopy 
Bernd Merkel1, Markus T. Harz1, and Horst K. Hahn1
1Fraunhofer MEVIS, Bremen, Germany

MR Spectroscopy hasn't found the way into clinical routine yet. For one reason, most of the existing devices and software assistants lack of performance or difficult handling. We present the novel research prototype MISSA (MEVIS Imaging and Spectroscopy Software Assistant) for the analysis of single- (in vivo, ex vivo) and multi-voxel (2D, 3D) spectroscopy. All standard processing steps are included, together with different quantification methods, which can be easily extended. Furthermore, 3D-visualization, PACS connection and the possibility of voxel-labeling with export to machine learning algorithms are integrated. Therefore, it is our goal to improve and simplify MRS data analysis.

Electronic Posters : Other
Click on to view the abstract pdf and click on to view the video presentation.

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 47

14:00 3480.   Calculation of Shear Stiffness in Noise Dominated Magnetic Resonance Elastography (MRE) Data Based on Principal Frequency Estimation. 
Kiaran Patrick McGee1, David Lake1, Yogesh Mariappan1, Armando Manduca1, Rolf Hubmayr2, and Richard Ehman1
1Department of Radiology, Mayo Clinic, Rochester, MN, United States, 2Pulmonology and Critical Care Medicine, Mayo Clinic, Rochester, MN, United States

A method for calculating the shear stiffness from magnetic resonance elastography data under conditions of low signal-to-noise ratio (SNR) is described. It is based on the analysis of the spectral content of the propagating shear wave field from which the principal spatial frequency is identified and ultimately shear stiffness calculated. Finite element simulations and ex vivo lung experiments were performed to evaluate the sensitivity of this approach in comparison to the local frequency estimation (LFE) method. Results indicate that principal frequency analysis accurately estimates shear stiffness in comparison to commonly applied LFE-based estimates under low SNR conditions.

14:30 3481.   Geometric Focusing of High Frequency Shear Waves for Noninvasive High Resolution MR Elastography 
Thomas J Royston1, Temel Kaya Yasar1, and Richard L Magin1
1University of Illinois at Chicago, Chicago, IL, United States

We combine the benefits of noninvasiveness and geometric focusing of the rapidly attenuating shear waves to extend the useful shear wave frequency range, and thus achieve very short shear wavelengths that will help in providing more localized estimates of material properties using MR elastography on in vitro tissue specimens or materials. This is accomplished by vibrating the entire sealed test tube axially, effectively using the entire inner test tube wall as an axisymmetric shear wave source that creates waves travelling radially inward. The basic theory supporting this approach is followed by a description of our experimental setup and pilot results.

15:00 3482.   Physical Boundary Conditions Reconstruction: a Novel Method to Determine Viscoelastic Parameters from Magnetic Resonance Elastography Data 
Philippe Garteiser1, Sabrina Doblas1, Bernard E. VanBeers1,2, Valérie Vilgrain2, and Ralph Sinkus1
1INSERM UMR 773, Centre de Recherche Biomédicale Bichat-Beaujon, Clichy, France, 2Department of Radiology, Beaujon University Hospital, Paris Diderot University, Clichy, France

The conventional reconstruction of viscoelastic parameters in MR-Elastography (MRE) is challenging in the presence of the signal noise levels typically encountered in clinical datasets. A novel algorithm is proposed, which stabilizes the noisy wave equation inversion problem by injecting constraints arising from the underlying physics into the system. As a result, the viscoelastic parameters accurately reflect the input data while also obeying necessary basic physical constraints, gaining stability in the process. Proof of concept is provided on simulated noisy waves and on clinically relevant experimental data from a cohort of patients with diffuse liver disease.

15:30 3483.   Hardware and Software Design for Serial and Longitudinal Rat MR Elastography Studies 
Kevin John Glaser1, Jun Chen1, Meng Yin1, Thomas Hulshizer1, Phillip Rossman1, and Richard Ehman1
1Radiology, Mayo Clinic, Rochester, MN, United States

This work demonstrates an approach to rat liver MR elastography (MRE) designed to facilitate serial and longitudinal studies of hepatic stiffness for applications such as monitoring disease progression and treatment efficacy. A large, thin driver was constructed that allowed for rapid positioning of each animal, and a rapid EPI MRE acquisition was used to measure liver stiffness. Results are shown demonstrating hepatic changes in rats due to a bile duct ligation (BDL) surgery over 4 weeks compared to rats given a sham surgery.

Tuesday May 10th
  13:30 - 15:30 Computer 47

13:30 3484.   Evaluating the Feasibility of Multi-Slice Endorectal Magnetic Resonance Elastography for Prostate Cancer Localization 
Arvin Arani1,2, Donald Plewes1,2, and Rajiv Chopra1,2
1Imaging Research, Sunnybrook Research Institute, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada

Purpose: To evaluate the feasibility of multi-slice endorectal MR elastography (MRE) over a volume equivalent to the prostate, for the application of identifying localized prostate cancer. Methods: Experiments were conducted in a prostate mimicking phantom embedded with tumour mimicking inclusions. MRE was performed by mechanically coupling an endorectal coil to a custom made piezoceramic actuator. Results: Multi-slice endorectal MRE was feasible over the entire 60cc prostate volume (27 slices, 2mm slice thickness). Conclusions: The results of this study, in combination with the clinical availability of an endorectal coil, motivate further investigation of endorectal MRE in patients.

14:00 3485.   MR-Elastography, a new biomarker of the tumor vascularization in a colon cancer mice model 
Lauriane Jugé1, Bich-Thuy Doan2, Johanne Seguin2, Miguel Albuquerque1, Benoit Larrat3, Daniel Scherman2, Valerie Vilgrain1, Valérie Paradis1, Bernard E. Van-Beers1, and Ralph Sinkus1
1CRB3 / UMR 773, CLICHY, Ile de France, France, Metropolitan, 2UMR 8151, Unité de pharmacologie chimique et génétique et d’Imagerie, -UPCGI/Chimie-Paristech, Paris, France, Metropolitan, 3Institut Langevin, ESPCI, Paris, France, Metropolitan

Assessment and follow-up of angiogenesis are major challenges in cancer. We studied the alterations of the vascularization during the spontaneous growth of a murine colon tumor and after a treatment with an antivascular agent. We obtained T2-weighted, 3D steady-state MR-Elastography and Diffusion MR images. After the MR examinations, the tumors were excised for histological analysis (CD31 and KI67 immunohistology). Our results show that it was possible to follow the evolution of a tumor and the efficacy of an antivascular agent using MRE. It was also shown that the viscosity and the elasticity are potentially new biomarkers to trace alterations of the vascularization.

14:30 3486.   Measuring the Transient before Steady-State in Brain MR Elastography 
Curtis L Johnson1, Bradley P Sutton2,3, and John G Georgiadis1,3
1Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 3Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States

The time required for shear waves to reach steady state in Magnetic Resonance Elastography (MRE) of the brain is investigated. The temporal evolution of the in-plane displacement field of the brain was determined by employing SPAMM tagging with HARP processing during the typical head vibration used in MRE. Proper orthogonal decomposition of this field is then used to determine the time required for the brain to reach steady state. This information is of use to brain MRE practitioners for optimizing the actuation and acquisition method.

15:00 3487.   Hydraulic conductivity estimation using magnetic resonance elastography 
Adam J Pattison1, Phillip R Perrinez1, Matthew D.J. McGarry1, John B Weaver1,2, and Keith D Paulsen1,3
1Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, United States, 2Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States, 3Norris Cotton Cancer Center, Lebanon, New Hampshire, United States

While linear elastic and viscoelastic material models are the norm for magnetic resonance elastography (MRE), poroelasticity may better estimate properties of biphasic material like brain tissue. Further, this algorithm allows for estimation of hydrodynamic material parameters such as pore pressure, porosity, and hydraulic conductivity. Defined as the rate at which fluid penetrates through pores, hydraulic conductivity may provide new clinical information like differentiation between normal and tumorous tissues and detection of increased intracranial pressure. In a recently developed poroelastic algorithm, this parameter can be estimated with high accuracy and resolution in simulated phantoms and may become an important biomarker in disease processes.

Wednesday May 11th
  13:30 - 15:30 Computer 47

13:30 3488.   Quantitative Measurement of Brain Deformation Caused by Pressure Loading of the Skull 
Erik H. Clayton1, Agus Priatna2, Bradley D Bolster, Jr.3, and Philip V Bayly1,4
1Mechanical Engineering & Material Science, Washington University in St. Louis, St. Louis, MO, United States, 2MR R&D Collaborations, Siemens Healthcare, St. Louis, MO, United States, 3MR R&D Collaborations, Siemens Healthcare, Rochester, MN, United States, 4Biomedical Engineering, Washington University, St. Louis, MO, United States

Traumatic brain injuries (TBI) are common and often lead to permanent cognitive impairment, yet the condition remains poorly understood. Computer simulations of injury mechanics offer enormous potential for the study of TBI; however, they require accurate experimental data for validation. In this study, Magnetic Resonance Elastography (MRE) imaging is used to measure brain tissue motion for the purposes of calculating strains imposed by acoustic extra-cranial pressure loading at 45 60, & 80 Hz. The unique features of this study are knowledge of the external loading (pressure amplitude) and the quantification of the brain’s response in terms of mechanical strain.

14:00 3489.   Whole brain MRE with guided pressure waves 
Xavier Maitre1, Emeline Lamain1, Ralph Sinkus2, Bruno Louis3, and Luc Darrasse1
1IR4M (UMR8081), Univ Paris-Sud, CNRS, Orsay, France, 2Centre de Recherches Biomedicales Bichat-Beaujon (UMR773), CRB3, Inserm, Paris, France, 3Biomecanique Cellulaire et Respiratoire (U841), IMRB, Inserm, Creteil, France
For a given acquisition sequence, the sensitivity of MR-elastography relies on the strength of the shear waves which may be induced in the targeted organ. For the last ten years, the brain has proven to be rather well decoupled from any mechanical excitations by the natural shielding layers. A very different approach from current devices was taken here. By guiding pressure waves into the buccal cavity, it was possible to generate, throughout the brain, shear waves in the three directions such that whole brain MRE could be performed and 3D maps of dynamic and loss shear moduli could be reconstructed.

14:30 3490.   Non-Contact Driver System for MR Elastography of the Breast 
Jun Chen1, Kevin J Glaser1, Eric G Stinson1, Jennifer L Kugel1, and Richard L Ehman1
1Mayo Clinic, Rochester, MN, United States

Used in combination with dynamic CE-MRI, MRE has shown promising results for characterizing breast disease. Previously described MRE drivers contact the breasts directly for wave transmission into the breasts, with several disadvantages: (1) deforming the breasts; (2) the variability in mechanical coupling, depending on breast size; (3) requiring modification of the breast RF coil; (4) interfering with MRI-guided breast biopsy. This study evaluated an indirect-contact breast driver that does not require direct breast contact and can be used with any breast coil. The results demonstrated shear wave illumination of breast tissue equivalent to or better than existing drivers.

15:00 3491.   Modeling Strain-Encoded (SENC) MRI for Use in Clinical Breast Imaging 
Ahmed Amr Harouni1, Nael F Osman2, and Michael A Jacobs3
1Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, United States, 2Department of Radiology, Johns Hopkins University, Baltimore, Maryland, United States, 3Department of Radiology and Oncology, Johns Hopkins University school of medicine, Baltimore, Maryland, United States

Previously, we proposed using mass stiffness to increase specificity of breast cancer detection using MRI. We used strain-Encoded (SENC) MRI to measure strain, which is inversely proportional to stiffness. However, since SENC was originally developed for cardiac applications, 30% compression was used. In this work, we investigate the minimum compression required to apply in order to detect and classify breast masses through finite element method simulations and phantom experiments. Our results, shows that we can detect masses with low compressions (5-10%), but in order to classify benign from malignant masses we need to use higher compression (10-15%).

Thursday May 12th
  13:30 - 15:30 Computer 47

13:30 3492.   Feasibility of brain MR-Elastography at 1.5 T with a novel wave generator: An animal study 
Najat Salameh1, Line Souris1, Mathieu Sarracanie1, Ludovic de Rochefort1, Ralph Sinkus2, Luc Darrasse1, and Xavier Maître1
1IR4M (UMR 8081), Université Paris-Sud 11, Orsay, France, 2Inserm U979 - CNRS (UMR 7587), Institut Langevin, Paris, France
Protected by the meninges and the skull, the brain is a challenging organ for Magnetic Resonance Elastography. The challenge persists in rodents despite the smaller dimensions since waves with higher frequencies and lower penetration depth must be accordingly applied to resolve the animal brain structures. In the present study, a new excitation mode, where pressure waves are directly guided into the animal mouth, is proposed. Proof of concept and optimization of the technique were carried out onto gel phantoms at 1.5 T. In vivo rat brain MRE was then performed.

14:00 3493.   A Novel Cardiac Phantom to Study Murine and Human Cardiac Motion and Function using MRI 
Christakis Constantinides1, Dimitris Nearchou1, Christoforos Constantinou1, Panayiotis Ktorides1, Robert Gravett2, and Vasilios Tzagarakis3
1Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus, 2Shelley Medical Imaging Technologies, London, Ontario, Canada, 3Alpha Evresis Diagnostic Center, Nicosia, Cyprus

A novel cardiac MRI phantom is presented. Such phantom is scalable to both the human and mouse hearts and can be used in low and high field MRI systems. It constitutes the technological platform for detailed ex-vivo electro-mechanical studies of the cardiovascular system at the tissue and organ levels in mice and humans.

14:30 3494.   Measurement of Ferret Brain Tissue Stiffness in vivo Using MR Elastography 
Yulin V Chang1, Yuan Aaron Feng1, Erik H Clayton1, and Philip V Bayly1
1Mechanical Engineering, Washington University, St. Louis, MO, United States

We present our initial experience of measuring brain tissue stiffness in adult ferrets at several frequencies using MR elastography. The average dynamics storage modulus of the ferret brain is measured to be 3.6 ± 1.3 kPa at 400 Hz. Our results suggest that the ferret brain appears to be slightly stiffer than the mouse brain and softer than brain measured at similar frequencies. We also observed frequency dependence of the brain tissue stiffness in the ferret.

15:00 3495.   Single-shot cardiac MR Elastography 
Sebastian Hirsch1, Thomas Elgeti1, Dieter Klatt1, Juergen Braun2, and Ingolf Sack1
1Department of Radiology, Charité - University Medicine Berlin, Berlin, Germany, 2Institute of Medical Informatics, Charité - University Medicine Berlin, Berlin, Germany

A single-shot echo-planar imaging (EPI) cardiac MRE technique is introduced which provides harmonic displacement images of the heart within 20 to 70 ms acquisition time depending on the desired motion sensitivity and image resolution. This method allows one to study multiple effects of wave dynamics in confined media with time-varying elastic and geometrical properties. Single-shot EPI-MRE facilitates time-resolved evaluation of wave amplitudes as a possible marker for myocardial dysfunction.

Electronic Posters : Other
Click on to view the abstract pdf and click on to view the video presentation.
Non-Proton MRI

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 48

14:00 3496.   Visualization and quantification of intestinal transit and motor function by real-time tracking of 19F labeled capsules in humans 
Tobias Hahn1, Sebastian Kozerke1, Werner Schwizer2, Michael Fried2, Peter Boesiger1, and Andreas Steingoetter1,2
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland

A combined 19F and 1H MRI framework enabling the co-registration of local intestinal motor function and transit assessed by 19F MRI with anatomical 1H MRI data was implemented and its potential for physiological GI MRI demonstrated. Biologically inert and impermeable 15C5 labeled capsules were developed. Capsule movement and gastric transit upon oral administration of one and two capsules were monitored in real time by a 19F projection imaging sequence using a 3T whole-body system equipped with a dual-channel 19F transmit-receive surface coil. The developed framework was found to be feasible for the non-invasive visualization and quantification of gastrointestinal motor activity.

14:30 3497.   In vivo gastrointestinal transit study using double-labelled markers 
Elisa Placidi1, Caroline L Hoad1, Luca Marciani2, Alan C Perkins3, P E Blackshaw3, Robin C Spiller2, and Penny A Gowland1
1SPMMRC, Nottingham, Nottinghamshire, United Kingdom, 2Nottingham Digestive Diseases Centre Biomedical Research Unit, Nottingham, United Kingdom, 3Academic Medical Physics, Nottingham, United Kingdom

A pilot in vivo study measuring gastrointestinal transit with MRI is presented. Purpose built plastic capsules, double labelled with a fluorine agent and a gadolinium solution were given to two volunteers scanned up to 48 hours. The Gadolinium solution gave a very bright signal which could be identified at all time points in the entire GI tract. The fluorine image gave confirmation of their position but the fluorine coil often had to be repositioned after the exact location of the capsules was established. In future it will be possible to perform studies of GI transit using just 1H labelled capsules.

15:00 3498.   19F-MRI: Flow Measurement of Fluorinated Gases During High Frequency Oscillatory Ventilation 
Janet Friedrich1, Julien Rivoire1, Maxim Terekhov1, and Laura Maria Schreiber1
1Section of Medical Physics, Johannes Gutenberg University Medical Center, Mainz, Germany

High frequency oscillatory ventilation (HFOV) is a protective ventilation method mainly used for patients with acute respiratory distress syndrome (ARDS). To explore gas flow mechanisms during HFOV 19F-MRI of fluorinated gases was performed at 1.5T. With a flow sensitive gradient-echo-sequence velocity profiles during HFOV could be determined and tracked over time with a temporal resolution of 10ms. The signal-to-noise ratio and hence the reliability of velocity information could be improved by skipping the phase encoding gradient. In summary, the present work demonstrates that flow measurement of fluorinated gases is feasible and can also be applied under HFOV.

15:30 3499.   Feasibility of in vivo phosphorus imaging of cortical bone at 7T in humans 
Ping-Huei Tsai1, Alan C Seifert1, Alexander C Wright1, Hamidreza S Rad1, Jeremy F Magland1, Hee Kwon Song1, Mary B Leonard2, and Felix W Wehrli1
1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Center for Clinical Epidemiology and Biostatistics, Children¡¦s Hospital of Philadelphia, Philadelphia, PA, United States

Osteomalacia is characterized by hypomineralization of bone, i.e., low phosphorus concentration, and a noninvasive means to assess bone phosphorus would be desirable. However, 31P MR signals from bone have low SNR due to extremely short T2* and long T1, as well as small gyromagnetic ratio. High-field scanners and 3D radial imaging sequences can mitigate these limitations. The purpose of this study was to design and evaluate the peformance a 3D radial imaging technique and customized RF coils to obtain in-vivo phosphorus images of human cortical bone at the mid-shaft tibia at 7T. Preliminary results demonstrate the method¡¦s feasibility and suggest the potential for quantitative measurements.

Tuesday May 10th
  13:30 - 15:30 Computer 48

13:30 3500.   Development of dual-tuned knee coil at 7T: a feasibility study of high-resolution sodium MR imaging and T2 mapping in knee cartilage in vivo 
Junghwan Kim1, Bumwoo Park1, Alessandro Furlan1, Chanhong Moon1, Sung-hong Park1, Tiejun Zhao2, and Kyongtae Ty Bae1
1Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States, 2MR Research Support, Siemens Healthcare, Pittsburgh, PA, United States

We have developed a dual-tuned proton/sodium knee RF coil at 7T and obtained high-resolution sodium MR imaging and T2 mapping of human knee cartilages within clinically acceptable time. Further studies on coil optimization and reproducibility of sodium concentration measurement should be followed for the clinic application.

14:00 3501.   A triple-resonant coil system for inherently co-registered proton-, sodium- and chloride-MRI at 9.4T 
Friedrich Wetterling1, Saema Ansar2, Laurant Tritschler2, Raffi Kalayciyan1, Stefan Kirsch1, Marc Fatar2, Stephen Meairs2, and Lothar R. Schad1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, 2Departmenet of Neuroloy, Heidelberg University, Mannheim, Germany

The aim of this project was to develop a triple resonant 1H/23Na/35Cl coil system for investigations on a rat stroke model without the need to exchange resonators during the measurements. The newly-developed coil system was composed of a linear 1H birdcage resonator and a double-tuned 35Cl/23Na surface coil. 1H imaging capability enabled the use of standard stroke sequences such as diffusion- and T2 weighted MRI. The coil performance was successfully tested on a 1H/35Cl/23Na-phantom. First brain images at 5 days after stroke confirmed the excellent coil performance for in vivo imaging.

14:30 3502.   Evaluation of B0-Inhomogeneity Correction for Triple-Quantum-Filtered Sodium MRI of the Human Brain at 4.7T 
Adrian Tsang1, Rob Stobbe1, and Christian Beaulieu1
1Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada

B0-inhomogeneities may cause regional signal loss on triple-quantum-filtered (TQF) sodium images. Three phase cycling algorithms were proposed recently to rectify this adverse effect with the cost of extensively increasing scan time; however, these were all only verified on small agarose phantoms. The goal of our study is to evaluate the extent of off resonance signal loss and their correction on human brain sodium TQF images and to determine whether the considerable two fold increase in scan time is warranted for in vivo studies.

15:00 3503.   Rodent Glioma Chemotherapy and Sodium MRI at 21.1T 
Victor D. Schepkin1, Fabian Calixto Bejarano1, Thomas Morgan2, Shannon Gower-Winter2, and Cathy W. Levenson2
1CIMAR/MRI, NHMFL/FSU, Tallahassee, Florida, United States, 2Biomedical Sciences, FSU, Tallahassee, Florida, United States

The diagnostic value of sodium MRI has not been established; however, the evidence of its potential is growing with the availability of high magnetic fields. Rodent glioma therapy by BCNU was thoroughly evaluated by sodium and diffusion MRI. The time courses of tumor responses reveal loss of the tumors’ intracellular sodium gradients early on during therapy, demonstrating it can be part of the in vivo apoptotic process. This finding correlates with multiple evidences already found in vitro. The effect of positive therapy can be detected for each animal individually in a day after initiation of treatment.

Wednesday May 11th
  13:30 - 15:30 Computer 48

13:30 3504.   In Vivo Brain Sodium T2* Mapping with a Multiple-echo Flexible TPI Sequence 
Aiming Lu1, Ian C Atkinson1, and Keith R Thulborn1
1Center for MR Research, University of Illinois, Chicago, IL, United States

The sodium MR signal is affected by the local electrical field gradient and exhibits bi-exponential relaxation behavior in brain. The relaxation times not only are critical parameters for optimizing the sequences for quantifying tissue sodium concentration, but also convey information on the local sodium ion environment. However mapping the relaxation times of sodium in biological tissues in vivo is challenging. We demonstrate here with an efficient multiple-echo flexible twisted projection imaging sequence that high quality T2* maps of the sodium MR signal in the entire human brain can be achieved within a reasonable scan time at 3T.

14:00 3505.   Sodium Relaxation Times in the Knee Joint In Vivo at 7T 
Guillaume Madelin1, Alexej Jerschow2, and Ravinder R Regatte1
1Radiology Department, New York University Medical Center, New York, NY, United States, 2Chemistry Department, New York University, New York, NY, United States

This preliminary work shows the feasibility of sodium T1 and T2* measurements in vivo on 8 healthy volunteers in 4 different regions (patellar, medial, lateral and condyle) of the articular cartilage at 7T and in a reasonable time for the patient (~35 min for each relaxation time). Sodium relaxation maps are calculated and could be useful as information complementary to the sodium concentration maps for assessing early osteoarthritis (OA) in patients, as T2* and T1 are expected to change with cartilage degeneration. Future improvements may include fluid suppression for reducing partial volume effects and a systematic study of OA patients.

14:30 3506.   In Vivo Breast Sodium T1 Measurements Using Inversion Recovery 3D Cones 
Joshua Kaggie1, Danny Park2, Rexford D Newbould3, Glen R Morrell4, Brian Hargreaves5, Ernesto Staroswiecki5,6, Gary E Gold5, and Neal K Bangerter2
1Physics, University of Utah, Salt Lake City, UT, United States, 2Electrical & Computer Engineering, Brigham Young University, Provo, UT, United States, 3GSK Clinical Imaging Centre, London, United Kingdom, 4Radiology, University of Utah, Salt Lake City, UT, United States, 5Radiology, Stanford, Stanford, CA, United States, 6Electrical Engineering, Stanford, CA, UT, United States

In this work, we improve upon previously reported values of T1 and T2* for sodium in the breast. Previously, we used a DESPOT1 sequence, whereas we have developed an inversion recovery sequence so that we can measure T1 values more accurately. For our healthy woman volunteer, we measured sodium T1 to be 39.0 ± 4.8 ms, T2long to be 21.0 ± 5.6 ms, and T2short to be 0.8 ± 0.4 ms.

15:00 3507.   Relaxation Time Measurements of 31P Metabolites in Human Muscle at 9.4 Tesla 
Yi Sui1,2, Haoyang Xing2, Theodore Claiborne2, Keith R Thulborn2,3, and Xiaohong Joe Zhou2,4
1Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 2Center for Magnetic Resonance Research, University of Illinois Medical Center, Chicago, IL, United States, 3Department of Radiology, University of Illinois Medical Center, Chicago, IL, United States, 4Departments of Radiology, Neurosurgery and Bioengineering, University of Illinois Medical Center, Chicago, IL, United States

In this study, we report multiple techniques to address the challenges of 31P relaxation measurements at 9.4 T. A Look-locker (LL) method was adapted for T1 measurement to shorten the total scan time. A two-tip-angle method was used to address the B1-field non-uniformity problem in the LL sequence. Additionally, quadratic-phase modulated RF pulses were employed to reduce RF peak amplitude without compromising the requirement of broad bandwidth of 31P spectrum at 9.4T. By strategically integrating these techniques, 31P relaxation times in human muscle have been determined accurately at 9.4 T within ~30 min.

Thursday May 12th
  13:30 - 15:30 Computer 48

13:30 3508.   Quantitative Sodium MRI with Fluid Suppression in the Knee Joint at 3T and 7T 
Guillaume Madelin1, Gregory Chang1, Alexej Jerschow2, and Ravinder R Regatte1
1Radiology Department, New York University Medical Center, New York, NY, United States, 2Chemistry Department, New York University, New York, NY, United States

This study demonstrates the feasibility of quantitative sodium MRI with fluid suppression in vivo in the knee joint at 3T and compares the results with that of 7T on the same 4 asymptomatic healthy volunteers. Two inversion recovery based methods (with a rectangular and an adiabatic pulse) for suppressing the fluids are also compared and show a good agreement at both fields. These preliminary results at 3T, despite their lower SNR and the small number of volunteers in this study, show slightly lower sodium concentration measurements but are still in good agreement with the data at 7T.

14:00 3509.   High Resolution Sodium MRI on Human Brain at 7T 
Yongxian Qian1, Tiejun Zhao2, Jonathan Weimer3, Hai Zheng3, and Fernando E Boada1,3
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States, 2R&D, Siemens Medical Solutions USA, Pittsburgh, PA, United States, 3Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States

The 7T scanners produce images of higher signal to noise ratio (SNR) than the 3T scanners and thus have potential to generate sodium images of higher spatial resolutions. This work demonstrates the feasibility of high-resolution (0.86mm) sodium imaging on human brain at 7T.

14:30 3510.   Sub-millimeter 23Na Imaging in Human Calf Skin at 7.0T 
Peter Linz1, Davide Santoro2, Wolfgang Renz2,3, Jan Ruff3, Jens Titze4, Friedrich Luft5, and Thoralf Niendorf2,5
1Department of Nephrology and Hypertension, University Clinic Erlangen-Nuernberg, Erlangen, Germany, 2Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, 3Siemens Healthcare, Erlangen, Germany, 4Department of Nephrology and Hypertension and Nikolaus-Fiebiger-Center for Molecular Medicine, University Clinic Erlangen-Nuernberg, Erlangen, Germany, 5Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany

We propose a dedicated 23Na coil to accomplish the first 23Na-MRI images of the skin with a sub-millimeter in plane resolution.

15:00 3511.   RARE imaging of post-exercise phospocreatine recovery - validation and reproducibility 
Robert L. Greenman1, Xiaoen Wang1, and Howard A. Smithline2
1Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, United States, 2Emergency Medicine, Bay State Medical Center, Tufts University School of Medicine, Boston and Springfield, MA, United States

The structure, blood flow patterns and metabolism have wide spatial variations in healthy individuals and are further modified in disease states and with physical training. Current methods cannot provide a simultaneous assessment of multiple muscle beds in a human limb. To address this need we have evaluated a phosphorus-31 MRI method for measuring the post-exercise recovery time constant of phosphocreatine in all of the muscles in a cross-section of the human leg. The method agrees very closely with the current standard method of phosphorus-31 MR spectroscopy and is highly reproducible.

Electronic Posters : Other
Click on to view the abstract pdf and click on to view the video presentation.
Hyperpolarized C13 I

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 49

14:00 3512.   Metabolism of Hyperpolarized [1-13C]Pyruvate in Isolated Perfused Mouse Livers – A Comparison of Fed and Fasted States 
Benjamin M. Pullinger1, Stephen J. Kadlecek1, Helen Chen2, Qingwei Chu2, Nicholas N. Kuzma1, and Rahim R. Rizi1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, United States

The metabolism of hyperpolarized [1-13C]pyruvate was investigated in the isolated perfused mouse liver. Along with the commonly observed conversions to alanine and lactate, we also observed pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC) activity. The ability to simultaneously measure PC and PDH flux has important implications in the study of insulin resistance. As a proof of concept, we report an increase in PC flux (0.17 plus-or-minus sign 0.03 to 0.30 plus-or-minus sign 0.06) in fasted livers compared to fed livers.

14:30 3513.   Detection of acute kidney injury using hyperpolarized [1,4-13C2]fumarate 
Mikko I Kettunen1, Menna R Clatworthy2,3, Timothy H Witney1, De-en Hu1, Brett W. C Kennedy1, Sarah E Bohndiek1, Rebeccah J Mathews2,3, Ferdia A Gallagher1,4, Ken G Smith2,3, and Kevin M Brindle1
1Department of Biochemistry, University of Cambridge & Cancer Research UK Cambridge Research Institute, Cambridge, Cambridgeshire, United Kingdom, 2Cambridge Institute for Medical Research, Cambridge, Cambridgeshire, United Kingdom, 3Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, Cambridgeshire, United Kingdom, 4Department of Radiology, Addenbrooke’s Hospital, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

Acute tubular necrosis (ATN) and glomerulonephritis (GN) are two common clinical forms of acute kidney injury with different treatment requirements. Currently, there is no non-invasive test to differentiate them. Here we exploited the appearance of malate signals following injection of hyperpolarized [1,4-13C2]fumarate to identify folate-induced ATN. Significantly increased malate signals were observed 18h after folate injection indicating increased necrosis. In contrast, malate signals were not increased in GN model despite the presence of proteinuria in both models. The results suggest hyperpolarized [1,4-13C2]fumarate is a potential non-invasive marker for separating ATN and GN.

15:00 3514.   Chemical Shift Selective Imaging of Hyperpolarized 13C Using Variable Phase Balanced Steady-State Free Precession 
Aaron Keith Grant1, Elena Vinogradov1, Xiaoen Wang1, Hao Wang1, Pankaj K Seth2, Vikas P Sukhatme2, David C Alsop1, and Robert E Lenkinski1
1Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 2Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States

13C spectra acquired after administration of hyperpolarized contrast media generally result in a relatively sparse collection of spectra lines. Several strategies that exploit this sparsity have been proposed for fast 13C spectroscopic imaging. Here we show that by acquiring a series of balanced steady-state free precession (bSSFP) images with a variable RF phase advance it is possible to obtain separate images of several metabolites. The method is illustrated using phantoms and in vivo studies with hyperpolarized pyruvate and t-butanol.

15:30 3515.   Super Stimulated-Echo Preparation for Hyperpolarized 13C Metabolic Imaging 
Peder Eric Zufall Larson1, Adam B Kerr2, Ralph E Hurd3, John Kurhanewicz1, John M Pauly2, and Daniel B Vigneron1
1Radiology and Biomedical Imaging, UC - San Francisco, San Francisco, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States,3Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States

Stimulated-echoes can be used to provide high sensitivity to diffusion and flow, creating unique contrast, but they inherently suffer from a 50% signal loss. The signal can be improved with a super stimulated-echo, which is more efficient. We have designed a new super stimulated-echo preparation scheme for diffusion and perfusion contrast in hyperpolarized 13C metabolic imaging. These have an expected 60% increase in SNR over a conventional stimulated-echo. By utilizing adiabatic pulse shapes in the preparation, they also have an improved response to B1+ variations. In vivo experiments in transgenic cancer mouse models have shown improved contrast for tumors.

Tuesday May 10th
  13:30 - 15:30 Computer 49

13:30 3516.   Transient decrease in tumor pO2 by 13C-pyruvate injection 
Keita Saito1, Shingo Matsumoto1, Nallathamby Devasahayam1, Sankaran Subramanian1, Jeeva P Munasinghe2, Jan Henrik Ardenkjaer-Larsen3, Herman Douglas Morris2, Martin J Lizak2, James B Mitchell1, and Murali C Krishna1
1National Cancer Institute, Bethesda, Maryland, United States, 2National Institute of Neurological Disorder and Stroke, 3GE Healthcare

MRI using hyperpolarized [1-13C]pyruvate is a promising tool for cancer diagnosis, but influences of exogenously injected pyruvate on tumor physiology were not well understood. Here, effects of pyruvate injection on tumor oxygen status were investigated using pulsed electron paramagnetic resonance imaging. Tumor pO2 was remarkably decreased 30 min after [1-13C]pyruvate injection. The pO2 decrease was transient, and the pO2 recovered to the pre-injection level 5 h after the pyruvate injection. This transient decrease in the pO2 influenced effects of X-irradiation: tumor growth suppression by X-irradiation was weakened when [1-13C]pyruvate was injected to mice 30 min before X-irradiation.

14:00 3517.   Metabolic Kinetics of a Glioma Model Using Hyperpolarized 13C Magnetic Resonance Spectroscopic Imaging 
Jae Mo Park1,2, Sonal Josan2,3, Taichang Jang4, Milton Merchant4, Yi-fen Yen5, Ralph Hurd5, Lawrence Recht4, Daniel Spielman1,2, and Dirk Mayer2,3
1Department of Electrical Engineering, Stanford University, Stanford, CA, United States, 2Department of Radiology, Stanford University, Stanford, CA, United States, 3SRI International, Menlo Park, CA, United States, 4Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States, 5Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States

In this work, we measured the kinetics of pyruvate metabolism in a glioma brain tumor model using the hyperpolarized 13C technique with a fast spiral CSI sequence, and compared the metabolic kinetics from three different ROIs: brain tumor, normal brain, and vasculature. Robust dynamic curves of Pyr and Lac were achievable repeatedly with 3 seconds of temporal resolution using the variable RF excitation angle on a single slice. The apparent rate constant of Pyr-to-Lac conversion in the brain tumor was noticeably higher than that in the normal brain and the vasculature.

14:30 3518.   Construction and Use of a Cryostat for Hyperpolarization Based on a 15 cm, 4.6 T Magnet 
Lloyd Lumata1, Richard Martin1, Ashish Jindal2, Zoltan Kovacs1, Craig Malloy1, A Dean Sherry1, Mark Conradi3, and Matthew E Merritt1
1AIRC, UTSW Medical Center, Dallas, TX, United States, 2UTSW Medical Center, United States, 3Physics, Washington University in St. Louis, St. Louis, MO, United States

In order to produce large volumes of highly polarized imaging agents, a DNP system based on a cryostat placed in an ultra widebore 4.6 T magent has been designed and implemented. The large available space allows a 600 ul sample cup to be used as well as an LN2 shield for the LHe bath. Operating at a 129 GHz ESR frequency and using nitrogen based radicals, samples with sufficient polarization for animal imaging are easily obtained. Total cost of the system was less than $100K, sans the cost of the magnet.

15:00 3519.   Fast volumetric imaging of ethanol metabolism in rat with hyperpolarized [1-13C]-pyruvate 
Sonal Josan1,2, Daniel Spielman2, Yi-Fen Yen3, Ralph Hurd3, Adolf Pfefferbaum1,4, and Dirk Mayer1,2
1SRI International, Menlo Park, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3GE Healthcare Applied Science Laboratory, Menlo Park, CA, United States, 4Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States

This work demonstrates time-resolved volumetric metabolic imaging of hyperpolarized [1-13C]-pyruvate using an undersampled spiral MRSI sequence, and applies it to investigate Pyr metabolism modulated by ethanol in rat liver. The dynamic 3D acquisition allows the analysis of spectra from organ-specific regions-of-interest, thus providing improved rate-constant estimates. Ethanol metabolism in the liver leads to accumulation of NADH which is a coenzyme in Pyr-to-Lac conversion. The apparent liver Pyr-to-Lac rate constants increased from pre- to post-ethanol, confirming the hypothesis that NADH levels are rate-limiting for liver Pyr-to-Lac conversion.

Wednesday May 11th
  13:30 - 15:30 Computer 49

13:30 3520.   Simultaneous Bloch-Siegert B1 mapping and imaging of hyperpolarized pyruvate, bicarbonate, and lactate, in a single tracer bolus 
Angus Zoen Lau1,2, Albert P Chen3, and Charles H Cunningham1,2
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 3GE Healthcare, Toronto, ON, Canada

Precise determination of transmit RF power (B1+) for 13C MR is challenging due to limited natural abundance of 13C in vivo. The phase-based Bloch-Siegert shift provides a B1 mapping method independent of Mz, making it possible to encode B1 in an image of hyperpolarized magnetization. Bloch-Siegert B1 mapping was implemented in a multi-slice interleaved 13C imaging pulse sequence. This study demonstrated the feasibility of simultaneously acquiring a B1 map and images of hyperpolarized [1-13C]pyruvate,13C bicarbonate, and [1-13C]lactate following a single tracer bolus of pre-polarized [1-13C]pyruvate and is anticipated to provide improved quantitative measurements of13C metabolism in vivo.

14:00 3521.   Investigating the Role of PDH Inhibition on the Development of Hypertrophy in the Hyperthyroid Rat Heart 
Helen J Atherton1,2, Michael S Dodd1, Lisa C Heather1, Marie A Schroeder1, Julian L Griffin2, George K Radda1, Kieran Clarke1, and Damian J Tyler1
1Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom, 2Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom

Hyperthyroidism, caused by an elevated level of thyroid hormones, leads to an increase in heart rate, contractility and cardiac output. Cardiac hypertrophy is another effect of hyperthyroidism and, although the hypertrophy is initially beneficial, it can lead to heart failure. The aim of this work was to determine whether alleviating the known inhibition of pyruvate dehydrogenase (PDH) in the hyperthyroid heart using dichloroacetate (DCA) would affect the response to hyperthyroidism. Using hyperpolarized MRS and CINE MRI, we found that DCA treatment increased PDH flux by 134% and significantly reduced the level of hypertrophy observed in the hyperthyroid rat heart.

14:30 3522.   Method for robust pH measurement using hyperpolarized bicarbonate and carbon dioxide 
Albert P Chen1, Ralph E Hurd2, Marie A Schroeder3,4, Angus Z Lau4,5, Yi-Ping Gu4, Wilfred W Lam4, and Charles H Cunningham4,5
1GE Healthcare, Toronto, ON, Canada, 2GE Healthcare, Menlo Park, CA, United States, 3Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom, 4Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 5Deptartment of Medical Biophysics, University of Toronto, Toronto, ON, Canada

To improve the robustness of pH measurement using hyperpolarized H13CO3- and 13CO2 signals in presence of carbonic anhydrase activity, the 13CO2 resonance was excited independently with a chemically selective RF pulse of larger tip-angle (to achieve higher SNR), while the other resonances of interest were acquired with a smaller tip angle. Accurate pH measurement could still be obtained even with repeated tipping (for temporally and/or spatially resolved data), since the ratio between the two pools was rapidly restored by the enzyme mediated exchange. This method was demonstrated in phantom and in vivo in pig heart.

15:00 3523.   Spectroscopic Imaging of Cerebral Metabolism using Hyperpolarized [1-13C]Pyruvate and Multi-echo Single-shot RARE sequence 
Peter Otto Magnusson1, Sadia Asghar Butt1, Mette Hauge Lauritzen1, Jan Henrik Ardenkjær-Larsen2, Per Åkesson1, and Lise Vejby Søgaard1
1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, 2GE Healthcare, Hillerød, Denmark

Efficient and rapid utilization of available magnetization is of greatest importance in hyperpolarized 13C MR since the in vivo decay time constant of the hyperpolarized signal is less than one minute. Here we demonstrate the potential of a multi-echo single-shot RARE sequence (FSEME) for rapid spectroscopic imaging of cerebral metabolism using HP [1-13C]Pyruvate. A FSEME-sequence was implemented and optimized and in vivo rat head 13C-scanning was conducted. Identification of cerebral sub-structures in metabolite maps from hyperpolarized [1-13C]Pyruvate in the rat brain was for the first time demonstrated using the rapid FSEME spectroscopic imaging sequence.

Thursday May 12th
  13:30 - 15:30 Computer 49

13:30 3524.   Autophagy induced by DCA treatment, PI3K inhibition or starvation results in reduced pyruvate to lactate exchange observed by DNP 13C-MRS. 
Yuen-Li Chung1, Gigin Lin1, Helen Troy1, Anne-Christine Wong Te Fong1, L E Jackson1, Deborah K Hill1, Matthew Orton1, Dow-Mu Koh1, Simon P Robinson1, Ian R Judson2, John R Griffiths3, Martin O Leach1, and Thomas R Eykyn1
1CR-UK & EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey, United Kingdom, 2CR-UK Centre for Cancer Therapeutics, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey, United Kingdom, 3Li Ka Shing Centre, CR-UK Cambridge Research Institute, Cambridge, United Kingdom

Autophagy is a cellular degradation response to starvation or stress whereby cellular proteins, organelles and cytoplasm are engulfed, digested and recycled to sustain cellular metabolism. We have investigated the effects of autophagy on TCA cycle activation using 1-13C-pyruvate DNP 13C-MRS. Autophagy was induced in three cancer cell lines by starvation, dichloroacetate and PI103 treatment. A significant reduction in the rate of labelled [1-13C] pyruvate to lactate exchange (and unpolarised lactate production) was associated with autophagy, rather than apoptosis or necrosis. A reduction in lactate production as measured by DNP 13C-MRS, and unchanged NAD+, may provide a non-invasive surrogate biomarker of autophagy.

14:00 3525.   Investigating tumor perfusion and metabolism using multiple hyperpolarized 13C compounds: HP001, urea, and pyruvate 
Cornelius von Morze1, Peder E Larson1, Simon Hu1, Robert Bok1, Hikari Yoshihara1, Andrei Goga2, Jan Henrik Ardenkjaer-Larsen3, and Daniel B Vigneron1
1Department of Radiology and Biomedical Imaging, UCSF, San Francisco, CA, United States, 2Department of Medicine, Division of Hematology / Oncology, UCSF, San Francisco, CA, United States, 3GE Healthcare, Hillerød, Denmark

The addition of perfusion information to metabolic information obtained by spectroscopic imaging of hyperpolarized [1-13C]pyruvate would be of great value in exploring links between perfusion and metabolism in cancer. We performed both dynamic imaging of the perfusion compound HP001, and co-polarized spectroscopic imaging of urea and pyruvate in preclinical murine cancer models. Spatially heterogenous perfusion was observed in the tumor tissues. A correlation between the urea and HP001 data confirmed the value of co-polarizing urea with pyruvate for simultaneous assessment of perfusion and metabolism.

14:30 3526.   Arterial input function by DNP measurement using an automated injector designed for a 7T unshielded magnet 
Steven Reynolds1, Samira Kazan2, Leigh Williams2, Aneurin Kennerley3, Jason Berwick3, Gillian Tozer2, and Martyn Paley1
1Academic unit of Radiology, Medical school, University of Sheffield, Sheffield, S. Yorkshire, United Kingdom, 2Department of Oncology, Medical school, University of Sheffield, Sheffield, S. Yorkshire, United Kingdom, 3Department of Psychology, University of Sheffield, Sheffield, S. Yorkshire, United Kingdom

Using the sensitivity enhancement of DNP we are using hyperpolarised pyruvate as a biomarker for changes in tumour oxygenation. To improve our model of the pyruvate metabolic flux we have measured the arterial input function (AIF) using the hyperpolarised 13C pyruvate signal from the carotid artery of a BDIX rat. Since AIF is dependent upon the injection condition there was a requirement to provide an automated, rapid, injection system. We have developed an automated injector that can be used close the bore of an unshielded 7T magnet.

15:00 3527.   Efficient preparation of hyperpolarized aqueous succinate from the para-hydrogenation and hydrolysis of maleic anhydride 
Francesca Reineri1, Alessandra Viale1, Silvano Ellena1, Tommaso Boi1, Roberto Gobetto1, and Silvio Aime1
1University of Torino, Torino, IT, Italy

Para-Hydrogen Induced Polarization (PHIP) has been recently exploited for the preparation of hyperpolarized 13C contrast agents for MRI. For the observation of large PHIP effects the use of homogeneous hydrogenation catalysts is generally required. The catalyst and (if present) the organic solvent must then be removed in order to obtain non-toxic formulations of the hyperpolarized agents. Here we report the para-hydrogenation of an unsaturated activated substrate, maleic anhydride, in chloroform, followed by rapid hydrolysis to form a water-soluble derivative, succinic acid, which can be extracted in water to yield a pure aqueous solution of the hyperpolarized molecule.

Click on to view the abstract pdf and click on to view the video presentation.
Electronic Posters : Other
Hyperpolarized C13 II

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 50

14:00 3528.   Effects of RF excitation scheme on signal-to-noise-ratio and apparent rate constant estimation in dynamic volumetric imaging of hyperpolarized [1-13C]-pyruvate 
Sonal Josan1,2, Ralph Hurd3, Adam B Kerr4, Yi-Fen Yen3, Peder E.Z. Larson5, Adolf Pfefferbaum1,6, Daniel Spielman2, and Dirk Mayer1,2
1SRI International, Menlo Park, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3GE Healthcare Applied Science Laboratory, Menlo Park, CA, United States, 4Electrical Engineering, Stanford University, Stanford, CA, United States, 5Dept of Radiology and Biomedical Imaging, UC-San Francisco, San Francisco, CA, United States, 6Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States

Dynamic 3D metabolic imaging of hyperpolarized [1-13C]-pyruvate requires a large number of RF excitations, which can impact the shape of the dynamic response, the calculation of apparent rate constants, and signal to noise ratio. This work investigates the performance of different flip angle schemes using multi-band RF pulses in multiple organs (brain, liver and kidney) with different tissue perfusion rates and metabolic activities.

14:30 3529.   Dynamic imaging of hyperpolarized [2-13C] pyruvate and [5-13C] glutamate in the heart 
Angus Zoen Lau1,2, Albert P Chen3, Marie A Schroeder4, Jennifer Barry2, and Charles H Cunningham1,2
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 3GE Healthcare, Toronto, ON, Canada, 4Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom

We demonstrate the feasibility of imaging hyperpolarized [2-13C] pyruvate and its major observable Krebs cycle metabolite, [5-13C] glutamate, in the heart, using a cardiac and respiratory-gated imaging pulse sequence in vivo (TR 2.5s, 2 slices, 30mm in-plane resolution). A spectral-spatial RF excitation was designed to selectively excite either C2 pyruvate or C5 glutamate, while avoiding excitation of the remaining resonances in the spectrum. The sequence is demonstrated in vivo in pig hearts and provides a method to measure spatially dependent changes in Krebs cycle metabolism in vivo.

15:00 3530.   Localized in vivo hyperpolarization transfer experiments 
Mor Mishkovsky1,2, Tian Cheng1, Rolf Gruetter1,3, and Arnaud Comment1,2
1Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Department of Radiology, Université de Lausanne, Lausanne, Switzerland, 3Department of Radiology, Universités de Lausanne et de Genève, Lausanne and Genève, Switzerland

In vivo localized and fully adiabatic homo- and hetero-nuclear polarization transfer experiments were designed and performed in the rat brain at 9.4T after infusion of hyperpolarized 13C2 and 1-13C sodium acetate solutions. The new scheme presented herein allows for highly enhanced in vivo detection of nuclear spins with short T1’s, including protons, thus bringing new spectroscopic information on hyperpolarized substrates and their metabolites. In addition, in cases of narrow spectral dispersion, indirect detection can improve the spectral resolution such as in the case of 1-13C acetate of 15N choline metabolism.

15:30 3531.   Single-shot, Frequency and Time Specific, 3D Imaging Method for Measuring Hyperpolarized 13C Biomarkers In-Vivo at 14.1 Tesla 
Subramaniam Sukumar1, Kayvan R Keshari1, Robert Bok1, Vickie Zhang1, Andrew Taylor1, Michael A Ohliger1, Hikari Yoshihara1, John Kurhanewicz1, and Daniel B Vigneron1
1Radiology and Biomedical Imaging, UCSF, San Francisco, CA, United States

Hyperpolarized 13C biomarkers provide unique biochemical information in-vivo but the short lived magnetization requires special pulse sequences for acquiring the MRSI data quickly and efficiently. High field systems pose further challenges because artifacts related to wide chemical shift dispersion, T2* and motion are increased. We developed a novel, single shot, chemical shift specific 3D imaging method which is particularly suited for high field studies involving hyperpolarized 13C biomarkers. We have used the technique for studying various disease models in mice at 14.1T.

Tuesday May 10th
  13:30 - 15:30 Computer 50

13:30 3532.   Free-breathing cardiac and respiratory-gated imaging of hyperpolarized pyruvate and bicarbonate in the heart 
Angus Zoen Lau1,2, Albert P Chen3, Marie A Schroeder2,4, Wilfred W Lam2, Yiping Gu2, Jennifer Barry2, and Charles H Cunningham1,2
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 3GE Healthcare, Toronto, ON, Canada, 4Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom

We incorporate respiratory gating into a rapid multi-slice single-shot cardiac 13C imaging pulse sequence. This provides time-resolved imaging of hyperpolarized [1-13C]pyruvate, [1-13C]lactate, and 13C bicarbonate in vivo (TR 2.5s, 2 slices, 9 mm in-plane resolution), allowing for capture of the first pass of the tracer bolus and images of downstream metabolites at later times after they have appeared. The sequence is demonstrated in vivo in pig hearts and may provide improved quantitative measurements of 13C metabolism in vivo.

14:00 3533.   Improving estimation of intracellular hyperpolarized 1-13C-pyruvate kinetics by co-injection of gadolinium contrast agent 
Matthew Smith1, Eric Peterson2, Jeremy Gordon1, Kang Wang1, Ian Rowland3, and Sean Fain1,3
1Medical Physics, University of Wisconsin, Madison, WI, United States, 2Biomedical Engineering, University of Wisconsin, Madison, WI, United States, 3Radiology, University of Wisconsin, Madison, WI, United States

Hyperpolarized 13C-labeled pyruvate studies with MR have been used to observe the dynamic 13C label transfer to other metabolites. In this work, we first investigate the limitations of kinetic modeling of the in-vivo 13C label transfer using a widely used two-site exchange model and demonstrate a novel technique to provide contrast to the intracellular compartment by injecting a Gd-chelate following the injection of HP 13C-pyruvate to provide T1-shortening to non-intracellular compartments. We also provide a kinetic model that distinguishes the intracellular space by utilizing this contrast.

14:30 3534.   Hyperpolarized Water for Interventional Angiography 
Jan Henrik Ardenkjaer-Larsen1, Christoffer Laustsen2, Benjamin Pullinger3, Stephen Kadlecek3, Kiarash Emami3, and Rahim Rizi3
1GE Healthcare, Broendby, Denmark, 2DRCMR, Hvidovre, Denmark, 3University of Pennsylvania, United States

We demonstrate a novel method of hyperpolarizing water based on the dissolution-DNP method. The method has several advantages: a) very high polarization (tens of percent) and b) long relaxation times (by dilution in D2O). A magnetization equivalent to more than 70 T is demonstrated in phantoms. The applicability of the method is demonstrated in the rat by several angiographic acquisitions.

15:00 3535.   Interrogating Tricarboxylic Acid Cycle: A Comparative Study by Hyperpolarized Succinic Acid and its Diethylester 
Pratip Bhattacharya1, Niki Zacharias1, Henry Chan1, Napapon Sailasuta1, Larry W Robertson1, Alan Epstein2, and Brian D Ross1
1Enhanced MR Laboratory, Huntington Medical Research Institutes, Pasadena, CA, United States, 2Pathology, University of Southern California, Los Angeles, CA, United States

The goal of this work is to interrogate the succinate level in the cytosol by hyperpolarization of succinate, a key metabolite of Tricarboxylic Acid Cycle (TCA) and its diethyl ester derivate. Succinate Dehydrogenase (SDH)-catalyzes the oxidation of succinate to fumarate with the reduction of ubiquinone to ubiquinol and is an oncogene defined in many cancers. Here we demonstrate different metabolic profiles in vivo using two molecules with slight variations but with very different uptake rates. Hyperpolarized diethyl ester of succinic acid (diethylsuccinate) is taken up rapidly in vivo in both normal and tumor bearing mice, while hyperpolarized succinic acid is apparently taken up only in some tumor bearing animals. The results underscore the importance of chemical modification in choosing molecular targets to achieve desired metabolic imaging using hyperpolarization.

Wednesday May 11th
  13:30 - 15:30 Computer 50

13:30 3536.   Study of acetyl carnitine kinetics in skeletal muscle in vivo using hyperpolarized 1-13C acetate 
Jessica A M Bastiaansen1, Tian Cheng1, Mor Mishkovsky1,2, Arnaud Comment1,2, and Rolf Gruetter1,3
1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Department of Radiology, Université de Lausanne, Lausanne, Switzerland, 3Department of Radiology, Université de Lausanne et Genève, Lausanne and Geneva, Switzerland

Carnitine plays a vital role in the regulation of muscle fuel metabolism and buffers mitochondrial acetyl CoA via rapid conversion into acetyl carnitine. Hyperpolarized 13C MR offers the possibility to directly monitor acetyl carnitine kinetics and provides significant new information about its metabolism. Herein, we studied acetyl carnitine kineticsin vivo following injections of hyperpolarized 1-13C acetate. Using a one site exchange metabolic model, we investigated acetyl carnitine formation in skeletal muscle in vivo and determined its kinetics to provide a paradigm for future studies involving altered pathology.

14:00 3537.   Spectral-spatial EPI sequence with frequency correction for dynamic 3D imaging of pre-polarized 13C metabolites 
Charles H. Cunningham1,2, Ralph E. Hurd3, and Albert P. Chen4
1Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3GE Healthcare, Menlo Park, CA, United States, 4GE Healthcare, Toronto, ON, Canada

Motivated by the need for 3D metabolic images at multiple timepoints, a rapid spectral-spatial echo-planar imaging (ss-epi) pulse sequence tailored for clinical application was developed. The feasibility of using registration of consecutive metabolic images as a method for measuring and correcting the frequency-induced spatial shifts that occur in vivo was investigated. In experiments with rats and hyperpolarized [1-13C] pyruvate, excellent image quality and apparent agreement with the underlying anatomy was observed. The frequency correction method was shown to have an accuracy of 3 Hz.

14:30 3538.   Producing >60,000-fold room-temperature 89Y NMR signal enhancement 
Lloyd Laporca Lumata1, Ashish Jindal1, Matthew Merritt1, Craig Malloy1, Allan Dean Sherry1,2, and Zoltan Kovacs1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 2Department of Chemistry, University of Texas at Dallas, Richardson, Texas, United States

We present optimization studies of hyperpolarized 89Y NMR signal which shows a relatively long polarization lifetime T1~500 s. Liquid-state 89Y NMR signal enhancement as high as 65,000 times the thermal signal, which corresponds to a polarization of 10 %, has been achieved at room temperature in a 9.4 T magnet after dynamic nuclear polarization of Y-DOTA samples at 3.35 T and 1.4 K. The 89Y NMR enhancement is optimized by varying the glassing matrices and paramagnetic agents as well as doping the samples with a gadolinium relaxation agent. The high room-temperature NMR signal enhancement places 89Y, one of the most difficult nuclei to do NMR spectroscopy, in the list of viable magnetic resonance imaging (MRI) agents when hyperpolarized under optimized conditions.

15:00 3539.   In vivo assessment of metabolism in the hypertensive rat heart using hyperpolarized [1-13C] and [2-13C]pyruvate 
Michael Samuel Dodd1,2, Daniel Ball1, Marie A Schroeder1, Helen J Atherton1, Lydia Le Page1, George K Radda1, Houman Ashrafian2, Hugh Watkins2, Kieran Clarke1, and Damian J Tyler1
1Physiology, Anatomy and Genetics, Oxford University, Oxford, United Kingdom, 2Cardiovascular Medicine, Oxford University, Oxford, United Kingdom

Spontaneously hypertensive rats (SHRs) display hypertension, insulin resistance and concentric hypertrophy. There is hypothesised to be a switch to a glycolytic phenotype in SHRs. Using hyperpolarized magnetic resonance spectroscopy, via dynamic nuclear polarization, the metabolism of [1-13C] and [2-13C]pyruvate was observed. This showed a 63% increase in PDH flux in SHRs and an increase in label incorporation into acetylcarnitine and glutmate pools, which is proportional to the increase in PDH flux. No classical switch to a glycolytic phenotype was observed, as flux into lactate remained unchanged between groups. However, an increased reliance on glucose oxidation through PDH, was observed.

Thursday May 12th
  13:30 - 15:30 Computer 50

13:30 3540.   In vivo localized 15N MRS detection of hyperpolarized 15N labeled choline in the rat brain 
Cristina Cudalbu1, Arnaud Comment1, Tian Cheng1, Mor Mishkovsky1, and Rolf Gruetter1,2
1Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Departments of Radiology, Universities of Lausanne and Geneva, Geneva, Switzerland

We acquired localized in vivo hyperpolarized 15N Cho spectra using two different voxel sizes in order to investigate the spatial origin of the 15N Cho signal in the rat brain. In the small voxel where the major blood vessels contribution should be negligible, the in vivo 15N Cho signal was visible for more than 1 min. To our knowledge the in vivo localized detection of hyperpolarized 15N has not been demonstrated to date.

14:00 3541.   Evaluation of Heterogeneous Metabolic Profile in an Orthotopic Human Glioblastoma Xenograft Model Using 3D Compressed Sensing Hyperpolarized 13C MRSI 
Ilwoo Park1, Simon Hu1, Robert Bok1, Peter Shin1, Tomoko Ozawa2, C. David James2, Sabrina M Ronen1, Daniel B Vigneron1,3, and Sarah J Nelson1,3
1Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States,2Brain Tumor Research Center, Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States, 3Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, United States

We modified a previous compressed sensing scheme and acquired hyperpolarized 13C 3D MRSI data from an orthotopic human xenograft tumor model in rat brain. The 3.72-fold acceleration factor allowed the reliable acquisition of hyperpolarized 13C 3D MRSI data with 4 times better resolution in approximately the same scan time compared to the fully sampled data. The new sequence was applied to evaluate heterogeneous metabolic profiles within the tumor tissue of rats with brain cancer. The results from this study suggest that this technique may be used to differentiate brain tissue with different tumor histology.

14:30 3542.   Exchange Dynamics of a Cryptophane-based Xenon Molecular Sensor 
Richard Matthew Ramirez1,2, Todd K Stevens1,2, Monica A Smith3,4, David E Wemmer1,4, and Alexander Pines1,2
1Department of Chemistry, University of California, Berkeley, Berkeley, CA, United States, 2Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States, 3Biophysics Graduate Group, University of California, Berkeley, United States, 4Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States

The exchange dynamics of a xenon molecular sensor based on cryptophane-A were elucidated by modeling the signal decay generated by (CEST) against the McConnell-Bloch equations to determine xenon dissociation rates from cryptophane-A

15:00 3543.   Detection of Glutaminase Activity In Vivo in a MYC Mouse Model of Liver Cancer Using Hyperpolarized [5-13C]Glutamine 
Simon Hu1, Hikari Yoshihara1, Robert Bok1, Asha Balakrishnan2, Andrei Goga2, John Kurhanewicz1, and Daniel B Vigneron1
1Dept. of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, United States, 2Dept. of Medicine, Division of Hematology/Oncology, University of California at San Francisco, San Francisco, CA, United States

Development of hyperpolarized technology utilizing dynamic nuclear polarization has enabled the measurement of 13C metabolism in vivo at very high SNR. In this work, hyperpolarized [5-13C]glutamine was used to probe glutaminase activity in vivo in a MYC oncogene driven liver cancer mouse model and in normal mice. Slab-localized spectra were obtained, and the areas associated with glutamine and glutamate peaks were quantified. A significant increase in glutamate to glutamine ratio (P = 0.0021) was detected in liver tumor versus normal tissue. MYC transcription has been linked with increased glutamine catabolism, a phenomenon termed glutamine addiction, which is consistent with the increased glutaminase activity we observed.