Kyung Min Nam¹, Ayhan Gursan¹, Alex Bhogal¹, Jannie Wijnen¹, Dennis Klomp¹, Jeanine Prompers¹, and Arjan D. Hendriks^1
1University of Medical Center Utrecht, Utrecht, Netherlands

Deuterium Echo-Planar Spectroscopic Imaging (DEPSI) is proposed as a way to increase the spatial and temporal resolution of deuterium metabolic imaging (DMI) at 7T. Typically, DMI uses traditional, slow MRSI sequences, which cannot capture rapid dynamic metabolic processes in large organs with sufficient spatial and/or temporal resolution. With DEPSI, in vivo glucose metabolism of the liver could be monitored after intake of [6,6′-²H₂]-glucose with 20 mm nominal voxel size, full liver coverage, and a scan time of less than 10 minutes. DEPSI was combined with Hamming weighted acquisition in the phase encoding directions to maximize SNR.

Stefan Markovic¹, Tangi Roussel², Michal Neeman³, and Lucio Frydman^1
1Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel, ²Center for Magnetic Resonance in Biology and Medicine, Marseille, France, ³Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel

Deuterium Metabolic Imaging (DMI) was used to follow metabolism in wildtype and l-NAME induced preeclamptic pregnant mice, after intravenous administration of ²H_6,6’-glucose. Maps for ²H_6,6’-glucose and its metabolic products ²H_3,3’-lactate and ²H-water were measured over 2 hours by ²H CSI at 15.2 tesla. ²H-water was generated as main metabolic product in fetoplacental units; placentas and fetal organs also generated ²H_3,3’-lactate, but this was not detected in other maternal organs. Lactate levels were more elevated and its clearance was slower in preeclamptic fetuses than in healthy controls. DMI thus may aid in development and monitoring of future intervention for early preeclampsia.

Yaewon Kim¹, Brian T. Chung¹, Jeremy W. Gordon¹, Adam W. Autry¹, Chou T. Tan², Chris Suszczynski², Susan M. Chang³, Yan Li¹, Duan Xu¹, and Daniel B. Vigneron^1,3
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, United States, ²ISOTEC Stable Isotope Division, MilliporeSigma, Merck KGaA, Miamisburg, OH, United States, ³Department of Neurological Surgery, University of California, San Francisco, CA, United States

Hyperpolarized (HP) [2-¹³C]pyruvate MRI has great clinical potential for monitoring pyruvate-to-glutamate conversions through the TCA cycle in addition to pyruvate-to-lactate glycolytic metabolism. This new method for human molecular imaging has enabled whole brain acquisitions with sufficient signal-to-noise. Using a specialized multi-slice EPI sequence, volumetric, dynamic images of HP [2-¹³C]pyruvate and its downstream metabolites [5-¹³C]glutamate and [2-¹³C]lactate were acquired from healthy brain volunteers. The downfield and upfield lactate signals were acquired separately with no artifacts arising from J-coupling were observed. This work demonstrated the capability of volumetric and dynamic [2-¹³C]pyruvate EPI to interrogate both glycolytic and oxidative cerebral energy metabolism simultaneously.

Hecong Qin^1,2, Shuyu Tang¹, Andrew Riselli¹, Robert A. Bok¹, Romelyn Delos Santos¹, Mark Van Criekinge¹, Jeremy W. Gordon¹, Rahul Aggarwal³, Evelyn Escobar¹, Rui Chen⁴, Chunxin Tracy Zhang⁵, Gregory Goddard⁵, Albert Chen⁴, Galen Reed⁴, Ruscitto M. Daniel⁵, Renuka Sriram¹, James Slater¹, Peder E.Z. Larson^1,2, Daniel B. Vigneron^1,2, and John Kurhanewicz^1,2
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, ²Graduate Program in Bioengineering, UC Berkeley – UCSF, San Francisco, CA, United States, ³Medicine, University of California, San Francisco, San Francisco, CA, United States, ⁴GE Healthcare, Waukesha, WI, United States, ⁵GE Research, Niskayuna, NY, United States

Altered metabolism and perfusion are implicated in cancer’s underlying pathophysiology. Prior preclinical and clinical studies have shown that metabolic and perfusion imaging could provide a sensitive and specific evaluation of tumor grade and therapeutic response. We aim to develop a dual-agent hyperpolarized ¹³C MR technique for simultaneous metabolic and perfusion imaging in humans. Here, we report the technical developments towards its clinical translation: 1) formulation and co-polarization system of ¹³C pyruvate and urea, 2) imaging probe characterization, 3) safety-related studies, and 4) multi-probe imaging sequence. Upon FDA approval, this work would lead to the first-in-human dual-agent hyperpolarized MR study. 

Hannes Michel Wiesner¹, Rong Guo^2,3, Yudu Li^2,3, Yibo Zhao^2,3, Zhi-Pei Liang^2,3, Xiao-Hong Zhu¹, and Wei Chen^1
1CMRR, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, ²Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ³Departments of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States

In vivo ³¹P MRS imaging (MRSI) is unique to study brain energy metabolism including ATPase and creatine kinase metabolic rates, and the NAD redox ratio especially at ultrahigh field (UHF) with significant improvements in detection sensitivity and spectral resolution. Nevertheless it is still challenging to achieve high spatial resolution even at UHF, owing to extremely low concentration of phosphorus metabolites. In this study, we employed the subspace‐based image reconstruction method called SPICE to largely reduce spectral noise and increase the signal-to-noise ratio (SNR) for achieving high-resolution 3D ³¹P MRSI covering the entire human brain at 7T.

Julia J Gevaert^1,2, Corby Fink^3,4, Jimmy D Dikeakos³, Gregory A Dekaban^3,4, and Paula J Foster^1,2
1Department of Medical Biophysics, University of Western Ontario, London, ON, Canada, ²Cellular and Molecular Imaging Group, Robarts Research Institute, London, ON, Canada, ³Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada, ⁴Biotherapeutics Research Laboratory, Robarts Research Institute, London, ON, Canada

The purpose of this study was to explore magnetic particle imaging (MPI), which directly detects superparamagnetic iron oxide nanoparticles (SPIOs) as a novel technique for tracking dendritic cells (DCs). DCs were labeled using Vivotrax, a commonly used MPI-SPIO, and Synomag-D, a tailored MPI-SPIO, with and without transfection agents. Vivotrax with TAs showed high levels of extracellular iron, overestimating iron content and cellular sensitivities. The use of TAs improved cellular sensitivity of Synomag-D to as few as 6k cells with 1min 2D images. Signal from 250k and 25k cells could be resolved at a distance of 2cm with 3D imaging.

Solène Bardin^1,2, Michele Lecis^1,3, Davide Boido^1,2, Fawzi Boumezbeur^1,2, and Luisa Ciobanu^1,2
1NeuroSpin, CEA, Gif-sur-Yvette, France, ²Paris-Saclay University, Saclay, France, ³Technical University of Munich, Munich, Germany

Accelerated CEST acquisitions using a linescan sequence coupled with an ultra-high magnetic field allows, for the first time, the detection of carnosine in vivo.

Anna K. Scheipers¹, Johanna Lott¹, Armin M. Nagel^1,2, Peter Bachert¹, Mark E. Ladd¹, and Tanja Platt^1
1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, ²University Hospital Erlangen, Institute of Radiology, Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU), Erlangen, Germany

Sodium (²³Na) plays an important role in many cellular processes, making it an interesting nuclei to investigate using MRI. Low in-vivo signals and short relaxation times require high magnetic field strengths, dedicated hardware and pulse sequences as well as correction methods to obtain reliable tissue sodium concentrations. Therefore we compare the influence of different correction methods on ²³Na concentration investigations in the human kidney and validate our methods with phantom measurements. We employ retrospective respiratory self‐gating for the quantitative ²³Na images as well as for the acquired B₁⁺ maps to reduce the influence of image blurring due to motion artifacts.

Anna M Chen¹, Teresa Gerhalter¹, Seena Dehkharghani^1,2, Rosemary Peralta¹, Fatemeh Adlparvar¹, James S Babb¹, Tamara Bushnik³, Jonathan M Silver⁴, Brian S Im³, Stephen P Wall⁵, Ryan Brown^1,6, Steven Baete^1,6, Ivan I Kirov^1,2,6, and Guillaume Madelin^1
1Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States, ²Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States, ³Department of Rehabilitation Medicine, New York University Grossman School of Medicine, New York, NY, United States, ⁴Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, United States, ⁵Ronald O. Perelman Department of Emergency Medicine, New York University Grossman School of Medicine, New York, NY, United States, ⁶Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States

27 mTBI patients and 19 controls were scanned at 3T. Total sodium concentration (TSC), fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured with voxel averaging in 12 grey and white matter regions-of-interest (ROIs). Patients had lower mean TSC than controls across all ROIs, however, statistical significance was only reached in the caudate. Statistically significant FA differences also occurred in only one region, frontal white matter (WM), while none were observed for ADC. TSC changes existed in mTBI and occurred with similar frequency as FA, but the FA finding had a higher effect size, and correlated with symptoms.

Zidan Yu^1,2, Olga Dergahyova¹, Daniel K. Sodickson^1,2, Guillaume Madelin^1,2, and Martijn A. Cloos^3,4
1Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, ²Vilcek Institute of Graduate Biomedical Sciences, NYU Langone Health, New York, NY, United States, ³Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia, ⁴ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, Brisbane, Australia

In this work, we present an optimized 3D technique that can simultaneously acquire quantitative ¹H density, T₁, T₂, B₁⁺ maps and a ²³Na image of the whole head in a reasonable scan time (~20 min).