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Somai V, Kreis F, Gaunt A, Tsyben A, Chia ML, Hesse F, Wright AJ, Brindle KM. Genetic algorithm-based optimization of pulse sequences. Magn Reson Med 2022; 87:2130-2144. [PMID: 34866238 DOI: 10.1002/mrm.29110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/08/2021] [Accepted: 11/15/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE The performance of pulse sequences in vivo can be limited by fast relaxation rates, magnetic field inhomogeneity, and nonuniform spin excitation. We describe here a method for pulse sequence optimization that uses a stochastic numerical solver that in principle is capable of finding a global optimum. The method provides a simple framework for incorporating any constraint and implementing arbitrarily complex cost functions. Efficient methods for simulating spin dynamics and incorporating frequency selectivity are also described. METHODS Optimized pulse sequences for polarization transfer between protons and X-nuclei and excitation pulses that eliminate J-coupling modulation were evaluated experimentally using a surface coil on phantoms, and also the detection of hyperpolarized [2-13 C]lactate in vivo in the case of J-coupling modulation-free excitation. RESULTS The optimized polarization transfer pulses improved the SNR by ~50% with a more than twofold reduction in the B1 field, and J-coupling modulation-free excitation was achieved with a more than threefold reduction in pulse length. CONCLUSION This process could be used to optimize any pulse when there is a need to improve the uniformity and frequency selectivity of excitation as well as to design new pulses to steer the spin system to any desired achievable state.
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Affiliation(s)
- Vencel Somai
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
- Department of Radiology, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Felix Kreis
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Adam Gaunt
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
| | - Anastasia Tsyben
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
| | - Ming Li Chia
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
| | - Friederike Hesse
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
| | - Alan J Wright
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
| | - Kevin M Brindle
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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Kreis F, Wright AJ, Somai V, Katz‐Brull R, Brindle KM. Increasing the sensitivity of hyperpolarized [ 15 N 2 ]urea detection by serial transfer of polarization to spin-coupled protons. Magn Reson Med 2020; 84:1844-1856. [PMID: 32153046 PMCID: PMC8629126 DOI: 10.1002/mrm.28241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE Hyperpolarized 15 N-labeled molecules have been proposed as imaging agents for investigating tissue perfusion and pH. However, the sensitivity of direct 15 N detection is limited by the isotope's low gyromagnetic ratio. Sensitivity can be increased by transferring 15 N hyperpolarization to spin-coupled protons provided that there is not significant polarization loss during transfer. However, complete polarization transfer would limit the temporal window for imaging to the order of the proton T1 (2-3 s). To exploit the long T1 offered by storing polarization in 15 N and the higher sensitivity of 1 H detection, we have developed a pulse sequence for partial polarization transfer. METHODS A polarization transfer pulse sequence was modified to allow partial polarization transfer, as is required for dynamic measurements, and that can be implemented with inhomogeneous B1 fields, as is often the case in vivo. The sequence was demonstrated with dynamic spectroscopy and imaging measurements with [15 N2 ]urea. RESULTS When compared to direct 15 N detection, the sequence increased the signal-to-noise ratio (SNR) by a factor of 1.72 ± 0.25, where both experiments depleted ~20% of the hyperpolarization (>10-fold when 100% of the hyperpolarization is used). Simulations with measured cross relaxation rates showed that this sequence gave up to a 50-fold increase in urea proton polarization when compared to spontaneous polarization transfer via cross relaxation. CONCLUSION The sequence gave an SNR increase that was close to the theoretical limit and can give a significant SNR benefit when compared to direct 13 C detection of hyperpolarized [13 C]urea.
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Affiliation(s)
- Felix Kreis
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
| | - Alan J. Wright
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
| | - Vencel Somai
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
| | - Rachel Katz‐Brull
- Department of RadiologyFaculty of MedicineHadassah Medical CenterHebrew University of JerusalemJerusalemIsrael
| | - Kevin M. Brindle
- Cancer Research UK Cambridge InstituteUniversity of CambridgeCambridgeUK
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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3
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Topping GJ, Hundshammer C, Nagel L, Grashei M, Aigner M, Skinner JG, Schulte RF, Schilling F. Acquisition strategies for spatially resolved magnetic resonance detection of hyperpolarized nuclei. MAGMA (NEW YORK, N.Y.) 2020; 33:221-256. [PMID: 31811491 PMCID: PMC7109201 DOI: 10.1007/s10334-019-00807-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 12/13/2022]
Abstract
Hyperpolarization is an emerging method in magnetic resonance imaging that allows nuclear spin polarization of gases or liquids to be temporarily enhanced by up to five or six orders of magnitude at clinically relevant field strengths and administered at high concentration to a subject at the time of measurement. This transient gain in signal has enabled the non-invasive detection and imaging of gas ventilation and diffusion in the lungs, perfusion in blood vessels and tissues, and metabolic conversion in cells, animals, and patients. The rapid development of this method is based on advances in polarizer technology, the availability of suitable probe isotopes and molecules, improved MRI hardware and pulse sequence development. Acquisition strategies for hyperpolarized nuclei are not yet standardized and are set up individually at most sites depending on the specific requirements of the probe, the object of interest, and the MRI hardware. This review provides a detailed introduction to spatially resolved detection of hyperpolarized nuclei and summarizes novel and previously established acquisition strategies for different key areas of application.
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Affiliation(s)
- Geoffrey J Topping
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christian Hundshammer
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Luca Nagel
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Martin Grashei
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maximilian Aigner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jason G Skinner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | | | - Franz Schilling
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
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Lacroix R, Rozeman EA, Kreutz M, Renner K, Blank CU. Targeting tumor-associated acidity in cancer immunotherapy. Cancer Immunol Immunother 2018; 67:1331-1348. [PMID: 29974196 PMCID: PMC11028141 DOI: 10.1007/s00262-018-2195-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/29/2018] [Indexed: 12/21/2022]
Abstract
Checkpoint inhibitors, such as cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and programmed cell death-1 (PD-1) monoclonal antibodies have changed profoundly the treatment of melanoma, renal cell carcinoma, non-small cell lung cancer, Hodgkin lymphoma, and bladder cancer. Currently, they are tested in various tumor entities as monotherapy or in combination with chemotherapies or targeted therapies. However, only a subgroup of patients benefit from checkpoint blockade (combinations). This raises the question, which all mechanisms inhibit T cell function in the tumor environment, restricting the efficacy of these immunotherapeutic approaches. Serum activity of lactate dehydrogenase, likely reflecting the glycolytic activity of the tumor cells and thus acidity within the tumor microenvironment, turned out to be one of the strongest markers predicting response to checkpoint inhibition. In this review, we discuss the impact of tumor-associated acidity on the efficacy of T cell-mediated cancer immunotherapy and possible approaches to break this barrier.
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Affiliation(s)
- Ruben Lacroix
- Department of Molecular Oncology and Immunology, Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Elisa A Rozeman
- Department of Medical Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Marina Kreutz
- Department of Internal Medicine III, University Hospital Regensburg, Regensburg, Germany
| | - Kathrin Renner
- Department of Internal Medicine III, University Hospital Regensburg, Regensburg, Germany
| | - Christian U Blank
- Department of Molecular Oncology and Immunology, Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
- Department of Medical Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
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McCormick J, Korchak S, Mamone S, Ertas YN, Liu Z, Verlinsky L, Wagner S, Glöggler S, Bouchard LS. More Than 12 % Polarization and 20 Minute Lifetime of 15 N in a Choline Derivative Utilizing Parahydrogen and a Rhodium Nanocatalyst in Water. Angew Chem Int Ed Engl 2018; 57:10692-10696. [PMID: 29923285 DOI: 10.1002/anie.201804185] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/14/2018] [Indexed: 11/05/2022]
Abstract
Hyperpolarization techniques are key to extending the capabilities of MRI for the investigation of structural, functional and metabolic processes in vivo. Recent heterogeneous catalyst development has produced high polarization in water using parahydrogen with biologically relevant contrast agents. A heterogeneous ligand-stabilized Rh catalyst is introduced that is capable of achieving 15 N polarization of 12.2±2.7 % by hydrogenation of neurine into a choline derivative. This is the highest 15 N polarization of any parahydrogen method in water to date. Notably, this was performed using a deuterated quaternary amine with an exceptionally long spin-lattice relaxation time (T1 ) of 21.0±0.4 min. These results open the door to the possibility of 15 N in vivo imaging using nontoxic similar model systems because of the biocompatibility of the production media and the stability of the heterogeneous catalyst using parahydrogen-induced polarization (PHIP) as the hyperpolarization method.
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Affiliation(s)
- Jeffrey McCormick
- Department of Chemistry and Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA, 90095-1569, USA
| | - Sergey Korchak
- Research Group for NMR Signal Enhancement, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Str. 3A, 37075, Göttingen, Germany
| | - Salvatore Mamone
- Research Group for NMR Signal Enhancement, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Str. 3A, 37075, Göttingen, Germany
| | - Yavuz N Ertas
- Department of Chemistry and Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA, 90095-1569, USA.,Department of Bioengineering, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA, 90095-1569, USA
| | - Zhiyu Liu
- Department of Chemistry and Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA, 90095-1569, USA
| | - Luke Verlinsky
- Department of Chemistry and Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA, 90095-1569, USA
| | - Shawn Wagner
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Davis Building G149E, Los Angeles, CA, 90048, USA
| | - Stefan Glöggler
- Research Group for NMR Signal Enhancement, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Von-Siebold-Str. 3A, 37075, Göttingen, Germany
| | - Louis-S Bouchard
- Department of Chemistry and Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA, 90095-1569, USA.,Department of Bioengineering, University of California at Los Angeles, 607 Charles E Young Drive East, Los Angeles, CA, 90095-1569, USA.,The Molecular Biology Institute, Jonsson Comprehensive Cancer Center, California NanoSystems Institute, University of California at Los Angeles, USA
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McCormick J, Korchak S, Mamone S, Ertas YN, Liu Z, Verlinsky L, Wagner S, Glöggler S, Bouchard L. More Than 12 % Polarization and 20 Minute Lifetime of
15
N in a Choline Derivative Utilizing Parahydrogen and a Rhodium Nanocatalyst in Water. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804185] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Jeffrey McCormick
- Department of Chemistry and Biochemistry University of California at Los Angeles 607 Charles E Young Drive East Los Angeles CA 90095-1569 USA
| | - Sergey Korchak
- Research Group for NMR Signal Enhancement Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration Von-Siebold-Str. 3A 37075 Göttingen Germany
| | - Salvatore Mamone
- Research Group for NMR Signal Enhancement Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration Von-Siebold-Str. 3A 37075 Göttingen Germany
| | - Yavuz N. Ertas
- Department of Chemistry and Biochemistry University of California at Los Angeles 607 Charles E Young Drive East Los Angeles CA 90095-1569 USA
- Department of Bioengineering University of California at Los Angeles 607 Charles E Young Drive East Los Angeles CA 90095-1569 USA
| | - Zhiyu Liu
- Department of Chemistry and Biochemistry University of California at Los Angeles 607 Charles E Young Drive East Los Angeles CA 90095-1569 USA
| | - Luke Verlinsky
- Department of Chemistry and Biochemistry University of California at Los Angeles 607 Charles E Young Drive East Los Angeles CA 90095-1569 USA
| | - Shawn Wagner
- Biomedical Imaging Research Institute Cedars-Sinai Medical Center 8700 Beverly Blvd, Davis Building G149E Los Angeles CA 90048 USA
| | - Stefan Glöggler
- Research Group for NMR Signal Enhancement Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration Von-Siebold-Str. 3A 37075 Göttingen Germany
| | - Louis‐S. Bouchard
- Department of Chemistry and Biochemistry University of California at Los Angeles 607 Charles E Young Drive East Los Angeles CA 90095-1569 USA
- Department of Bioengineering University of California at Los Angeles 607 Charles E Young Drive East Los Angeles CA 90095-1569 USA
- The Molecular Biology Institute Jonsson Comprehensive Cancer Center California NanoSystems Institute University of California at Los Angeles USA
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