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Garrison WJ, Qing K, Tafti S, Mugler JP, Shim YM, Mata JF, Cates GD, de Lange EE, Meyer CH, Cai J, Miller GW. Highly accelerated dynamic acquisition of 3D grid-tagged hyperpolarized-gas lung images using compressed sensing. Magn Reson Med 2023; 89:2255-2263. [PMID: 36669874 PMCID: PMC10760126 DOI: 10.1002/mrm.29595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/22/2023]
Abstract
PURPOSE To develop and test compressed sensing-based multiframe 3D MRI of grid-tagged hyperpolarized gas in the lung. THEORY AND METHODS Applying grid-tagging RF pulses to inhaled hyperpolarized gas results in images in which signal intensity is predictably and sparsely distributed. In the present work, this phenomenon was used to produce a sampling pattern in which k-space is undersampled by a factor of approximately seven, yet regions of high k-space energy remain densely sampled. Three healthy subjects received multiframe 3D 3 He tagging MRI using this undersampling method. Images were collected during a single exhalation at eight timepoints spanning the breathing cycle from end-of-inhalation to end-of-exhalation. Grid-tagged images were used to generate 3D displacement maps of the lung during exhalation, and time-resolved maps of principal strains and fractional volume change were generated from these displacement maps using finite-element analysis. RESULTS Tags remained clearly resolvable for 4-6 timepoints (5-8 s) in each subject. Displacement maps revealed noteworthy temporal and spatial nonlinearities in lung motion during exhalation. Compressive normal strains occurred along all three principal directions but were primarily oriented in the head-foot direction. Fractional volume changes displayed clear bilateral symmetry, but with the lower lobes displaying slightly higher change than the upper lobes in 2 of the 3 subjects. CONCLUSION We developed a compressed sensing-based method for multiframe 3D MRI of grid-tagged hyperpolarized gas in the lung during exhalation. This method successfully overcomes previous challenges for 3D dynamic grid-tagging, allowing time-resolved biomechanical readouts of lung function to be generated.
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Affiliation(s)
- William J. Garrison
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Kun Qing
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA
| | - Sina Tafti
- Department of Physics, University of Virginia, Charlottesville, VA
| | - John P. Mugler
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA
| | - Y. Michael Shim
- Department of Medicine, University of Virginia, Charlottesville, VA
| | - Jaime F. Mata
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA
| | - Gordon D. Cates
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA
- Department of Physics, University of Virginia, Charlottesville, VA
| | - Eduard E. de Lange
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA
| | - Craig H. Meyer
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA
| | - Jing Cai
- Department of Health Technology and Informatics, Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - G. Wilson Miller
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA
- Department of Physics, University of Virginia, Charlottesville, VA
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Hsieh A, Assadinia N, Hackett TL. Airway remodeling heterogeneity in asthma and its relationship to disease outcomes. Front Physiol 2023; 14:1113100. [PMID: 36744026 PMCID: PMC9892557 DOI: 10.3389/fphys.2023.1113100] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
Asthma affects an estimated 262 million people worldwide and caused over 461,000 deaths in 2019. The disease is characterized by chronic airway inflammation, reversible bronchoconstriction, and airway remodeling. Longitudinal studies have shown that current treatments for asthma (inhaled bronchodilators and corticosteroids) can reduce the frequency of exacerbations, but do not modify disease outcomes over time. Further, longitudinal studies in children to adulthood have shown that these treatments do not improve asthma severity or fixed airflow obstruction over time. In asthma, fixed airflow obstruction is caused by remodeling of the airway wall, but such airway remodeling also significantly contributes to airway closure during bronchoconstriction in acute asthmatic episodes. The goal of the current review is to understand what is known about the heterogeneity of airway remodeling in asthma and how this contributes to the disease process. We provide an overview of the existing knowledge on airway remodeling features observed in asthma, including loss of epithelial integrity, mucous cell metaplasia, extracellular matrix remodeling in both the airways and vessels, angiogenesis, and increased smooth muscle mass. While such studies have provided extensive knowledge on different aspects of airway remodeling, they have relied on biopsy sampling or pathological assessment of lungs from fatal asthma patients, which have limitations for understanding airway heterogeneity and the entire asthma syndrome. To further understand the heterogeneity of airway remodeling in asthma, we highlight the potential of in vivo imaging tools such as computed tomography and magnetic resonance imaging. Such volumetric imaging tools provide the opportunity to assess the heterogeneity of airway remodeling within the whole lung and have led to the novel identification of heterogenous gas trapping and mucus plugging as important predictors of patient outcomes. Lastly, we summarize the current knowledge of modification of airway remodeling with available asthma therapeutics to highlight the need for future studies that use in vivo imaging tools to assess airway remodeling outcomes.
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Affiliation(s)
- Aileen Hsieh
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Najmeh Assadinia
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Tillie-Louise Hackett
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada,*Correspondence: Tillie-Louise Hackett,
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Subasinghe SAAS, Pautler RG, Samee MAH, Yustein JT, Allen MJ. Dual-Mode Tumor Imaging Using Probes That Are Responsive to Hypoxia-Induced Pathological Conditions. BIOSENSORS 2022; 12:478. [PMID: 35884281 PMCID: PMC9313010 DOI: 10.3390/bios12070478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/22/2022] [Accepted: 06/26/2022] [Indexed: 05/02/2023]
Abstract
Hypoxia in solid tumors is associated with poor prognosis, increased aggressiveness, and strong resistance to therapeutics, making accurate monitoring of hypoxia important. Several imaging modalities have been used to study hypoxia, but each modality has inherent limitations. The use of a second modality can compensate for the limitations and validate the results of any single imaging modality. In this review, we describe dual-mode imaging systems for the detection of hypoxia that have been reported since the start of the 21st century. First, we provide a brief overview of the hallmarks of hypoxia used for imaging and the imaging modalities used to detect hypoxia, including optical imaging, ultrasound imaging, photoacoustic imaging, single-photon emission tomography, X-ray computed tomography, positron emission tomography, Cerenkov radiation energy transfer imaging, magnetic resonance imaging, electron paramagnetic resonance imaging, magnetic particle imaging, and surface-enhanced Raman spectroscopy, and mass spectrometric imaging. These overviews are followed by examples of hypoxia-relevant imaging using a mixture of probes for complementary single-mode imaging techniques. Then, we describe dual-mode molecular switches that are responsive in multiple imaging modalities to at least one hypoxia-induced pathological change. Finally, we offer future perspectives toward dual-mode imaging of hypoxia and hypoxia-induced pathophysiological changes in tumor microenvironments.
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Affiliation(s)
| | - Robia G. Pautler
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA; (R.G.P.); (M.A.H.S.)
| | - Md. Abul Hassan Samee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA; (R.G.P.); (M.A.H.S.)
| | - Jason T. Yustein
- Integrative Molecular and Biomedical Sciences and the Department of Pediatrics in the Texas Children’s Cancer and Hematology Centers and The Faris D. Virani Ewing Sarcoma Center, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Matthew J. Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA;
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Ohno Y, Seo JB, Parraga G, Lee KS, Gefter WB, Fain SB, Schiebler ML, Hatabu H. Pulmonary Functional Imaging: Part 1-State-of-the-Art Technical and Physiologic Underpinnings. Radiology 2021; 299:508-523. [PMID: 33825513 DOI: 10.1148/radiol.2021203711] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over the past few decades, pulmonary imaging technologies have advanced from chest radiography and nuclear medicine methods to high-spatial-resolution or low-dose chest CT and MRI. It is currently possible to identify and measure pulmonary pathologic changes before these are obvious even to patients or depicted on conventional morphologic images. Here, key technological advances are described, including multiparametric CT image processing methods, inhaled hyperpolarized and fluorinated gas MRI, and four-dimensional free-breathing CT and MRI methods to measure regional ventilation, perfusion, gas exchange, and biomechanics. The basic anatomic and physiologic underpinnings of these pulmonary functional imaging techniques are explained. In addition, advances in image analysis and computational and artificial intelligence (machine learning) methods pertinent to functional lung imaging are discussed. The clinical applications of pulmonary functional imaging, including both the opportunities and challenges for clinical translation and deployment, will be discussed in part 2 of this review. Given the technical advances in these sophisticated imaging methods and the wealth of information they can provide, it is anticipated that pulmonary functional imaging will be increasingly used in the care of patients with lung disease. © RSNA, 2021 Online supplemental material is available for this article.
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Affiliation(s)
- Yoshiharu Ohno
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Joon Beom Seo
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Grace Parraga
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Kyung Soo Lee
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Warren B Gefter
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Sean B Fain
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Mark L Schiebler
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Hiroto Hatabu
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
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Inhaled Gas Magnetic Resonance Imaging: Advances, Applications, Limitations, and New Frontiers. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00013-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Peñate Medina T, Kolb JP, Hüttmann G, Huber R, Peñate Medina O, Ha L, Ulloa P, Larsen N, Ferrari A, Rafecas M, Ellrichmann M, Pravdivtseva MS, Anikeeva M, Humbert J, Both M, Hundt JE, Hövener JB. Imaging Inflammation - From Whole Body Imaging to Cellular Resolution. Front Immunol 2021; 12:692222. [PMID: 34248987 PMCID: PMC8264453 DOI: 10.3389/fimmu.2021.692222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/12/2021] [Indexed: 01/31/2023] Open
Abstract
Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view.
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Affiliation(s)
- Tuula Peñate Medina
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center, Schleswig-Holstein Kiel University, Kiel, Germany
- *Correspondence: Tuula Peñate Medina, ; Jan-Bernd Hövener,
| | - Jan Philip Kolb
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
| | - Gereon Hüttmann
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
- Airway Research Center North (ARCN), Member of the German Center of Lung Research (DZL), Gießen, Germany
| | - Robert Huber
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
| | - Oula Peñate Medina
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center, Schleswig-Holstein Kiel University, Kiel, Germany
- Institute for Experimental Cancer Research (IET), University of Kiel, Kiel, Germany
| | - Linh Ha
- Department of Dermatology, Allergology and Venereology, University Hospital Schleswig-Holstein Lübeck (UKSH), Lübeck, Germany
| | - Patricia Ulloa
- Department of Radiology and Neuroradiology, University Medical Centers Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Naomi Larsen
- Department of Radiology and Neuroradiology, University Medical Centers Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Arianna Ferrari
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center, Schleswig-Holstein Kiel University, Kiel, Germany
| | - Magdalena Rafecas
- Institute of Medical Engineering (IMT), University of Lübeck, Lübeck, Germany
| | - Mark Ellrichmann
- Interdisciplinary Endoscopy, Medical Department1, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Mariya S. Pravdivtseva
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center, Schleswig-Holstein Kiel University, Kiel, Germany
- Department of Radiology and Neuroradiology, University Medical Centers Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Mariia Anikeeva
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center, Schleswig-Holstein Kiel University, Kiel, Germany
| | - Jana Humbert
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center, Schleswig-Holstein Kiel University, Kiel, Germany
- Department of Radiology and Neuroradiology, University Medical Centers Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Marcus Both
- Department of Radiology and Neuroradiology, University Medical Centers Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Jennifer E. Hundt
- Lübeck Institute for Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Jan-Bernd Hövener
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center, Schleswig-Holstein Kiel University, Kiel, Germany
- *Correspondence: Tuula Peñate Medina, ; Jan-Bernd Hövener,
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Voskrebenzev A, Vogel-Claussen J. Proton MRI of the Lung: How to Tame Scarce Protons and Fast Signal Decay. J Magn Reson Imaging 2020; 53:1344-1357. [PMID: 32166832 DOI: 10.1002/jmri.27122] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/20/2020] [Accepted: 02/20/2020] [Indexed: 12/19/2022] Open
Abstract
Pulmonary proton MRI techniques offer the unique possibility of assessing lung function and structure without the requirement for hyperpolarization or dedicated hardware, which is mandatory for multinuclear acquisition. Five popular approaches are presented and discussed in this review: 1) oxygen enhanced (OE)-MRI; 2) arterial spin labeling (ASL); 3) Fourier decomposition (FD) MRI and other related methods including self-gated noncontrast-enhanced functional lung (SENCEFUL) MR and phase-resolved functional lung (PREFUL) imaging; 4) dynamic contrast-enhanced (DCE) MRI; and 5) ultrashort TE (UTE) MRI. While DCE MRI is the most established and well-studied perfusion measurement, FD MRI offers a free-breathing test without any contrast agent and is predestined for application in patients with renal failure or with low compliance. Additionally, FD MRI and related methods like PREFUL and SENCEFUL can act as an ionizing radiation-free V/Q scan, since ventilation and perfusion information is acquired simultaneously during one scan. For OE-MRI, different concentrations of oxygen are applied via a facemask to assess the regional change in T1 , which is caused by the paramagnetic property of oxygen. Since this change is governed by a combination of ventilation, diffusion, and perfusion, a compound functional measurement can be achieved with OE-MRI. The known problem of fast T2 * decay of the lung parenchyma leading to a low signal-to-noise ratio is bypassed by the UTE acquisition strategy. Computed tomography (CT)-like images allow the assessment of lung structure with high spatial resolution without ionizing radiation. Despite these different branches of proton MRI, common trends are evident among pulmonary proton MRI: 1) free-breathing acquisition with self-gating; 2) application of UTE to preserve a stronger parenchymal signal; and 3) transition from 2D to 3D acquisition. On that note, there is a visible convergence of the different methods and it is not difficult to imagine that future methods will combine different aspects of the presented methods.
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Affiliation(s)
- Andreas Voskrebenzev
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Member of the German Lung Research Center (DZL), Hannover, Germany
| | - Jens Vogel-Claussen
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Member of the German Lung Research Center (DZL), Hannover, Germany
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Klimeš F, Voskrebenzev A, Gutberlet M, Kern A, Behrendt L, Kaireit TF, Czerner C, Renne J, Wacker F, Vogel-Claussen J. Free-breathing quantification of regional ventilation derived by phase-resolved functional lung (PREFUL) MRI. NMR IN BIOMEDICINE 2019; 32:e4088. [PMID: 30908743 DOI: 10.1002/nbm.4088] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/11/2019] [Accepted: 02/12/2019] [Indexed: 06/09/2023]
Abstract
PURPOSE To test the feasibility of regional fully quantitative ventilation measurement in free breathing derived by phase-resolved functional lung (PREFUL) MRI in the supine and prone positions. In addition, the influence of T2 * relaxation time on ventilation quantification is assessed. METHODS Twelve healthy volunteers underwent functional MRI at 1.5 T using a 2D triple-echo spoiled gradient echo sequence allowing for quantitative measurement of T2 * relaxation time. Minute ventilation (ΔV) was quantified by conventional fractional ventilation (FV) and the newly introduced regional ventilation (VR), which corrects volume errors due to image registration. ΔVFV versus ΔVVR and ΔVVR versus ΔVVR with T2 * correction were compared using Bland-Altman plots and correlation analysis. The repeatability and physiological plausibility of all measurements were tested in the supine and prone positions. RESULTS On global and regional scales a strong correlation was observed between ΔVFV versus ΔVVR and ΔVVR versus ΔVVRT2* (r > 0.93); however, regional Bland-Altman analysis showed systematic differences (p < 0.0001). Unlike ΔVVRT2* , ΔVVR and ΔVFV showed expected physiologic anterior-posterior gradients, which decreased in the supine but not in the prone position at second measurement during 3 min in the same position. For all quantification methods a moderate repeatability (coefficient of variation <20%) of ventilation was found. CONCLUSION A fully quantified regional ventilation measurement using ΔVVR in free breathing is feasible and shows physiologically plausible results. In contrast to conventional ΔVFV, volume errors due to image registration are eliminated with the ΔVVR approach. However, correction for the T2 * effect remains challenging.
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Affiliation(s)
- F Klimeš
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - A Voskrebenzev
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - M Gutberlet
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - A Kern
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - L Behrendt
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - T F Kaireit
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - C Czerner
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - J Renne
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - F Wacker
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - J Vogel-Claussen
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
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Ladd ME, Bachert P, Meyerspeer M, Moser E, Nagel AM, Norris DG, Schmitter S, Speck O, Straub S, Zaiss M. Pros and cons of ultra-high-field MRI/MRS for human application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:1-50. [PMID: 30527132 DOI: 10.1016/j.pnmrs.2018.06.001] [Citation(s) in RCA: 275] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI. In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioural Brain Sciences, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Sina Straub
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz Zaiss
- High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany.
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Kern AL, Vogel-Claussen J. Hyperpolarized gas MRI in pulmonology. Br J Radiol 2018; 91:20170647. [PMID: 29271239 PMCID: PMC5965996 DOI: 10.1259/bjr.20170647] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/12/2017] [Accepted: 12/08/2017] [Indexed: 01/20/2023] Open
Abstract
Lung diseases have a high prevalence amongst the world population and their early diagnosis has been pointed out to be key for successful treatment. However, there is still a lack of non-invasive examination methods with sensitivity to early, local deterioration of lung function. Proton-based lung MRI is particularly challenging due to short T2* times and low proton density within the lung tissue. Hyperpolarized gas MRI is aan emerging technology providing a richness of methodologies which overcome the aforementioned problems. Unlike proton-based MRI, lung MRI of hyperpolarized gases may rely on imaging of spins in the lung's gas spaces or inside the lung tissue and thereby add substantial value and diagnostic potential to lung MRI. This review article gives an introduction to the MR physics of hyperpolarized media and presents the current state of hyperpolarized gas MRI of 3Headvasd and 129Xe in pulmonology. Key applications, ranging from static and dynamic ventilation imaging as well as oxygen-pressure mapping to 129Xe dissolved-phase imaging and spectroscopy are presented. Hyperpolarized gas MRI is compared to alternative examination methods based on MRI and future directions of hyperpolarized gas MRI are discussed.
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Chahal S, Prete BRJ, Wade A, Hane FT, Albert MS. Brain Imaging Using Hyperpolarized 129Xe Magnetic Resonance Imaging. Methods Enzymol 2018; 603:305-320. [PMID: 29673533 DOI: 10.1016/bs.mie.2018.01.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Hyperpolarized (HP) 129Xe magnetic resonance imaging (MRI) is a novel iteration of traditional MRI that relies on detecting the spins of 1H. Since 129Xe is a gaseous signal source, it can be used for lung imaging. Additionally, 129Xe dissolves in the blood stream and can therefore be detectable in the brain parenchyma and vasculature. In this work, we provide detailed information on the protocols that we have developed to image 129Xe within the brains of both rodents and human subjects.
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Affiliation(s)
| | | | - Alanna Wade
- Lakehead University, Thunder Bay, ON, Canada
| | - Francis T Hane
- Lakehead University, Thunder Bay, ON, Canada; Thunder Bay Regional Health Research Institute, Thunder Bay, ON, Canada.
| | - Mitchell S Albert
- Lakehead University, Thunder Bay, ON, Canada; Thunder Bay Regional Health Research Institute, Thunder Bay, ON, Canada; Northern Ontario School of Medicine, Thunder Bay, ON, Canada
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12
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13
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MR-Bildkontrast durch chemischen Austausch. Z Med Phys 2016; 26:1-2. [DOI: 10.1016/j.zemedi.2015.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Ruppert K, Altes TA, Mata JF, Ruset IC, Hersman FW, Mugler JP. Detecting pulmonary capillary blood pulsations using hyperpolarized xenon-129 chemical shift saturation recovery (CSSR) MR spectroscopy. Magn Reson Med 2015; 75:1771-80. [PMID: 26017009 DOI: 10.1002/mrm.25794] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/06/2015] [Accepted: 05/05/2015] [Indexed: 01/11/2023]
Abstract
PURPOSE To investigate whether chemical shift saturation recovery (CSSR) MR spectroscopy with hyperpolarized xenon-129 is sensitive to the pulsatile nature of pulmonary blood flow during the cardiac cycle. METHODS A CSSR pulse sequence typically uses radiofrequency (RF) pulses to saturate the magnetization of xenon-129 dissolved in lung tissue followed, after a variable delay time, by an RF excitation and subsequent acquisition of a free-induction decay. Thereby it is possible to monitor the uptake of xenon-129 by lung tissue and extract physiological parameters of pulmonary gas exchange. In the current studies, the delay time was instead held at a constant value, which permitted observation of xenon-129 gas uptake as a function of breath-hold time. CSSR studies were performed in 13 subjects (10 healthy, 2 chronic obstructive pulmonary disease [COPD], 1 second-hand smoke exposure), holding their breath at total lung capacity. RESULTS The areas of the tissue/plasma and the red-blood-cell peaks in healthy subjects varied by an average of 1.7±0.7% and 15.1±3.8%, respectively, during the cardiac cycle. In 2 subjects with COPD these peak pulsations were not detectable during at least part of the measurement period. CONCLUSION CSSR spectroscopy is sufficiently sensitive to detect oscillations in the xenon-129 gas-uptake rate associated with the cardiac cycle.
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Affiliation(s)
- Kai Ruppert
- Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA.,Department of Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio, USA
| | - Talissa A Altes
- Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA
| | - Jaime F Mata
- Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA
| | - Iulian C Ruset
- Xemed, LLC, Durham, New Hampshire, USA.,Department of Physics, University of New Hampshire, Durham, New Hampshire, USA
| | - F William Hersman
- Xemed, LLC, Durham, New Hampshire, USA.,Department of Physics, University of New Hampshire, Durham, New Hampshire, USA
| | - John P Mugler
- Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA
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15
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Sarracanie M, Grebenkov D, Sandeau J, Coulibaly S, Martin AR, Hill K, Pérez Sánchez JM, Fodil R, Martin L, Durand E, Caillibotte G, Isabey D, Darrasse L, Bittoun J, Maître X. Phase-contrast helium-3 MRI of aerosol deposition in human airways. NMR IN BIOMEDICINE 2015; 28:180-187. [PMID: 25476994 DOI: 10.1002/nbm.3238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 09/15/2014] [Accepted: 10/30/2014] [Indexed: 06/04/2023]
Abstract
One of the key challenges in the study of health-related aerosols is predicting and monitoring sites of particle deposition in the respiratory tract. The potential health risks of ambient exposure to environmental or workplace aerosols and the beneficial effects of medical aerosols are strongly influenced by the site of aerosol deposition along the respiratory tract. Nuclear medicine is the only current modality that combines quantification and regional localization of aerosol deposition, and this technique remains limited by its spatial and temporal resolutions and by patient exposure to radiation. Recent work in MRI has shed light on techniques to quantify micro-sized magnetic particles in living bodies by the measurement of associated static magnetic field variations. With regard to lung MRI, hyperpolarized helium-3 may be used as a tracer gas to compensate for the lack of MR signal in the airways, so as to allow assessment of pulmonary function and morphology. The extrathoracic region of the human respiratory system plays a critical role in determining aerosol deposition patterns, as it acts as a filter upstream from the lungs. In the present work, aerosol deposition in a mouth-throat phantom was measured using helium-3 MRI and compared with single-photon emission computed tomography. By providing high sensitivity with high spatial and temporal resolutions, phase-contrast helium-3 MRI offers new insights for the study of particle transport and deposition.
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Affiliation(s)
- Mathieu Sarracanie
- Imagerie par Résonance Magnétique Médicale et Multi-Modalités (UMR8081), IR4M, Université Paris-Sud, CNRS, Orsay, France; Department of Physics, Harvard University, Cambridge, MA, USA; MGH/A. A. Martinos Center for Biomedical Imaging, Boston, MA, USA
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Ruppert K. Biomedical imaging with hyperpolarized noble gases. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:116701. [PMID: 25360484 DOI: 10.1088/0034-4885/77/11/116701] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Hyperpolarized noble gases (HNGs), polarized to approximately 50% or higher, have led to major advances in magnetic resonance (MR) imaging of porous structures and air-filled cavities in human subjects, particularly the lung. By boosting the available signal to a level about 100 000 times higher than that at thermal equilibrium, air spaces that would otherwise appear as signal voids in an MR image can be revealed for structural and functional assessments. This review discusses how HNG MR imaging differs from conventional proton MR imaging, how MR pulse sequence design is affected and how the properties of gas imaging can be exploited to obtain hitherto inaccessible information in humans and animals. Current and possible future imaging techniques, and their application in the assessment of normal lung function as well as certain lung diseases, are described.
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17
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A hyperpolarized equilibrium for magnetic resonance. Nat Commun 2014; 4:2946. [PMID: 24336292 PMCID: PMC3905697 DOI: 10.1038/ncomms3946] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 11/15/2013] [Indexed: 11/09/2022] Open
Abstract
Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all ¹H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10⁻³ Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application.
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18
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Głowacz B, Suchanek M, Olejniczak Z. Production of laser-polarized 3He gas via metastability exchange optical pumping for magnetic resonance imaging. BIO-ALGORITHMS AND MED-SYSTEMS 2014. [DOI: 10.1515/bams-2014-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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19
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Witte C, Schröder L. NMR of hyperpolarised probes. NMR IN BIOMEDICINE 2013; 26:788-802. [PMID: 23033215 DOI: 10.1002/nbm.2873] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 07/23/2012] [Accepted: 08/29/2012] [Indexed: 06/01/2023]
Abstract
Increasing the sensitivity of NMR experiments is an ongoing field of research to help realise the exquisite molecular specificity of this technique. Hyperpolarisation of various nuclei is a powerful approach that enables the use of NMR for molecular and cellular imaging. Substantial progress has been achieved over recent years in terms of both tracer preparation and detection schemes. This review summarises recent developments in probe design and optimised signal encoding, and promising results in sensitive disease detection and efficient therapeutic monitoring. The different methods have great potential to provide molecular specificity not available by other diagnostic modalities.
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Affiliation(s)
- Christopher Witte
- ERC Project BiosensorImaging, Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
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20
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Mulder WJM, McMahon MT, Nicolay K. The evolution of MRI probes: from the initial development to state-of-the-art applications. NMR IN BIOMEDICINE 2013; 26:725-727. [PMID: 23784954 DOI: 10.1002/nbm.2976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 04/20/2013] [Indexed: 06/02/2023]
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Borowiak R, Schwaderlapp N, Huethe F, Lickert T, Fischer E, Bär S, Hennig J, von Elverfeldt D, Hövener JB. A battery-driven, low-field NMR unit for thermally and hyperpolarized samples. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2013; 26:491-9. [PMID: 23412980 DOI: 10.1007/s10334-013-0366-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 12/14/2012] [Accepted: 01/10/2013] [Indexed: 11/29/2022]
Abstract
OBJECT The design of a multinuclear low-field NMR unit with variable field strength <6 mT providing accurate spin manipulations and sufficient sensitivity for direct detection of samples in thermal equilibrium to aid parahydrogen-based hyperpolarization experiments. MATERIALS AND METHODS An optimized, resistive magnet connected to a battery or wall-power driven current source was constructed to provide a magnetic field <6 mT. A digital device connected to a saddle-shaped transmit- and solenoid receive-coil enabled MR signal excitation and detection with up to 10(6) samples/s, controlled by a flexible pulse-programming software. RESULTS The magnetization of thermally polarized samples at 1.8 and 5.7 mT is detected in a single acquisition with a SNR ≈10(1) and ≈10(2) and a line width of 42 and 32 Hz, respectively. Nuclear spins are manipulated to an uncertainty of ±1° by means of pulses, which can be arranged in an arbitrary combination. As a demonstration, standard experiments for the measurement of relaxation parameters of thermally polarized samples were implemented. The detection of much stronger hyperpolarized signal was exemplified employing parahydrogen. CONCLUSION Direct detection of thermal and hyperpolarized (1)H-MR signal in a single acquisition and accurate spin manipulations at 1.8 and 5.5 mT were successfully demonstrated.
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Affiliation(s)
- Robert Borowiak
- Medical Physics, Department of Radiology, University Medical Center Freiburg, Breisacher Straße 60A, 79106, Freiburg, Germany
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Risse F, Pesic J, Young S, Olsson LE. A texture analysis approach to quantify ventilation changes in hyperpolarised ³He MRI of the rat lung in an asthma model. NMR IN BIOMEDICINE 2012; 25:131-141. [PMID: 21739495 DOI: 10.1002/nbm.1725] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 03/17/2011] [Accepted: 03/17/2011] [Indexed: 05/31/2023]
Abstract
In preclinical research, allergic asthma is investigated in rats sensitised with the antigen ovalbumin (OVA), followed by a challenge with aerosolised OVA to induce an inflammatory reaction of the lower airways. This causes diffuse, nonfocal ventilation defects that lead to heterogeneously distributed signal intensities in hyperpolarised (HP) (3)He MR images, which are difficult to assess directly by diagnostic grading or volumetry. Texture analysis can characterise these changes and does not require segmentation of the lung structures prior to the analysis. The aim of this work was to evaluate a texture analysis approach to quantify changes in lung ventilation in HP (3)He MRI of OVA-challenged rats. OVA-challenged animals were treated with two different compound doses to evaluate the sensitivity of the texture analysis. Four groups were investigated using HP (3)He MRI at 4.7 T: controls, vehicle-treated, and low- and high-dose budesonide-treated rats. In addition, broncho-alveolar lavage was performed and the eosinophil cell count was used as a biological reference marker. First-order texture, geometrical features and features based on second-order statistics using run-length and grey-level co-occurrence matrices were calculated. In addition, wavelet transforms were applied to compute first-order statistics on multiple scales. The texture analysis was able to show significant differences between the control and untreated vehicle groups as well as between the vehicle and treatment groups. This is in agreement with the findings of the eosinophil cell counts, which were used as a marker for the severity of inflammation. However, not all features used in the different texture analysis methods could differentiate between the treatment groups. In conclusion, texture analysis can be used to quantify changes in lung ventilation as measured with HP (3)He MRI after therapeutic intervention with budesonide.
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Affiliation(s)
- Frank Risse
- DECS Imaging&Antibodies, AstraZeneca R&D, Mölndal, Sweden.
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Deppe MH, Parra-Robles J, Ajraoui S, Wild JM. Combined measurement of pulmonary inert gas washout and regional ventilation heterogeneity by MR of a single dose of hyperpolarized 3
He. Magn Reson Med 2010; 65:1075-83. [DOI: 10.1002/mrm.22709] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 09/08/2010] [Accepted: 10/08/2010] [Indexed: 11/11/2022]
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Abstract
Hyperpolarized gas magnetic resonance imaging has been explored extensively as a promising tool for the quantitative evaluation of regional pulmonary pathophysiology. This noninvasive technique is capable of providing both structural information down to the level of the alveolar microstructure and functional information, such as dynamic ventilation, intrapulmonary partial pressure of oxygen, and alveolar surface area. This study reviews the role of hyperpolarized 3-helium and 129-xenon magnetic resonance imaging in this research.
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25
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Salito C, Aliverti A, Gierada DS, Deslée G, Pierce RA, Macklem PT, Woods JC. Quantification of trapped gas with CT and 3 He MR imaging in a porcine model of isolated airway obstruction. Radiology 2009; 253:380-9. [PMID: 19703847 DOI: 10.1148/radiol.2532081941] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To quantify regional gas trapping in the lung by using computed tomographic (CT)-determined specific gas volume and hyperpolarized helium 3 ((3)He) magnetic resonance (MR) imaging in a porcine model of airway obstruction. MATERIALS AND METHODS Four porcine lungs were removed after sacrifice for unrelated cardiac experiments, for which animal studies approval was obtained. Dynamic expiratory thin-section CT and (3)He MR imaging were performed during passive deflation from total lung capacity after obstructions were created with inverted one-way endobronchial exit valves in segmental or lobar bronchi to produce identifiable regions of trapped gas. Changes in specific gas volume were assessed from CT data for defined regions of interest within and outside of obstructed segments and for entire lobes. Helium 3 data were analyzed according to the corresponding regional signal reduction during expiration, compared with the total magnetic moment at each time point. RESULTS In 4.5 seconds of free collapse, volume decreased by 6% +/- 2 (standard error) and 53% +/- 3, respectively, in trapped-gas lobes and in unobstructed regions (P < .0001). Specific gas volume changed by 6% +/- 2 in areas of trapped gas and decreased by 56% +/- 3 in unobstructed regions, from 3.4 mL/g +/- 0.2 to 1.5 mL/g +/- 0.1 (P < .0001). The (3)He signal intensity decreased by 25% +/- 6 and 71% +/- 3, respectively, in trapped-gas and normal regions (P = .0008). In unobstructed regions, the percentage decreases in specific gas volume and (3)He signal intensity were not statistically different from one another (P = .89). CONCLUSION The results obtained from the model of gas trapping demonstrate that CT-determined specific gas volume and (3)He MR imaging can help identify and quantify the extent of regional trapped gas in explanted porcine lungs.
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Affiliation(s)
- Caterina Salito
- Department of Bioengineering, Politecnico di Milano, Milan, Italy
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Yu J, Law M, Kadlecek S, Emami K, Ishii M, Stephen M, Woodburn JM, Vahdat V, Rizi RR. Simultaneous measurement of pulmonary partial pressure of oxygen and apparent diffusion coefficient by hyperpolarized 3He MRI. Magn Reson Med 2009; 61:1015-21. [PMID: 19230017 DOI: 10.1002/mrm.21854] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hyperpolarized (3)He (HP (3)He) MRI shows promise to assess structural and functional pulmonary parameters in a sensitive, regional, and noninvasive way. Structural HP (3)He MRI has applied the apparent diffusion coefficient (ADC) for the detection of disease-induced lung microstructure changes at the alveolar level, and HP (3)He pulmonary partial pressure of oxygen (pO(2)) imaging measures the oxygen transfer efficiency between the lung and blood stream. Although both parameters are affected in chronic obstructive pulmonary disease (COPD), a quantitative assessment of the regional correlation of the two parameters has not been reported in the literature. In this work, a single acquisition technique for the simultaneous measurement of ADC and pO(2) is presented. This technique is based on the multiple regression method, in which a general linear estimator is used to retrieve the values of ADC and pO(2) from a series of measurements. The measurement uncertainties are also analytically derived and used to find an optimal measurement scheme. The technique was first tested on a phantom model, and then on an in vivo normal pig experiment. A case study was performed on a COPD patient, which showed that in a region of interest ADC was 29% higher while oxygen depletion rate was 61% lower than the corresponding global average values.
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Affiliation(s)
- Jiangsheng Yu
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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27
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Yu J, Rajaei S, Ishii M, Law M, Emami K, Woodburn JM, Kadlecek S, Vahdat V, Rizi RR. Measurement of pulmonary partial pressure of oxygen and oxygen depletion rate with hyperpolarized helium-3 MRI: a preliminary reproducibility study on pig model. Acad Radiol 2008; 15:702-12. [PMID: 18486007 DOI: 10.1016/j.acra.2008.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2007] [Revised: 01/18/2008] [Accepted: 01/19/2008] [Indexed: 10/22/2022]
Abstract
RATIONAL AND OBJECTIVES Pulmonary partial pressure of oxygen (pO(2)) and oxygen depletion rate (R) are two important parameters of lung function. The dependence of hyperpolarized (3)He (HP (3)He) T(1) on local oxygen concentration provides the basis for high-resolution mapping of the regional distributions of pO(2) and R in the lung. Although the oxygen-sensitive HP (3)He magnetic resonance imaging technique has been applied in human subjects and several animal species, reproducibility studies are rarely reported in the literature. This work presents a preliminary reproducibility study on a pig model. In this study, important scan parameters, such as measurement timing and flip angle, are optimized to minimize the noise-induced measurement uncertainty. MATERIALS AND METHODS In the in vivo study, five normal pigs and one diseased pig with simulated pulmonary emboli were scanned with a small flip angle gradient echo sequence. The pulmonary oxygen measurement was repeated two to four times in each pig. In each measurement, a series of six images were acquired with optimal timing and flip angle. The parametric maps were generated using a bin-based data processing procedure that applied the multiple regression fitting method to extract the pO(2) and R. Variations of global mean, percentiles, and regions of interest were calculated from the maps to analyze reproducibility. RESULTS The global statistical analyses show that average variation of global mean is 10.7% for pO(2) and 23.8% for R, and that the average variation of percentiles (10th, 25th, 50th, 75th, and 90th) and interquartile range is 14.8% for pO(2) and 30.4% for R. The region-of-interest analysis on the manually selected regions shows that the average variation of mean is 12.6% for pO(2) and 21.9% for R. CONCLUSION In this work, a preliminary study on the reproducibility of measuring pO(2) and R with HP (3)He magnetic resonance imaging on a pig model is presented.
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Yu J, Ishii M, Law M, Woodburn JM, Emami K, Kadlecek S, Vahdat V, Guyer RA, Rizi RR. Optimization of scan parameters in pulmonary partial pressure oxygen measurement by hyperpolarized 3He MRI. Magn Reson Med 2008; 59:124-31. [PMID: 18050348 DOI: 10.1002/mrm.21416] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The dependence of hyperpolarized (HP) (3)He T(1) on local oxygen concentration provides the basis for measuring the partial pressure of oxygen (pO(2)) and oxygen depletion rate (R) in the lungs. Precise measurements of this type are difficult because the oxygen effect manifests itself through a decay of signal, leading to noisy images at the end of the series. The depolarization caused by RF excitation pulses further complicates the problem. It is therefore important to optimize scan parameters, such as measurement timing and flip angle, to obtain accurate and reproducible measurements. This work presents a new single-acquisition technique in conjunction with the multiple regression fitting method for data evaluation. Analytical expressions for the measurement uncertainties are derived. A total of four types of single-acquisition timing schemes are investigated; simulation shows a large uncertainty variation between these schemes (pO(2): 7.5-30.2%; R: 47.4-173.7%). A basic procedure for optimizing scan parameters is then described. A phantom experiment was conducted to verify the simulation results. Repeated in vivo measurements with the optimal scheme in a rabbit experiment showed that average variation of global mean is 6.2% for pO(2) and 12.0% for R, and that the average variation of percentiles (10th, 25th, 50th, 75th, and 90th) is 8.7% for pO(2) and 19.0% for R.
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Affiliation(s)
- Jiangsheng Yu
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Yu J, Ishii M, Kadlecek S, Lipson DA, Emami K, Clark TW, Rajaei S, Rizi RR. Multiple regression method for pulmonary apparent diffusion coefficient measurement by hyperpolarized 3He MRI. J Magn Reson Imaging 2007; 25:982-91. [PMID: 17457799 DOI: 10.1002/jmri.20901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To develop and validate a new multiple regression technique for the separation of flip angle effect in pulmonary apparent diffusion coefficient (ADC) measurement. MATERIALS AND METHODS Hyperpolarized (3)He MRI (HP (3)He MRI) ADC measurements were performed on phantom, pig, and human models. The diffusion-sensitization sequence is modified from a standard gradient echo (GRE) sequence with a nonlinear progression in the bipolar gradient amplitude with each image. In the self-diffusion phantom experiment, four images were acquired with base gradient factor b(0) = 0.15 second/cm(2); in the pig and human experiment, six images were acquired with base gradient factor b(0) = 1.4 second/cm(2). RESULTS The self-diffusion coefficient measured in the phantom experiment was 1.98 +/- 0.16 cm(2)/second. The measured uncertainty curve was consistent with the theoretically predicted curve. The measured in vivo ADC values (three coronal slices in the supine direction) were 0.20/0.16/0.13 cm(2)/second and 0.20/0.18/0.16 cm(2)/second for pig and human experiments, respectively. CONCLUSION With the introduction of a nonlinear progression in the diffusion-sensitization gradients, the multiple regression technique is capable of separating the flip angle effect in ADC measurement. In addition, this technique can perform a rigorous measurement uncertainty analysis and provide the optimal scan parameters that yield best noise performance.
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Affiliation(s)
- Jiangsheng Yu
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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Wild JM, Teh K, Woodhouse N, Paley MNJ, Fichele S, de Zanche N, Kasuboski L. Steady-state free precession with hyperpolarized 3He: experiments and theory. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 183:13-24. [PMID: 16890464 DOI: 10.1016/j.jmr.2006.07.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 07/12/2006] [Accepted: 07/12/2006] [Indexed: 05/11/2023]
Abstract
The magnetization response of hyperpolarized 3He gas to a steady-state free precession (SSFP) sequence was simulated using matrix product operators. The simulations included the effects of flip angle (alpha), sequence timings, resonant frequency, gas diffusion coefficient, imaging gradients, T1 and T2. Experiments performed at 1.5 T, on gas phantoms and with healthy human subjects, confirm the predicted theory, and indicate increased SNR with SSFP through use of higher flip angles when compared to optimized spoiled gradient echo (SPGR). Simulations and experiments show some compromise to the SNR and some point spread function broadening at high alpha due to the incomplete refocusing of transverse magnetization, caused by diffusion dephasing from the readout gradient. Mixing of gas polarization levels by diffusion between slices is also identified as a source of signal loss in SSFP at higher alpha through incomplete refocusing. Nevertheless, in the sample experiments, a SSFP sequence with an optimized flip angle of alpha=20 degrees, and 128 sequential phase encoding views, showed a higher SNR when compared to SPGR (alpha=7.2 degrees) with the same bandwidth. Some of the gas sample experiments demonstrated a transient signal response that deviates from theory in the initial phase. This was identified as being caused by radiation damping interactions between the large initial transverse magnetization and the high quality factor (Q=250) birdcage resonator. In 3He NMR experiments, performed without imaging gradients, diffusion dephasing can be mitigated, and the effective T2 is relatively long (1 s). Under these circumstances the SSFP sequence behaves like a CPMG sequence with sinalpha/2 weighting of SNR. Experiments and simulations were also performed to characterize the off-resonance behaviour of the SSFP HP 3He signal. Characteristic banding artifacts due to off-resonance harmonic beating were observed in some of the in vivo SSFP images, for instance in axial slices close to the diaphragm where B0 inhomogeneity is highest. Despite these artifacts, a higher SNR was observed with SSFP in vivo when compared to the SPGR sequence. The trends predicted by theory of increasing SSFP SNR with increasing flip angle were observed in the range alpha=10-20 degrees without compromise to image quality through blurring caused by excessive k-space filtering.
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Affiliation(s)
- Jim M Wild
- Unit of Academic Radiology, University of Sheffield, C floor, Royal Hallamshire Hospital, Glossop Road, S10 2JF, UK.
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Morbach AE, Gast KK, Schmiedeskamp J, Herweling A, Windirsch M, Dahmen A, Ley S, Heussel CP, Heil W, Kauczor HU, Schreiber WG. [Microstructure of the lung: diffusion measurement of hyperpolarized 3Helium]. Z Med Phys 2006; 16:114-22. [PMID: 16875024 DOI: 10.1078/0939-3889-00303] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Imaging methods to study the lung are traditionally based on x-ray or on radioactive contrast agents. Conventional magnetic resonance imaging (MRI) has only limited applications for lung imaging because of the low tissue density of protons concentration of hydrogen atoms, which are usually the basis for the imaging. The introduction of hyperpolarized noble gases as a contrast agent in MRI has opened new possibilities for lung diagnosis. The present paper describes this new technique. Diffusion-weighted MRI for assessment of the lung microstructure is presented here as an example of the new possibilities of functional imaging. Studies to determine the sensitivity of the diffusion measurement and regarding the correlation with traditionally established methods are also presented, along with results of the measurement of the reproducibility determined in a clinical pilot study on healthy volunteers and patients. Furthermore, a pilot measurement of the 3He diffusion tensor in the lung is presented.
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Affiliation(s)
- Andreas E Morbach
- Klinik und Poliklinik für Diagnostische und Interventionelle Radiologie, Bereich Medizinische Physik, Universitätsklinikum Mainz
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Waters B, Owers-Bradley J, Silverman M. Acinar structure in symptom-free adults by Helium-3 magnetic resonance. Am J Respir Crit Care Med 2006; 173:847-51. [PMID: 16439719 DOI: 10.1164/rccm.200411-1595oc] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE The apparent diffusion coefficient of hyperpolarized (3)He in the lungs has been shown to correlate directly in animal models with the peripheral airspace size and can detect changes in lung microstructure. OBJECTIVES To study in vivo the (3)He apparent diffusion coefficient and to demonstrate its sensitivity to changes in lung morphometry as a result of aging, exposure to cigarette smoke, and lung inflation. METHODS We assessed the variation in the diffusion of hyperpolarized (3)He gas in the lungs by magnetic resonance techniques. Spirometric lung volumes were recorded. MEASUREMENTS We measured the dependence of (3)He diffusion on age and on reported cigarette smoke exposure in 32 symptom-free adults. We also measured the dependence of the apparent diffusion coefficient on the degree of lung inflation. RESULTS In healthy never-smokers, the apparent diffusion coefficient increased with age from 0.115 to 0.155 cm(2) . s(-1) at 20 and 70 yr, respectively, increased linearly with lung inflation and was independent of individual's lung size after correcting for age. For active and passive smokers, the apparent diffusion coefficient increased by up to 40% compared with never-smokers with mean values significantly higher (p=0.016 and p=0.0007, respectively). CONCLUSIONS Peripheral airspace size increases with age and after exposure to smoke in healthy adults in agreement with previous histologic studies. We have confirmed in vivo that peripheral airspace size is independent of intersubject lung size.
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Affiliation(s)
- Barnaby Waters
- School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
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Fischer MC, Kadlecek S, Yu J, Ishii M, Emami K, Vahdat V, Lipson DA, Rizi RR. Measurements of regional alveolar oxygen pressure using hyperpolarized 3He MRI. Acad Radiol 2005; 12:1430-9. [PMID: 16253855 DOI: 10.1016/j.acra.2005.07.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 07/14/2005] [Accepted: 07/18/2005] [Indexed: 11/28/2022]
Abstract
RATIONALE AND OBJECTIVES The aim of this work is to review hyperpolarized (HP) helium-3 (3He) magnetic resonance imaging (MRI) methods to measure regional alveolar oxygen partial pressure (P(A)O2) and oxygen depletion rate (R) in the lung. We point out limitations of the methods and suggest improvements to increase their accuracy. MATERIALS AND METHODS P(A)O2 and R can be extracted from series of HP gas images acquired during breath hold by making use of the depolarizing effect of oxygen on HP gas. To separate oxygen-induced depolarization from other depolarizing effects, several techniques can be used. We review currently used techniques and point out their advantages and limitations. RESULTS We show that the precision of oxygen measurements depends on a variety of parameters and can vary within the measurement volume. Accuracy of the measurement also can be influenced by diffusion of oxygen and polarized 3He and generally is different for single-slice and multislice measurements. We present numerical simulations, phantom data, and in vivo data for illustration. CONCLUSION HP 3He MRI is a noninvasive, nonionizing, and repeatable imaging method that allows for quantitative analysis of lung function. The current techniques for measuring P(A)O2 have the potential to deliver clinically relevant functional images.
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Affiliation(s)
- Martin C Fischer
- Department of Radiology, University of Pennsylvania School of Medicine, B1, Stellar-Chance Labs, Philadelphia, PA19104-6100, USA
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Fischer MC, Spector ZZ, Ishii M, Yu J, Emami K, Itkin M, Rizi R. Single-acquisition sequence for the measurement of oxygen partial pressure by hyperpolarized gas MRI. Magn Reson Med 2005; 52:766-73. [PMID: 15389934 DOI: 10.1002/mrm.20239] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Magnetic resonance imaging (MRI) with hyperpolarized 3-helium gas (HP 3He) offers the possibility of studying functional lung parameters such as the alveolar oxygen concentration and oxygen depletion rate. Until now, a double-acquisition technique has been utilized to extract these parameters. A complicated single-acquisition technique was previously developed to avoid the necessity of performing two identical breathing maneuvers. The results obtained with this technique were significantly less accurate than the results obtained with the double-acquisition method. In this work, a novel, easily implemented single-acquisition sequence is presented that provides results comparable to those obtained with the established double-acquisition method. This method is demonstrated in a phantom and a pig model on a 1.5 T scanner using a 2D fast low-angle shot (FLASH) gradient-echo sequence. Numerical simulations of the time evolution of the oxygen concentration were performed. Simulation results are presented to support the experimental data. Various parameter regimes were experimentally and numerically investigated.
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Affiliation(s)
- M C Fischer
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
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Rizi RR, Baumgardner JE, Ishii M, Spector ZZ, Edvinsson JM, Jalali A, Yu J, Itkin M, Lipson DA, Gefter W. Determination of regional VA/Q by hyperpolarized 3He MRI. Magn Reson Med 2004; 52:65-72. [PMID: 15236368 DOI: 10.1002/mrm.20136] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Alveolar ventilation/perfusion ratio (VA/Q) is a key parameter in functional imaging of the lung. Herein, regional VA/Q was calculated from regional values of alveolar partial pressure of oxygen (PAO2) measured by hyperpolarized 3He gas MRI (HP 3He MRI). Yorkshire pigs (n = 7, mean weight = 25 kg) were paralyzed and maintained under isoflurane anesthesia. Animals were placed into a birdcage coil, then transferred to the bore of a 1.5 T MRI unit. Prior to imaging, animals were manually ventilated with room air for 5 min, then a 3He gas mixture was administered during breathhold and imaging performed. PAO2 was measured based on the decay rate of 3He signal. Subjects' blood gas concentrations were measured and these values and PAO2 values entered into a system of four equations with four unknowns. Calculated VA/Q values were analyzed by preparing frequency distributions for the entire lung and compared to VA/Q frequency distributions previously established in the literature as normal using other diagnostic techniques. Distributions were consistent with those in the literature, indicating that HP 3He MRI may be an accurate, quantitative, noninvasive, and nonradioactive method for acquiring VA/Q for small regions of the lung.
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Affiliation(s)
- Rahim R Rizi
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA.
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36
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Spector ZZ, Emami K, Fischer MC, Zhu J, Ishii M, Yu J, Kadlecek S, Driehuys B, Panettieri RA, Lipson DA, Gefter W, Shrager J, Rizi RR. A small animal model of regional alveolar ventilation using HP 3He MRI1. Acad Radiol 2004; 11:1171-9. [PMID: 15530811 DOI: 10.1016/j.acra.2004.08.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Accepted: 06/30/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE AND OBJECTIVES The aim of this study was to establish a standardized procedure for the measurement of regional fractional ventilation in a healthy rat model as a baseline for further studies of pulmonary disorder models. MATERIALS AND METHODS The lungs of five healthy male Sprague-Dawley rats were imaged using hyperpolarized helium-3 magnetic resonance imaging. From these images, regional fractional ventilation was calculated and maps generated detailing the distribution of fractional ventilation in the lung. The 1.56 mm x 1.56 mm x 4 mm regions of interest were assigned on 5 cm x 5 cm field of view lung maps. Histograms were also generated showing the frequency distribution of fractional ventilation values. To compare fractional ventilation values between animals, the ventilation procedure was standardized to results from individual pulmonary function tests. Each animal's spontaneous tidal volume, respiratory rate, and inspiration percentage (percent of total respiratory cycle in inspiration) were used in their mechanical ventilation settings. RESULTS Results were similar among all five healthy rats based on examination of ventilation distribution maps and frequency distribution histograms. Mean (0.13) and standard deviation (0.07) were calculated for fractional ventilation in each animal. However, these values were determined to be influenced by slice selection, and therefore the maps and histograms were favored in analysis of results. CONCLUSION This study shows consistent results in healthy rat lungs and will serve as a baseline study for future measurements in emphysematous rat lungs.
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Affiliation(s)
- Z Z Spector
- Department of Radiology, University of Pennsylvania School of Medicine, Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA 19104, USA
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Wang B, Saha PK, Udupa JK, Ferrante MA, Baumgardner J, Roberts DA, Rizi RR. 3D airway segmentation via hyperpolarized 3He gas MRI by using scale-based fuzzy connectedness. Comput Med Imaging Graph 2004; 28:77-86. [PMID: 15127752 DOI: 10.1016/j.compmedimag.2003.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Computerized segmentation of 3D tracheobronchial tree is a necessary first step for subsequent registration and analysis of pulmonary airway and vascular magnetic resonance (MR) images obtained by using hyperpolarized 3Helium gas and Gadolinium. The scientific and clinical implications of acquiring these data on the tracheobronchial tree (for studying ventilation, V) and on the coinciding pulmonary arterioles (for studying perfusion, Q), is the next frontier for static and dynamic pulmonary MRI. In this paper, we report an airway segmentation method from 3He MR images based on the scale-based fuzzy connectedness approach. Incorporated in this method are the pre-processing steps of inhomogeneity correction and intensity standardization. The basic sequential steps in the proposed airway segmentation method are: (1) image acquisition, (2) radio frequency field inhomogeneity correction, (3) standardization of MR image intensity scale, (4) seed specification, (5) scale-based fuzzy connected segmentation of airways, and (6) thresholding and binarization. The majority of these steps are automatically executed; others allow interaction through a graphical interface provided in the 3DVIEWNIX software system, in which the algorithms are implemented. The method achieves an overall precision of about 98% in terms of the extent of overlap in repeated segmentations. Its level of accuracy can be described by a true positive volume fraction of about 98% (considering manual delineation as the surrogate of true delineation), and a false negative and positive volume fraction of about 1%. The total operator and computational time required per study are on the average 2 and 20 min.
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Affiliation(s)
- Binquan Wang
- BI, Stellar-Chance Laboratories, Metabolic Magnetic Resonance Research and Computing Center, Department of Radiology, Hospital of the University of Pennsylvania, 422 Curie Boulevard, Philadelphia, PA 19104, USA
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Golman K, Olsson LE, Axelsson O, Månsson S, Karlsson M, Petersson JS. Molecular imaging using hyperpolarized13C. Br J Radiol 2003; 76 Spec No 2:S118-27. [PMID: 15572334 DOI: 10.1259/bjr/26631666] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
MRI provides unsurpassed soft tissue contrast, but the inherent low sensitivity of this modality has limited the clinical use to imaging of water protons. With hyperpolarization techniques, the signal from a given number of nuclear spins can be raised more than 100 000 times. The strong signal enhancement enables imaging of nuclei other than protons, e.g. (13)C and (15)N, and their molecular distribution in vivo can be visualized in a clinically relevant time window. This article reviews different hyperpolarization techniques and some of the many application areas. As an example, experiments are presented where hyperpolarized (13)C nuclei have been injected into rabbits, followed by rapid (13)C MRI with high spatial resolution (scan time <1 s and 1.0 mm in-plane resolution). The high degree of polarization thus enabled mapping of the molecular distribution within various organs, a few seconds after injection. The hyperpolarized (13)C MRI technique allows a selective identification of the molecules that give rise to the MR signal, offering direct molecular imaging.
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Affiliation(s)
- K Golman
- Amersham Health R&D AB, Medeon, SE-205 12 Malmö, Sweden
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Hasegawa I, Uematsu H, Gee JC, Rogelj P, Song HK, Nakatsu M, Takahashi M, Gefter WB, Hatabu H. Voxelwise mapping of magnetic resonance ventilation-perfusion ratio in a porcine model by multimodality registration: technical note1. Acad Radiol 2003; 10:1091-6. [PMID: 14587627 DOI: 10.1016/s1076-6332(03)00142-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
RATIONALE AND OBJECTIVES The purpose of this study was to demonstrate the construction of voxelwise ventilation-perfusion (V/Q) ratio maps in a porcine model by nonrigidly aligning the respective ventilation and perfusion images using a multimodality registration algorithm. MATERIALS AND METHODS The first-pass contrast agent technique for a blood flow map and 3He used for ventilation imaging were performed using a normal porcine model. The registered 3He-ventilation image was then aligned to the blood flow map using a multimodality registration algorithm. The voxelwise V/Q ratios were calculated by dividing the registered 3He-ventilation image by the blood flow map. The V/Q ratios were also semi-logarithmically scatter-plotted against the number of voxels. RESULTS From perfusion magnetic resonance images, a voxel-by-voxel blood flow map was produced. Registered 3He ventilation image was successfully obtained as well as V/Q ratio map. Plots of the V/Q ratios obtained by this registration approach were similar to the logarithmic normal distribution. CONCLUSION Registration of MR perfusion and ventilation images can potentially enable quantitative evaluation of regional pulmonary function and thus yield deeper insight into the physiology and pathophysiology of the lung.
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Affiliation(s)
- Ichiro Hasegawa
- Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA
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40
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Gast KK, Eberle B, Schmiedeskamp J, Kauczor HU. Magnetic resonance imaging using hyperpolarized 3He-gas1. Acad Radiol 2003; 10:1119-31. [PMID: 14587630 DOI: 10.1016/s1076-6332(03)00335-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
RATIONALE AND OBJECTIVES Current imaging procedures of the lung concentrate on visualization of morphology. Computed tomography is the imaging method of choice for the majority of pulmonary diseases. Functional data are commonly obtained from arterial blood gas analysis, spirometry, and body plethysmography, which all suffer from lack of regional information. MATERIALS AND METHODS Magnetic resonance imaging (MRI) of the lung has been advanced recently by the use of hyperpolarized 3He as a new contrast mechanism. Four different image acquisition modes are performed during a typical patient study. RESULTS 3He-MRI yields functional information about the lung with a high spatial and temporal resolution, avoiding the risks of ionizing radiation. The method is currently limited by high costs and restricted availability of the gas. CONCLUSION In this article, the experience obtained at the University of Mainz, being Europe's most experienced center performing 3He-MRI in humans, is reviewed against the international background.
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Affiliation(s)
- Klaus Kurt Gast
- Kliniks fuer Radiologie and Anaesthesiologie, Klinikum Universitaet Mainz, Germany
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41
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Dupuich D, Berthezène Y, Clouet PL, Stupar V, Canet E, Crémillieux Y. Dynamic3He imaging for quantification of regional lung ventilation parameters. Magn Reson Med 2003; 50:777-83. [PMID: 14523964 DOI: 10.1002/mrm.10590] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Dynamic ventilation imaging using laser-polarized (3)He has a promising potential for elucidating the physiology and physiopathology of the lungs. In this study, a methodological approach is proposed for the assessment and quantification of local ventilation parameters. High-temporal-resolution coronal ventilation image series were obtained with a projection-reconstruction (PR) sequence combined with the sliding-window technique. After image series were processed, parametric pixel-by-pixel maps of the gas arrival time, filling time constant, inflation rate, and gas volume were generated. The acquisition technique and the signal processing procedure, which are referred to collectively as sliding pulmonary imaging for respiratory overview (SPIRO), were tested in vivo in healthy rat lungs using a contrast media injector for controlled (3)He flow and volume injection in the animal lungs. The same protocol was applied to broncho-constriction animal models using intravenous injection of methacholine solution. Inflation rate values measured in the lungs were found to decrease with increasing doses of injected methacholine solution. This study demonstrates that it is possible to obtain quantitative regional gas dynamic information using the SPIRO technique in a single polarized gas inspiration.
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Affiliation(s)
- David Dupuich
- Laboratoire de RMN, CNRS 5012, Université Lyon-1, Villeurbanne, France
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42
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Mills GH, Wild JM, Eberle B, Van Beek EJR. Functional magnetic resonance imaging of the lung. Br J Anaesth 2003; 91:16-30. [PMID: 12821562 DOI: 10.1093/bja/aeg149] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- G H Mills
- Unit of Academic Anaesthesia, University of Sheffield and The Directorate of Critical Care Medicine, Royal Hallamshire Hospital, Glossop Road, UK.
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Svensson J. Contrast-enhanced magnetic resonance angiography: development and optimization of techniques for paramagnetic and hyperpolarized contrast media. Acta Radiol 2003; 429:1-30. [PMID: 12757468 DOI: 10.1034/j.1600-0455.44.s.429.1.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Contrast-enhanced magnetic resonance angiography (CE-MRA) is a diagnostic method for imaging of vascular structures based on nuclear magnetic resonance. Vascular enhancement is achieved by injection of a contrast medium (CM). Studies were performed using two different types of CM: conventional paramagnetic CM, and a new type of CM based on hyperpolarized (HP) nuclei. The effects of varying CM concentration with time during image acquisition were studied by means of computer simulations using two different models. It was shown that a rapid concentration variation during encoding of the central parts of k-space could result in signal loss and severe image artifacts. The results were confirmed qualitatively with phantom experiments. A postprocessing method was developed to address problems with simultaneous enhancement of arteries and veins in CE-MRA of the lower extremities. The method was based on the difference in flow-induced phase in the two vessel types. Evaluation of the method was performed with flow phantom measurements and with CE-MRA in two volunteers using standard pulse sequences. The flow-induced phase in the vessels of interest was sufficient to distinguish arteries from veins in the superior-inferior direction. Using this method, the venous enhancement could be extinguished. The possibility of using HP nuclei as CM for CE-MRA was evaluated. Signal expressions for a flow of HP CM imaged with a gradient echo sequence were derived. These signal expressions were confirmed in phantom experiments using HP 129Xe dissolved in ethanol. Studies were also performed with a new CM based on HP 13C. The CM had very long relaxation times (T1, in vivo/T2, in vivo approximately 38/1.3 s). The long relaxation times were utilized in imaging with a fully balanced steady-state free precession pulse sequence (trueFISP), where the optimal flip angle was found to be 180 degrees. CE-MRA with the 13C-based CM in rats resulted in images with high vascular SNR (approximately 500). CE-MRA is a useful clinical tool for diagnosing vascular disease. With the development of new contrast media, based on hyperpolarized nuclei for example, there is a potential for further improvement in the signal levels that can be achieved, enabling a standard of imaging of vessels that is not possible today.
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Affiliation(s)
- Jonas Svensson
- Department of Radiation Physics, Institute of Radiology and Physiology, Malmö, Malmö University Hospital, Lund University, SE-205 02 Malmö, Sweden
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Bidinosti CP, Choukeife J, Nacher PJ, Tastevin G. In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 162:122-132. [PMID: 12762989 DOI: 10.1016/s1090-7807(02)00198-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present NMR measurements of the diffusion of hyperpolarized 3He in the human lung performed at fields much lower than those of conventional MRI scanners. The measurements were made on standing subjects using homebuilt apparatus operating at 3mT. O(2)-limited transverse relaxation (T(2) up to 15-35s) could be measured in vivo. Accurate global diffusion measurements have been performed in vivo and in a plastic bag; the average apparent diffusion coefficient (ADC) in vivo was 14.2+/-0.6mm(2)/s, whereas the diffusion coefficient in the bag (3He diluted in N(2)) was 79.5+/-1mm(2)/s. 1D ADC mapping with high SNR ( approximately 200-300) demonstrates the real possibility of performing quality lung imaging at extremely low fields.
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Golman K, Ardenkjaer-Larsen JH, Svensson J, Axelsson O, Hansson G, Hansson L, Jóhannesson H, Leunbach I, Månsson S, Petersson JS, Pettersson G, Servin R, Wistrand LG. 13C-angiography. Acad Radiol 2002; 9 Suppl 2:S507-10. [PMID: 12188323 DOI: 10.1016/s1076-6332(03)80278-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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46
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Markstaller K, Kauczor HU, Puderbach M, Mayer E, Viallon M, Gast K, Weiler N, Thelen M, Eberle B. 3He-MRI-based vs. conventional determination of lung volumes in patients after unilateral lung transplantation: a new approach to regional spirometry. Acta Anaesthesiol Scand 2002; 46:845-52. [PMID: 12139541 DOI: 10.1034/j.1399-6576.2002.460715.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND To use 3Helium (3He)-MRI in patients with unilateral lung grafts to assess the contributions of graft and native lung to total ventilated lung volume, and second to compare conventional measurements of intrapulmonary gas volume (spirometry, body plethysmography) with image-based volumetry of ventilated lung parenchyma visualized by hyperpolarized 3He-MRI. METHODS With Ethics Committee approval, five patients with single lung transplantation (SLTX) for idiopathic pulmonary fibrosis (IPF) underwent both conventional pulmonary function testing (PFT) and 3He-MRI of the lung. Intrapulmonary gas volume (GV) during the inspiratory breathhold for 3He-MRI was calculated from measured functional residual capacity (corrected for supine position) and inspired tidal volume. Image-based global and regional lung volumetries (LV) were performed in three-dimensionally reconstructed 3He-MR images (corrected for the fraction of tissue and blood). RESULTS Transplanted lungs were characterized by a homogeneous distribution of signal intensity, whereas the native lungs of the patients suffering from IPF displayed an inhomogeneous signal distribution pattern with numerous round or wedge-shaped ventilation defects. Total ventilated lung volume determined by 3He-MRI correlated well with PFT-based measurements, but with a systematic overestimation of the 3He-based lung volumetry of approximately 20%. Functioning lung grafts contributed 66+/-6% and their corresponding native IPF lungs 34+/-6% to total ventilated volume (P<0.05; mean+/-SD). CONCLUSION 3Helium-MRI of the lung offers a novel approach to regional determination of ventilated lung volume, including its blood and tissue compartments. The advantage of this technique over computed tomography or ventilation scintigraphy is the lack of radiation exposure, and hence its repeatability. Follow up of SLTX patients with this new technique may allow the monitoring of functional and structural developments of grafted lungs with better sensitivity and specificity than PFT.
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Affiliation(s)
- K Markstaller
- Department of Anaesthesiology, Johannes Gutenberg-University Medical School, Mainz, Germany.
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Möller HE, Chen XJ, Saam B, Hagspiel KD, Johnson GA, Altes TA, de Lange EE, Kauczor HU. MRI of the lungs using hyperpolarized noble gases. Magn Reson Med 2002; 47:1029-51. [PMID: 12111949 DOI: 10.1002/mrm.10173] [Citation(s) in RCA: 273] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The nuclear spin polarization of the noble gas isotopes (3)He and (129)Xe can be increased using optical pumping methods by four to five orders of magnitude. This extraordinary gain in polarization translates directly into a gain in signal strength for MRI. The new technology of hyperpolarized (HP) gas MRI holds enormous potential for enhancing sensitivity and contrast in pulmonary imaging. This review outlines the physics underlying the optical pumping process, imaging strategies coping with the nonequilibrium polarization, and effects of the alveolar microstructure on relaxation and diffusion of the noble gases. It presents recent progress in HP gas MRI and applications ranging from MR microscopy of airspaces to imaging pulmonary function in patients and suggests potential directions for future developments.
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Affiliation(s)
- Harald E Möller
- Max-Planck-Institut für neuropsychologische Forschung, Leipzig, Germany.
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Venkatesh AK, Zhao L, Balamore D, Jolesz FA, Albert MS. Hyperpolarized 129Xe MRI using gas-filled liposomes. Acad Radiol 2002; 9 Suppl 1:S270-4. [PMID: 12019887 DOI: 10.1016/s1076-6332(03)80454-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Arvind K Venkatesh
- Department of Radiology/MRI, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Wild JM, Paley MNJ, Viallon M, Schreiber WG, van Beek EJR, Griffiths PD. k-space filtering in 2D gradient-echo breath-hold hyperpolarized 3He MRI: spatial resolution and signal-to-noise ratio considerations. Magn Reson Med 2002; 47:687-95. [PMID: 11948729 DOI: 10.1002/mrm.10134] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this work some of the factors that can influence the signal-to-noise ratio (SNR) and spatial resolution in MR images of inhaled hyperpolarized gases are systematically addressed. In particular, the effects of RF depletion of longitudinal polarization and image gradient diffusion dephasing were assessed in terms of their contribution to a k-space filter. By means of theoretical simulations and a novel method of experimental validation using a variable transverse magnetization of the 1H signal, systematic quantitative and qualitative investigations of the effects of k-space filtering intrinsic to imaging of hyperpolarized gas were made. A 2D gradient-echo image is considered for a range of flip angles with centric, sequential, and half-Fourier Cartesian phase-encoding strategies, and the results are assessed in terms of SNR and spatial resolution in the reconstructed images. Centric phase encoding was found to give the best SNR at higher flip angles, with a trade-off in spatial resolution compared to sequential phase encoding. A half-Fourier approach potentially offers increased SNR through the use of higher flip angles without compromising the spatial resolution, which is comparable to that achieved with sequential encoding.
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Affiliation(s)
- Jim M Wild
- Section of Academic Radiology, Royal Hallamshirw Hospital, University of Sheffield, Sheffield, UK.
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Goodson BM. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials, and organisms. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 155:157-216. [PMID: 12036331 DOI: 10.1006/jmre.2001.2341] [Citation(s) in RCA: 299] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The sensitivity of conventional nuclear magnetic resonance (NMR) techniques is fundamentally limited by the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This review describes the principles and magnetic resonance applications of laser-polarized noble gases. The enormous sensitivity enhancement afforded by optical pumping can be exploited to permit a variety of novel NMR experiments across numerous disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, NMR sensitivity enhancement via polarization transfer, and low-field NMR and MRI.
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Affiliation(s)
- Boyd M Goodson
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California, Berkeley 94720-1460, USA
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