|
| 5076.
 | Feasibility of Volumetric Multiple-Breath Washout 19F-Perfluoropropane Ventilation Mapping of the Lung in Healthy Children Faiyza Shoaib Alam1,2, Brandon Zanette2, Daniel Li2, Sharon Braganza2, Mary A. Neal3, Peter E. Thelwall3, Felix Ratjen2,4, and Giles Santyr1,2
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada, 3Newcastle University, Newcastle upon Tyne, United Kingdom, 4Division of Respiratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada Keywords: Non-Proton, Pediatric, lung Motivation: Multiple-breath washout (MBW) MRI following exhalation of a tracer gas results in regional maps of fractional ventilation (FV). Using perfluoropropane (PFP) gas allows for long washout experiments which may provide useful clinical insight on slow-filling regions of diseased lungs, particularly in children. Goal(s): Test feasibility of MBW PFP-MRI in pediatric healthy participants, investigate gravitational dependence of FV. Approach: 3 healthy pediatric participants were imaged using 3D broad-banded 19F-MRI and the following MBW maneuver: 6 inhalations of PFP gas mixture, then wash-out with room air with 8s MR-images every second breath. Results: MBW PFP-MRI was feasible in children. The gravitational gradient was as expected. Impact: The ability of PFP to be mixed with oxygen and the
fact that it is thermally polarized makes longer MBW studies possible and thus
has the potential to improve tolerance by younger subjects and those with more
advanced lung disease. |
| 5077.
 | The effect of [6,6'-2H2]glucose dose on human brain deuterium metabolic imaging at 7T Narjes Ahmadian1, Maaike Konig2, Mark Gosselink2, Ayhan Gursan2, Sigrid Otto3, Kiki Tesselaar3, Pieter van Eijsden4, Dennis Klomp2, Jeanine Prompers2, and Evita Wiegers2
1Radiology and Neurosurgery, UMC Utrecht, Utrecht, Netherlands, 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 3CTI Lab support, University Medical Center Utrecht, Utrecht, Netherlands, 4Neurosurgery, University Medical Center Utrecht, Utrecht, Netherlands Keywords: Deuterium, Spectroscopy Motivation: Deuterium metabolic imaging (DMI) is used to study metabolic processes, but the effect of varying substrate doses on DMI data in the brain is not yet known Goal(s): Comparing different doses aims to reduce cost, while still achieving sufficient sensitivity for DMI Approach: Three healthy participants received different doses of [6,6'-2H2]glucose on two occasions and underwent dynamic 7T DMI scans Results: In 120-minutes after ingesting [6,6'-2H2]glucose , there is no clear difference in the signal of 2H-glucose/2H-Glx in the brain between the 0. 50-0.75g/kg doses. However, there was an earlier decrease in the signal when using the 0.25g/kg dose in one subject. Impact: We
compared three different doses [6,6'-2H2]glucose
for Deuterium Metabolic Imaging of the
brain, at 7T. Metabolite signals were
comparable for the 0.50g/kg and 0.75g/kg doses, making 0.50g/kg a potential
cost-saving alternative for clinical translation. |
| 5078.
 | Comparison of Deuterium Metabolic Imaging and FDG-PET in Alzheimer’s Disease Nikolaj Bøgh1, Malene Aastrup1, Janne K Mortensen2, Hanne Gottrup 2, Jakob Blicher 3, Rolf F Schulte4, Per Borghammer1, Mattias Hedegaard Kristensen 1, Esben Søvsø Szocska Hansen1, Michael Vaeggemose1,4, and Christoffer Laustsen1
1Aarhus University, Aarhus, Denmark, 2Aarhus University Hospital, Aarhus, Denmark, 3Aalborg University Hospital, Aalborg, Denmark, 4GE Healthcare, Munich, Germany Keywords: Deuterium, Deuterium Motivation: Distinguishing Alzheimer’s Disease form other dementias is becoming increasingly important with the development of amyloid-targeting therapies. This requires extensive clinical and paraclinical work-up, often including structural and molecular brain imaging. Goal(s): To compare deuterium metabolic imaging (DMI) with routinely used clinical imaging technologies for the detection of Alzheimer’s Disease. Approach: We performed a prospective clinical trial of 5 healthy age-matched controls compared with 10 patients Alzheimer’s dementia. Results: Deuterium metabolic imaging showed decreased metabolism in temporal and parietal brain regions in patients with Alzheimer’s disease compared with healthy controls. This hypometabolic pattern correlated well with FDG-PET. Impact: This preliminary study suggests that metabolic imaging in suspected dementia may be performed with DMI. This would allow simultaneous imaging of structural, vascular, and metabolic changes at a cost comparable to FDG-PET. |
| 5079.
 | Physiological Interpretation of the AUC Ratio for Hyperpolarized [1-13C]-Pyruvate Ryan Boyce1,2, Collin Harlan1,3, Qing Wang1, and James Bankson1,3
1Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, TX, United States, 2Department of Physics, University of Houston, Houston, TX, United States, 3UTHealth Graduate School of Biomedical Sciences, University of Texas MD Anderson Cancer Center, Houston, TX, United States Keywords: Hyperpolarized MR (Non-Gas), Modelling Motivation: The prevalence of the use of AUC ratio as a metric of anaerobic respiration in hyperpolarized pyruvate studies motivates a careful examination of its physiological interpretation. Goal(s): We seek to characterize the lactate to pyruvate AUC ratio as a surrogate for aerobic glycolysis in cancer cells. Approach: A simplified three-compartment kinetic model is proposed and analyzed. The AUC ratio is found from the model for interpretation. Results: The simplified three-compartment model is shown to produce equivalent time curves to the full model. The AUC ratio, parametrized by the simplified model, varies non-linearly with the rate of intracellular lactate production. Impact: The
efficacy of hyperpolarized pyruvate as a probe of tumor metabolism relies on an
accurate and reproducible quantification and interpretation of acquired signal. We critically examine one of the most commonly used methods of signal
interpretation in hyperpolarized pyruvate studies. |
| 5080.
 | In Vivo Imaging of Tumor Metabolic Heterogeneity Using [1-13C]Pyruvate-d3 Hyperpolarized By Reversible Exchange With Parahydrogen Stefan Petersen1, Philipp Groß1,2, Luca Nagel3, Robert Willing1,2, Lisa Heß4, Julia Mitschke4, Nicole Klemm4, Christoph A. Müller5, Stephan Knecht5, Moritz Weigt1, Michael Bock1, Dominik von Elverfeldt1, Maxim Zaitsev1, Eduard Y. Chekmenev6, Jan-Bernd Hövener7, André F. Martins8,9, Franz Schilling3,10, Thomas Reinheckel2,4, and Andreas B. Schmidt1,2,6
1Division of Medical Physics, Department of Diagnostic and Interventional Radiology, Faculty of Medicine, University of Freiburg, University Medical Center Freiburg, Freiburg 79106, Germany, 2German Cancer Consortium (DKTK), partner site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany, 3Department of Nuclear Medicine, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich 81675, Germany, 4Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg 79104, Germany, 5NVision Imaging Technologies GmbH, Ulm 89081, Germany, 6Department of Chemistry, Integrative Biosciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit 48202, MI, United States, 7Sektion Biomedizinsche Bildgebung, Molecular Imaging North Competence Center MOINCC, Klinik für Radiologie und Neuroradiologie, University Hospital Schleswig-Holstein, Kiel University, Kiel, Germany, 8Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen 72076, Germany, 9German Cancer Consortium (DKTK), partner site Tübingen, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany, 10German Cancer Consortium (DKTK), partner site Munich, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany Keywords: Hyperpolarized MR (Non-Gas), Contrast Agent Motivation: Hyperpolarized [1-13C]pyruvate MRI is promising for studying cancer metabolism and assessing early therapy response but requires high-throughput and less complex hyperpolarization techniques for wide availability. Goal(s): Demonstrating metabolic imaging in a genetic mouse model of metastasizing breast cancer (MMTV-PyMT) using purified [1-13C]-pyruvate-d3 hyperpolarized via parahydrogen-based Signal Amplification By Reversible Exchange (SABRE). Approach: Our rapid (6 min) and efficient hyperpolarization method yielded highly-polarized (>10%) [1-13C]-pyruvate-d3 in safe aqueous solutions. Results: Administered to two PyMT-mice, 13C chemical shift imaging detected the injected pyruvate and metabolized [1-13C]-lactate. Analysis revealed elevated lactate levels in tumors compared to healthy breast tissue, highlighting tumor compartments with distinct metabolic profiles. Impact: We showcase our rapid, cost-effective SABRE hyperpolarization approach, yielding safe, highly-polarized pyruvate for inaugural cancer metabolic investigations. This innovation expands high-throughput preclinical HP-MRI research, enabling comprehensive exploration of tumor biology, metabolic processes, and therapeutic responses in cancer. |
| 5081.
 | 31P MRSI in Pediatric Low Grade Gliomas During Treatment at 7T Philipp Lazen1,2, Karleen T. Oonk3, Iris V. Obdeijn4, Dennis W. J. Klomp3, Sabine L. A. Plasschaert4, Maarten H. Lequin3,4, Giorgo L. Porro5, Gilbert Hangel1,2, Evita C. Wiegers3, and Jannie P. Wijnen3
1Department of Neurosurgery, Medical University of Vienna, Vienna, Austria, 2Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 3Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 4Princess Máxima Center for Pediatric Oncology, Utrecht, Netherlands, 5Department of Ophthalmology, University Medical Center Utrecht, Utrecht, Netherlands Keywords: Non-Proton, Pediatric, Brain tumor, 7T, Neuro, 31P Motivation: Treatment monitoring in pediatric brain tumors is often challenging. Non-invasive tools are needed to
assess tumor activity accurately. Goal(s): To monitor changes in phospholipid metabolism (i.e., phosphomonoesters/phosphodiesters [PME/PDE]) in
pediatric low grade gliomas. Approach: Eleven pediatric brain tumor patients underwent 31P-MRSI at 7T. PME/PDE in the tumor was compared to a
normal-appearing brain voxel. Clinical outcomes were assessed, and results were
compared between treatment and wait-and-scan groups. Results: Tumors selected for treatment showed higher PME/PDE ratios at baseline, hinting at potential
aggressiveness. These ratios decreased during treatment but remained stable in
the wait-and-scan group. Impact: Treatment monitoring in pediatric brain tumors is often challenging. Using 31P-MRSI we
showed that tumors selected for treatment exhibited higher PME/PDE, signifying
potential tumor aggressiveness. PME/PDE levels decreased during treatment,
indicating potential for non-invasive assessment of treatment effects. |
| 5082.
 | Analysis of 31P chemical-shift signatures of high-energy phosphates in glioma patients measured at 7 Tesla Vanessa L. Franke1, Bela Seng 1,2, Justyna Platek1,2,3, Nina Weckesser4, Heinz-Peter Schlemmer4,5, Daniel Paech4,6, Mark E. Ladd1,2,5, Peter Bachert1,2, and Andreas Korzowski1
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany, 3International Max Plank Research School for Quantum Dynamics in Physics, Chemistry, and Biology (IMPRS-QD)), Max Plank for Nucelar Physics (MPIK), Heidelberg, Germany, 4Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 5Faculty of Medicine, Heidelberg University, Heidelberg, Germany, 6Division of Neuroradiology, University Hospital Bonn, Bonn, Germany Keywords: Non-Proton, Spectroscopy, Phosphorus, 31P, pH, magnesium, glioma Motivation: The detailed characterization of tumor micro-environment can be supported by 31P MRSI enabling the non-invasive determination of pH and magnesium ion content (Mg). Goal(s): The aim of this study was to investigate whether a discrimination between different glioma micro-environments might be possible based on the differences in 31P chemical-shift signatures. Approach: For this purpose, 31P MRSI datasets from 12 patients with glioma acquired at 7T were analyzed and used to estimate the underlying pH and Mg values. Results: For the analyzed cohort, different trends in 31P chemical-shift signatures, as well as in pH and Mg values were observed for different tumor subtypes. Impact: The analysis of 31P chemical-shift signatures in glioma patients could potentially be used for stratifying tumor subtypes, and might help in the characterization of tumor microenvironments, e.g. by determining potential biomarkers such as pH and the magnesium ion content. |
| 5083.
 | Robustness of Fitting Frequency-Domain Phased 129Xe Magnetic Resonance Spectra versus Unphased Temporal Domain Free Induction Decays Haoran Dai1 and Bastiaan Driehuys1,2
1Medical Physics Graduate Program, Duke University, Durham, NC, United States, 2Department of Radiology, Duke University, Durham, NC, United States Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Gas) Motivation: Hyperpolarized (HP) 129Xe magnetic resonance (MR) spectroscopy provides useful biomarkers of gas exchange. Some groups analyze phased spectra in the frequency domain, while others employ time-domain fitting. However, these two approaches have never been compared to determine the reliability of the metrics resulting from each approach. Goal(s): This study compares the feasibility, sensitivity, and repeatability of these two methodologies. Approach: 129Xe MRS acquired at 3 Tesla from 242 scans–include 55 repeated measurements of 110 scans–was evaluated using both methods. Results: Time-domain fitting was applicable to all scans, yielded more physiologically plausible chemical shifts and were more repeatable. Impact: Fitting 129Xe spectra acquired at 3 Tesla in the temporal domain outperforms phase correcting and fitting spectra in the frequency domain. |
| 5084.
 | Assessing Cross-Site Variability in 129Xe Spectroscopy Measurements Across Major Scanner Platforms Suphachart Leewiwatwong1, Aryil Bechtel2, David Mummy2, Shuo Zhang2, Junlan Lu3, Zackary Cleveland4, Matthew Willmering4, Juan Parra-Robles4, Sean Fain5, Andrew D Hahn5, and Bastiaan Driehuys1,2,3
1Biomedical Engineering, Duke University, DURHAM, NC, United States, 2Radiology, Duke University, DURHAM, NC, United States, 3Medical Physics Graduate Program, Duke University, DURHAM, NC, United States, 4Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 5Radiology, University of Iowa, Iowa City, IA, United States Keywords: Hyperpolarized MR (Gas), Hyperpolarized MR (Gas) Motivation: Hyperpolarized 129Xe gas exchange magnetic resonance spectroscopy (MRS) lacks standardized healthy reference values. Goal(s): To standardize 129Xe gas exchange MRS biomarker reference values across different MRI systems and estimate a T2* for consistent analysis of 129Xe gas exchange MRI. Approach: Healthy 18-30 yr old non-smokers underwent 129Xe MRS using the consortium recommended protocol across three research centers and three different MRI vendors. Results: Findings indicated consistent RBC-to-membrane ratios across sites but slight differences in RBC shifts, oscillation amplitudes, and T2* values. Impact: Establishing healthy
reference values for multi-site 129Xe spectroscopy will facilitate
its incorporation into collaborative respiratory research. |