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Li Z, Xiao S, Wang C, Li H, Zhao X, Duan C, Zhou Q, Rao Q, Fang Y, Xie J, Shi L, Guo F, Ye C, Zhou X. Encoding Enhanced Complex CNN for Accurate and Highly Accelerated MRI. IEEE TRANSACTIONS ON MEDICAL IMAGING 2024; 43:1828-1840. [PMID: 38194397 DOI: 10.1109/tmi.2024.3351211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Magnetic resonance imaging (MRI) using hyperpolarized noble gases provides a way to visualize the structure and function of human lung, but the long imaging time limits its broad research and clinical applications. Deep learning has demonstrated great potential for accelerating MRI by reconstructing images from undersampled data. However, most existing deep convolutional neural networks (CNN) directly apply square convolution to k-space data without considering the inherent properties of k-space sampling, limiting k-space learning efficiency and image reconstruction quality. In this work, we propose an encoding enhanced (EN2) complex CNN for highly undersampled pulmonary MRI reconstruction. EN2 complex CNN employs convolution along either the frequency or phase-encoding direction, resembling the mechanisms of k-space sampling, to maximize the utilization of the encoding correlation and integrity within a row or column of k-space. We also employ complex convolution to learn rich representations from the complex k-space data. In addition, we develop a feature-strengthened modularized unit to further boost the reconstruction performance. Experiments demonstrate that our approach can accurately reconstruct hyperpolarized 129Xe and 1H lung MRI from 6-fold undersampled k-space data and provide lung function measurements with minimal biases compared with fully sampled images. These results demonstrate the effectiveness of the proposed algorithmic components and indicate that the proposed approach could be used for accelerated pulmonary MRI in research and clinical lung disease patient care.
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Klimeš F, Obert AJ, Scheller J, Wernz MM, Voskrebenzev A, Gutberlet M, Grimm R, Suhling H, Müller RA, Kaireit TF, Glandorf J, Moher Alsady T, Wacker F, Vogel-Claussen J. Comparison of Free-Breathing 3D Phase-Resolved Functional Lung (PREFUL) MRI With Dynamic 19 F Ventilation MRI in Patients With Obstructive Lung Disease and Healthy Volunteers. J Magn Reson Imaging 2024. [PMID: 38214459 DOI: 10.1002/jmri.29221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/13/2024] Open
Abstract
BACKGROUND Non-contrast-enhanced 1 H magnetic resonance imaging (MRI) with full lung coverage shows promise for assessment of regional lung ventilation but a comparison with direct ventilation measurement using 19 F MRI is lacking. PURPOSE To compare ventilation parameters calculated using 3D phase-resolved functional lung (PREFUL) MRI with 19 F MRI. STUDY TYPE Prospective. POPULATION Fifteen patients with asthma, 14 patients with chronic obstructive lung disease, and 13 healthy volunteers. FIELD STRENGTH/SEQUENCE A 3D gradient-echo pulse sequence with golden-angle increment and stack-of-stars encoding at 1.5 T. ASSESSMENT All participants underwent 3D PREFUL MRI and 19 F MRI. For 3D PREFUL, static regional ventilation (RVent) and dynamic flow-volume cross-correlation metric (FVL-CM) were calculated. For both parameters, ventilation defect percentage (VDP) values and ventilation defect (VD) maps (including a combination of both parameters [VDPCombined ]) were determined. For 19 F MRI, images from eight consecutive breaths under volume-controlled inhalation of perfluoropropane were acquired. Time-to-fill (TTF) and wash-in (WI) parameters were extracted. For all 19 F parameters, a VD map was generated and the corresponding VDP values were calculated. STATISTICAL TESTS For all parameters, the relationship between the two techniques was assessed using a Spearman correlation (r). Differences between VDP values were compared using Bland-Altman analysis. For regional comparison of VD maps, spatial overlap and Sørensen-Dice coefficients were computed. RESULTS 3D PREFUL VDP values were significantly correlated to VDP measures by 19 F (r range: 0.59-0.70). For VDPRVent , no significant bias was observed with VDP of the third and fourth breath (bias range = -6.8:7.7%, P range = 0.25:0.30). For VDPFVL-CM , no significant bias was found with VDP values of fourth-eighth breaths (bias range = -2.0:12.5%, P range = 0.12:0.75). The overall spatial overlap of all VD maps increased with each breath, ranging from 61% to 81%, stabilizing at the fourth breath. DATA CONCLUSION 3D PREFUL MRI parameters showed moderate to strong correlation with 19 F MRI. Depending on the 3D PREFUL VD map, the best regional agreement was found to 19 F VD maps of third-fifth breath. LEVEL OF EVIDENCE 3 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Filip 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
| | - Arnd J Obert
- Department of Radiation Oncology, University Hospital Würzburg, Würzburg, Germany
| | - Julienne Scheller
- 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
| | - Marius M Wernz
- 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
| | - Andreas 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
| | - Marcel 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
| | - Robert Grimm
- MR Application Predevelopment, Siemens Healthineers AG, Erlangen, Germany
| | - Hendrik Suhling
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
- Department of Respiratory Medicine, Hannover Medical School, Hanover, Germany
| | - Robin A Müller
- 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
| | - Till 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
| | - Julian Glandorf
- 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
| | - Tawfik Moher Alsady
- 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
| | - Frank 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
| | - Jens 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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Babaeipour R, Ouriadov A, Fox MS. Deep Learning Approaches for Quantifying Ventilation Defects in Hyperpolarized Gas Magnetic Resonance Imaging of the Lung: A Review. Bioengineering (Basel) 2023; 10:1349. [PMID: 38135940 PMCID: PMC10740978 DOI: 10.3390/bioengineering10121349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/06/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
This paper provides an in-depth overview of Deep Neural Networks and their application in the segmentation and analysis of lung Magnetic Resonance Imaging (MRI) scans, specifically focusing on hyperpolarized gas MRI and the quantification of lung ventilation defects. An in-depth understanding of Deep Neural Networks is presented, laying the groundwork for the exploration of their use in hyperpolarized gas MRI and the quantification of lung ventilation defects. Five distinct studies are examined, each leveraging unique deep learning architectures and data augmentation techniques to optimize model performance. These studies encompass a range of approaches, including the use of 3D Convolutional Neural Networks, cascaded U-Net models, Generative Adversarial Networks, and nnU-net for hyperpolarized gas MRI segmentation. The findings highlight the potential of deep learning methods in the segmentation and analysis of lung MRI scans, emphasizing the need for consensus on lung ventilation segmentation methods.
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Affiliation(s)
- Ramtin Babaeipour
- School of Biomedical Engineering, Faculty of Engineering, The University of Western Ontario, London, ON N6A 3K7, Canada;
| | - Alexei Ouriadov
- School of Biomedical Engineering, Faculty of Engineering, The University of Western Ontario, London, ON N6A 3K7, Canada;
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada;
- Lawson Health Research Institute, London, ON N6C 2R5, Canada
| | - Matthew S. Fox
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada;
- Lawson Health Research Institute, London, ON N6C 2R5, Canada
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Shammi UA, D'Alessandro MF, Altes T, Hersman FW, Ruset IC, Mugler J, Meyer C, Mata J, Qing K, Thomen R. Comparison of Hyperpolarized 3He and 129Xe MR Imaging in Cystic Fibrosis Patients. Acad Radiol 2022; 29 Suppl 2:S82-S90. [PMID: 33487537 DOI: 10.1016/j.acra.2021.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/24/2020] [Accepted: 01/06/2021] [Indexed: 12/29/2022]
Abstract
PURPOSE In this study, we compared hyperpolarized 3He and 129Xe images from patients with cystic fibrosis using two commonly applied magnetic resonance sequences, standard gradient echo (GRE) and balanced steady-state free precession (TrueFISP) to quantify regional similarities and differences in signal distribution and defect analysis. MATERIALS AND METHODS Ten patients (7M/3F) with cystic fibrosis underwent hyperpolarized gas MR imaging with both 3He and 129Xe. Six had MRI with both GRE, and TrueFISP sequences and four patients had only GRE sequence but not TrueFISP. Ventilation defect percentages (VDPs) were calculated as lung voxels with <60% of the whole-lung hyperpolarized gas signal mean and was measured in all datasets. The voxel signal distributions of both 129Xe and 3He gases were visualized and compared using violin plots. VDPs of hyperpolarized 3 He and 129 Xe were compared in Bland-Altman plots; Pearson correlation coefficients were used to evaluate the relationships between inter-gas and inter-scan to assess the reproducibility. RESULTS A significant correlation was demonstrated between 129Xe VDP and 3He VDP for both GRE and TrueFISP sequences (ρ = 0.78, p<0.0004). The correlation between the GRE and TrueFISP VDP for 3He was ρ = 0.98 and was ρ = 0.91 for 129Xe. Overall, 129Xe (27.2±9.4) VDP was higher than 3He (24.3±6.9) VDP on average on cystic fibrosis patients. CONCLUSION In patients with cystic fibrosis, the selection of hyperpolarized 129Xe or 3He gas is most likely inconsequential when it comes to measure the overall lung function by VDP although 129Xe may be more sensitive to starker lung defects, particularly when using a TrueFISP sequence.
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Affiliation(s)
- Ummul Afia Shammi
- Biomedical, Biological, and Chemical Engineering, University of Missouri, Columbia, Missouri
| | | | - Talissa Altes
- Radiology, School of Medicine, University of Missouri, Columbia, Missouri
| | | | | | - John Mugler
- Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia; Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Craig Meyer
- Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia; Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Jamie Mata
- Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Kun Qing
- Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Robert Thomen
- Biomedical, Biological, and Chemical Engineering, University of Missouri, Columbia, Missouri; Radiology, School of Medicine, University of Missouri, Columbia, Missouri.
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Gerald Teague W, Mata J, Qing K, Tustison NJ, Mugler JP, Meyer CH, de Lange EE, Shim YM, Wavell K, Altes TA. Measures of ventilation heterogeneity mapped with hyperpolarized helium-3 MRI demonstrate a T2-high phenotype in asthma. Pediatr Pulmonol 2021; 56:1440-1448. [PMID: 33621442 PMCID: PMC8137549 DOI: 10.1002/ppul.25303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 12/02/2020] [Accepted: 01/07/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Hyperpolarized gas with helium (HHe-3) MR (magnetic resonance) is a noninvasive imaging method which maps and quantifies regions of ventilation heterogeneity (VH) in the lung. VH is an important feature of asthma, but little is known as to how VH informs patient phenotypes. PURPOSE To determine if VH indicators quantified by HHe-3 MR imaging (MRI) predict phenotypic characteristics and map to regions of inflammation in children with problematic wheeze or asthma. METHODS Sixty children with poorly-controlled wheeze or asthma underwent HHe-3 MRI, including 22 with bronchoalveolar lavage (BAL). The HHe-3 signal intensity defined four ventilation compartments. The non-ventilated and hypoventilated compartments divided by the total lung volume defined a VH index (VHI %). RESULTS Children with VHI % in the upper quartile had significantly greater airflow limitation, bronchodilator responsiveness, blood eosinophils, expired nitric oxide (FeNO), and BAL eosinophilic or neutrophilic granulocyte patterns compared to children with VHI % in the lower quartile. Lavage return from hypoventilated bronchial segments had greater eosinophil % than from ventilated segments. CONCLUSION In children with asthma, greater VHI % as measured by HHe-3 MRI identifies a severe phenotype with higher type 2 inflammatory markers, and maps to regions of lung eosinophilia. Listed on ClinicalTrials. gov (NCT02577497).
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Affiliation(s)
- W Gerald Teague
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Jaime Mata
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Kun Qing
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Nicholas J Tustison
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - John P Mugler
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Craig H Meyer
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - Eduard E de Lange
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Yun M Shim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Vorginia, USA
| | - Kristin Wavell
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Talissa A Altes
- Department of Radiology, University of Missouri School of Medicine, Columbia, Missouri, USA
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Brooke JP, Hall IP. Novel Thoracic MRI Approaches for the Assessment of Pulmonary Physiology and Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1304:123-145. [PMID: 34019267 DOI: 10.1007/978-3-030-68748-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Excessive pulmonary inflammation can lead to damage of lung tissue, airway remodelling and established structural lung disease. Novel therapeutics that specifically target inflammatory pathways are becoming increasingly common in clinical practice, but there is yet to be a similar stepwise change in pulmonary diagnostic tools. A variety of thoracic magnetic resonance imaging (MRI) tools are currently in development, which may soon fulfil this emerging clinical need for highly sensitive assessments of lung structure and function. Given conventional MRI techniques are poorly suited to lung imaging, alternate strategies have been developed, including the use of inhaled contrast agents, intravenous contrast and specialized lung MR sequences. In this chapter, we discuss technical challenges of performing MRI of the lungs and how they may be overcome. Key thoracic MRI modalities are reviewed, namely, hyperpolarized noble gas MRI, oxygen-enhanced MRI (OE-MRI), ultrashort echo time (UTE) MRI and dynamic contrast-enhanced (DCE) MRI. Finally, we consider potential clinical applications of these techniques including phenotyping of lung disease, evaluation of novel pulmonary therapeutic efficacy and longitudinal assessment of specific patient groups.
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Affiliation(s)
- Jonathan P Brooke
- Department of Respiratory Medicine, University of Nottingham, Queens Medical Centre, Nottingham, UK.
| | - Ian P Hall
- Department of Respiratory Medicine, University of Nottingham, Queens Medical Centre, Nottingham, UK.
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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: 27] [Impact Index Per Article: 9.0] [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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Goralski JL, Stewart NJ, Woods JC. Novel imaging techniques for cystic fibrosis lung disease. Pediatr Pulmonol 2021; 56 Suppl 1:S40-S54. [PMID: 32592531 PMCID: PMC7808406 DOI: 10.1002/ppul.24931] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/25/2020] [Indexed: 12/24/2022]
Abstract
With an increasing number of patients with cystic fibrosis (CF) receiving highly effective CFTR (cystic fibrosis transmembrane regulator protein) modulator therapy, particularly at a young age, there is an increasing need to identify imaging tools that can detect and regionally visualize mild CF lung disease and subtle changes in disease state. In this review, we discuss the latest developments in imaging modalities for both structural and functional imaging of the lung available to CF clinicians and researchers, from the widely available, clinically utilized imaging methods for assessing CF lung disease-chest radiography and computed tomography-to newer techniques poised to become the next phase of clinical tools-structural/functional proton and hyperpolarized gas magnetic resonance imaging (MRI). Finally, we provide a brief discussion of several newer lung imaging techniques that are currently available only in selected research settings, including chest tomosynthesis, and fluorinated gas MRI. We provide an update on the clinical and/or research status of each technique, with a focus on sensitivity, early disease detection, and possibilities for monitoring treatment efficacy.
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Affiliation(s)
- Jennifer L Goralski
- UNC Cystic Fibrosis Center, Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Division of Pulmonary and Critical Care Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Division of Pediatric Pulmonology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Neil J Stewart
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital, Cincinnati, Ohio.,Department of Infection, Immunity & Cardiovascular Disease, POLARIS Group, Imaging Sciences, University of Sheffield, Sheffield, UK
| | - Jason C Woods
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital, Cincinnati, Ohio.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio.,Department of Radiology, Cincinnati Children's Hospital, Cincinnati, Ohio
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9
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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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10
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Maunder A, Chan HF, Hughes PJC, Collier G, Norquay G, Rodgers O, Thelwall P, Robb F, Rao M, Wild JM. MR properties of 19 F C 3 F 8 gas in the lungs of healthy volunteers: T 2 ∗ and apparent diffusion coefficient at 1.5T and T 2 ∗ at 3T. Magn Reson Med 2020; 85:1561-1570. [PMID: 32926448 DOI: 10.1002/mrm.28511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/08/2020] [Accepted: 08/17/2020] [Indexed: 01/07/2023]
Abstract
PURPOSE To measure the transverse relaxation time ( T 2 ∗ ) and apparent diffusion coefficient (ADC) of 19 F-C3 F8 gas in vivo in human lungs at 1.5T and 3T, and to determine the representative distribution of values of these parameters in a cohort of healthy volunteers. METHODS Mapping of ADC at lung inflation levels of functional residual capacity (FRC) and total lung capacity (TLC) was performed with inhaled 19 F-C3 F8 (eight subjects) and 129 Xe (six subjects) at 1.5T. T 2 ∗ mapping with 19 F-C3 F8 was performed at 1.5T (at FRC and TLC) for 8 subjects and at 3T (at TLC for seven subjects). RESULTS At both FRC and TLC, the 19 F-C3 F8 ADC was smaller than the free diffusion coefficient demonstrating airway microstructural diffusion restriction. From FRC to TLC, the mean ADC significantly increased from 1.56 mm2 /s to 1.83 mm2 /s (P = .0017) for 19 F-C3 F8, and from 2.49 mm2 /s to 3.38 mm2 /s (P = .0015) for 129 Xe. The posterior-to-anterior gradient in ADC for FRC versus TLC in the superior half of the lungs was measured as 0.0308 mm2 /s per cm versus 0.0168 mm2 /s per cm for 19 F-C3 F8 and 0.0871 mm2 /s per cm versus 0.0326 mm2 /s per cm for 129 Xe. A consistent distribution of 19 F-C3 F8 T 2 ∗ values was observed in the lungs, with low values observed near the diaphragm and large pulmonary vessels. The mean T 2 ∗ across volunteers was 4.48 ms at FRC and 5.33 ms at TLC for 1.5T, and 3.78 ms at TLC for 3T. CONCLUSION In this feasibility study, values of physiologically relevant parameters of lung microstructure measurable by MRI ( T 2 ∗ , and ADC) were established for C3 F8 in vivo lung imaging in healthy volunteers.
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Affiliation(s)
- Adam Maunder
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Ho-Fung Chan
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Paul J C Hughes
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Guillhem Collier
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Graham Norquay
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Oliver Rodgers
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Peter Thelwall
- Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Fraser Robb
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom.,GE Healthcare, Aurora, Ohio, USA
| | - Madhwesha Rao
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Jim M Wild
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
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11
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Xiao S, Deng H, Duan C, Xie J, Li H, Sun X, Ye C, Zhou X. Highly and Adaptively Undersampling Pattern for Pulmonary Hyperpolarized 129Xe Dynamic MRI. IEEE TRANSACTIONS ON MEDICAL IMAGING 2019; 38:1240-1250. [PMID: 30475715 DOI: 10.1109/tmi.2018.2882209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hyperpolarized (HP) gas (e.g., 3He or 129Xe) dynamic MRI could visualize the lung ventilation process, which provides characteristics regarding lung physiology and pathophysiology. Compressed sensing (CS) is generally used to increase the temporal resolution of such dynamic MRI. Nevertheless, the acceleration factor of CS is constant, which results in difficulties in precisely observing and/or measuring dynamic ventilation process due to bifurcating network structure of the lung. Here, an adaptive strategy is proposed to highly undersample pulmonary HP dynamic k-space data, according to the characteristics of both lung structure and gas motion. After that, a valid reconstruction algorithm is developed to reconstruct dynamic MR images, considering the low-rank, global sparsity, gas-inflow effects, and joint sparsity. Both the simulation and the in vivo results verify that the proposed approach outperforms the state-of-the-art methods both in qualitative and quantitative comparisons. In particular, the proposed method acquires 33 frames within 6.67 s (more than double the temporal resolution of the recently proposed strategy), and achieves high-image quality [the improvements are 29.63%, 3.19%, 2.08%, and 13.03% regarding the mean absolute error (MAE), structural similarity index (SSIM), quality index based on local variance (QILV), and contrast-to-noise ratio (CNR) comparisons]. This provides accurate structural and functional information for early detection of obstructive lung diseases.
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12
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Westcott A, McCormack DG, Parraga G, Ouriadov A. Advanced pulmonary MRI to quantify alveolar and acinar duct abnormalities: Current status and future clinical applications. J Magn Reson Imaging 2019; 50:28-40. [PMID: 30637857 DOI: 10.1002/jmri.26623] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 12/23/2022] Open
Abstract
There are serious clinical gaps in our understanding of chronic lung disease that require novel, sensitive, and noninvasive in vivo measurements of the lung parenchyma to measure disease pathogenesis and progressive changes over time as well as response to treatment. Until recently, our knowledge and appreciation of the tissue changes that accompany lung disease has depended on ex vivo biopsy and concomitant histological and stereological measurements. These measurements have revealed the underlying pathologies that drive lung disease and have provided important observations about airway occlusion, obliteration of the terminal bronchioles and airspace enlargement, or fibrosis and their roles in disease initiation and progression. ex vivo tissue stereology and histology are the established gold standards and, more recently, micro-computed tomography (CT) measurements of ex vivo tissue samples has also been employed to reveal new mechanistic findings about the progression of obstructive lung disease in patients. While these approaches have provided important understandings using ex vivo analysis of excised samples, recently developed hyperpolarized noble gas MRI methods provide an opportunity to noninvasively measure acinar duct and terminal airway dimensions and geometry in vivo, and, without radiation burden. Therefore, in this review we summarize emerging pulmonary MRI morphometry methods that provide noninvasive in vivo measurements of the lung in patients with bronchopulmonary dysplasia and chronic obstructive pulmonary disease, among others. We discuss new findings, future research directions, as well as clinical opportunities to address current gaps in patient care and for testing of new therapies. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:28-40.
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Affiliation(s)
- Andrew Westcott
- Robarts Research Institute, University of Western Ontario, London, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Canada
| | - David G McCormack
- Division of Respirology, Department of Medicine, University of Western Ontario, London, Canada
| | - Grace Parraga
- Robarts Research Institute, University of Western Ontario, London, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Canada.,Division of Respirology, Department of Medicine, University of Western Ontario, London, Canada
| | - Alexei Ouriadov
- Department of Physics and Astronomy, University of Western Ontario, London, Canada
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13
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Westcott A, Capaldi DP, Ouriadov A, McCormack DG, Parraga G. Hyperpolarized 3
He MRI ventilatory apparent diffusion coefficient of alpha-1 antitrypsin deficiency. J Magn Reson Imaging 2018; 49:311-313. [DOI: 10.1002/jmri.26202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 01/20/2023] Open
Affiliation(s)
- Andrew Westcott
- Robarts Research Institute; Western University; London ON Canada
- Department of Medical Biophysics; Western University; London ON Canada
| | - Dante P.I. Capaldi
- Robarts Research Institute; Western University; London ON Canada
- Department of Medical Biophysics; Western University; London ON Canada
| | - Alexei Ouriadov
- Robarts Research Institute; Western University; London ON Canada
| | - David G. McCormack
- Division of Respirology, Department of Medicine; Western University; London ON Canada
| | - Grace Parraga
- Robarts Research Institute; Western University; London ON Canada
- Department of Medical Biophysics; Western University; London ON Canada
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14
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Xiao S, Deng H, Duan C, Xie J, Zhang H, Sun X, Ye C, Zhou X. Considering low-rank, sparse and gas-inflow effects constraints for accelerated pulmonary dynamic hyperpolarized 129Xe MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 290:29-37. [PMID: 29549792 DOI: 10.1016/j.jmr.2018.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/02/2018] [Accepted: 03/05/2018] [Indexed: 06/08/2023]
Abstract
Dynamic hyperpolarized (HP) 129Xe MRI is able to visualize the process of lung ventilation, which potentially provides unique information about lung physiology and pathophysiology. However, the longitudinal magnetization of HP 129Xe is nonrenewable, making it difficult to achieve high image quality while maintaining high temporal-spatial resolution in the pulmonary dynamic MRI. In this paper, we propose a new accelerated dynamic HP 129Xe MRI scheme incorporating the low-rank, sparse and gas-inflow effects (L + S + G) constraints. According to the gas-inflow effects of HP gas during the lung inspiratory process, a variable-flip-angle (VFA) strategy is designed to compensate for the rapid attenuation of the magnetization. After undersampling k-space data, an effective reconstruction algorithm considering the low-rank, sparse and gas-inflow effects constraints is developed to reconstruct dynamic MR images. In this way, the temporal and spatial resolution of dynamic MR images is improved and the artifacts are lessened. Simulation and in vivo experiments implemented on the phantom and healthy volunteers demonstrate that the proposed method is not only feasible and effective to compensate for the decay of the magnetization, but also has a significant improvement compared with the conventional reconstruction algorithms (P-values are less than 0.05). This confirms the superior performance of the proposed designs and their ability to maintain high quality and temporal-spatial resolution.
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Affiliation(s)
- Sa Xiao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - He Deng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Caohui Duan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Junshuai Xie
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Huiting Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Xianping Sun
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Chaohui Ye
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
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15
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Eddy RL, Svenningsen S, McCormack DG, Parraga G. What is the minimal clinically important difference for helium-3 magnetic resonance imaging ventilation defects? Eur Respir J 2018; 51:13993003.00324-2018. [DOI: 10.1183/13993003.00324-2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/03/2018] [Indexed: 11/05/2022]
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16
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Young HM, Guo F, Eddy RL, Maksym G, Parraga G. Oscillometry and pulmonary MRI measurements of ventilation heterogeneity in obstructive lung disease: relationship to quality of life and disease control. J Appl Physiol (1985) 2018. [PMID: 29543132 DOI: 10.1152/japplphysiol.01031.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ventilation heterogeneity is a hallmark finding in obstructive lung disease and may be evaluated using a variety of methods, including multiple-breath gas washout and pulmonary imaging. Such methods provide an opportunity to better understand the relationships between structural and functional abnormalities in the lungs, and their relationships with important clinical outcomes. We measured ventilation heterogeneity and respiratory impedance in 100 subjects [50 patients with asthma, 22 ex-smokers, and 28 patients with chronic obstructive pulmonary disease (COPD)] using oscillometry and hyperpolarized 3He magnetic resonance imaging (MRI) and determined their relationships with quality of life scores and disease control/exacerbations. We also coregistered MRI ventilation maps to a computational airway tree model to generate patient-specific respiratory impedance predictions for comparison with experimental measurements. In COPD and asthma patients, respectively, forced oscillation technique (FOT)-derived peripheral resistance (5-19 Hz) and MRI ventilation defect percentage (VDP) were significantly related to quality of life (FOT: COPD ρ = 0.4, P = 0.004; asthma ρ = -0.3, P = 0.04; VDP: COPD ρ = 0.6, P = 0.003; asthma ρ = -0.3, P = 0.04). Patients with poorly controlled asthma (Asthmatic Control Questionnaire >2) had significantly increased resistance (5 Hz: P = 0.01; 5-19 Hz: P = 0.006) and reactance (5 Hz: P = 0.03). FOT-derived peripheral resistance (5-19 Hz) was significantly related to VDP in patients with asthma and COPD patients (asthma: ρ = 0.5, P < 0.001; COPD: ρ = 0.5, P = 0.01), whereas total respiratory impedance was related to VDP only in patients with asthma (resistance 5 Hz: ρ = 0.3, P = 0.02; reactance 5 Hz: ρ = -0.5, P < 0.001). Model-predicted and FOT-measured reactance (5 Hz) were correlated in patients with asthma (ρ = 0.5, P = 0.001), whereas in COPD patients, model-predicted and FOT-measured resistance (5-19 Hz) were correlated (ρ = 0.5, P = 0.004). In summary, in patients with asthma and COPD patients, we observed significant, independent relationships for FOT-measured impedance and MRI ventilation heterogeneity measurements with one another and with quality of life scores. NEW & NOTEWORTHY In 100 patients, including patients with asthma and ex-smokers, 3He MRI ventilation heterogeneity and respiratory system impedance were correlated and both were independently related to quality of life scores and asthma control. These findings demonstrated the critical relationships between respiratory system impedance and ventilation heterogeneity and their role in determining quality of life and disease control. These observations underscore the dominant role that abnormalities in the lung periphery play in ventilation heterogeneity that results in patients' symptoms.
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Affiliation(s)
- Heather M Young
- Robarts Research Institute, Western University , London, Ontario , Canada.,Department of Medical Biophysics, Western University , London, Ontario , Canada
| | - Fumin Guo
- Robarts Research Institute, Western University , London, Ontario , Canada.,Graduate Program in Biomedical Engineering, Western University , London, Ontario , Canada
| | - Rachel L Eddy
- Robarts Research Institute, Western University , London, Ontario , Canada.,Department of Medical Biophysics, Western University , London, Ontario , Canada
| | - Geoffrey Maksym
- School of Biomedical Engineering, Dalhousie University , Halifax, Nova Scotia , Canada
| | - Grace Parraga
- Robarts Research Institute, Western University , London, Ontario , Canada.,Department of Medical Biophysics, Western University , London, Ontario , Canada.,Graduate Program in Biomedical Engineering, Western University , London, Ontario , Canada
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17
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Abstract
This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.
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Affiliation(s)
- T. R. Gentile
- National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - P. J. Nacher
- Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, UPMC-Sorbonne Universités, Collège de France, Paris, France
| | - B. Saam
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - T. G. Walker
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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18
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Fishman EF, Quirk JD, Sweet SC, Woods JC, Gierada DS, Conradi MS, Siegel MJ, Yablonskiy DA. What makes a good pediatric transplant lung: Insights from in vivo lung morphometry with hyperpolarized 3 He magnetic resonance imaging. Pediatr Transplant 2017; 21:10.1111/petr.12886. [PMID: 28120553 PMCID: PMC5378594 DOI: 10.1111/petr.12886] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/19/2016] [Indexed: 11/26/2022]
Abstract
Obtaining information on transplanted lung microstructure is an important part of the current care for monitoring transplant recipients. However, until now this information was only available from invasive lung biopsy. The objective of this study was to evaluate the use of an innovative non-invasive technique, in vivo lung morphometry with hyperpolarized ³He MRI-to characterize lung microstructure in the pediatric lung transplant population. This technique yields quantitative measurements of acinar airways' (alveolar ducts and sacs) parameters, such as acinar airway radii and alveolar depth. Six pediatric lung transplant recipients with cystic fibrosis underwent in vivo lung morphometry MRI, pulmonary function testing, and quantitative CT. We found a strong correlation between lung lifespan and alveolar depth-patients with more shallow alveoli were likely to have a negative outcome sooner than those with larger alveolar depth. Combining morphometric results with CT, we also determined mean alveolar wall thickness and found substantial increases in this parameter in some patients that negatively correlated with DLCO. In vivo lung morphometry uniquely provides previously unavailable information on lung microstructure that may be predictive of a negative outcome and has a potential to aid in lung selection for transplantation.
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Affiliation(s)
- Emily F. Fishman
- Department of Pediatrics, Washington University, St. Louis, MO, USA
| | - James D. Quirk
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, USA
| | - Stuart C. Sweet
- Department of Pediatrics, Washington University, St. Louis, MO, USA
| | - Jason C. Woods
- Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA,Department of Physics, Washington University, St. Louis, MO, USA
| | - David S. Gierada
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, USA
| | - Mark S. Conradi
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, USA,Department of Physics, Washington University, St. Louis, MO, USA
| | - Marilyn J. Siegel
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, USA
| | - Dmitriy A. Yablonskiy
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, USA,Corresponding Author: Dmitriy A. Yablonskiy, Ph.D., Mallinckrodt Institute of Radiology, Washington University, 4525 Scott Avenue, Campus Box 8227, St. Louis MO, 63110, , Tel.: +1(314) 362-1815, Fax: +1(314) 362-0526
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19
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Adamson EB, Ludwig KD, Mummy DG, Fain SB. Magnetic resonance imaging with hyperpolarized agents: methods and applications. Phys Med Biol 2017; 62:R81-R123. [PMID: 28384123 DOI: 10.1088/1361-6560/aa6be8] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In the past decade, hyperpolarized (HP) contrast agents have been under active development for MRI applications to address the twin challenges of functional and quantitative imaging. Both HP helium (3He) and xenon (129Xe) gases have reached the stage where they are under study in clinical research. HP 129Xe, in particular, is poised for larger scale clinical research to investigate asthma, chronic obstructive pulmonary disease, and fibrotic lung diseases. With advances in polarizer technology and unique capabilities for imaging of 129Xe gas exchange into lung tissue and blood, HP 129Xe MRI is attracting new attention. In parallel, HP 13C and 15N MRI methods have steadily advanced in a wide range of pre-clinical research applications for imaging metabolism in various cancers and cardiac disease. The HP [1-13C] pyruvate MRI technique, in particular, has undergone phase I trials in prostate cancer and is poised for investigational new drug trials at multiple institutions in cancer and cardiac applications. This review treats the methodology behind both HP gases and HP 13C and 15N liquid state agents. Gas and liquid phase HP agents share similar technologies for achieving non-equilibrium polarization outside the field of the MRI scanner, strategies for image data acquisition, and translational challenges in moving from pre-clinical to clinical research. To cover the wide array of methods and applications, this review is organized by numerical section into (1) a brief introduction, (2) the physical and biological properties of the most common polarized agents with a brief summary of applications and methods of polarization, (3) methods for image acquisition and reconstruction specific to improving data acquisition efficiency for HP MRI, (4) the main physical properties that enable unique measures of physiology or metabolic pathways, followed by a more detailed review of the literature describing the use of HP agents to study: (5) metabolic pathways in cancer and cardiac disease and (6) lung function in both pre-clinical and clinical research studies, concluding with (7) some future directions and challenges, and (8) an overall summary.
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Affiliation(s)
- Erin B Adamson
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States of America
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20
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Yablonskiy DA, Sukstanskii AL, Quirk JD. Diffusion lung imaging with hyperpolarized gas MRI. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3448. [PMID: 26676342 PMCID: PMC4911335 DOI: 10.1002/nbm.3448] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/20/2015] [Accepted: 10/22/2015] [Indexed: 05/28/2023]
Abstract
Lung imaging using conventional 1 H MRI presents great challenges because of the low density of lung tissue, lung motion and very fast lung tissue transverse relaxation (typical T2 * is about 1-2 ms). MRI with hyperpolarized gases (3 He and 129 Xe) provides a valuable alternative because of the very strong signal originating from inhaled gas residing in the lung airspaces and relatively slow gas T2 * relaxation (typical T2 * is about 20-30 ms). However, in vivo human experiments should be performed very rapidly - usually during a single breath-hold. In this review, we describe the recent developments in diffusion lung MRI with hyperpolarized gases. We show that a combination of the results of modeling of gas diffusion in lung airspaces and diffusion measurements with variable diffusion-sensitizing gradients allows the extraction of quantitative information on the lung microstructure at the alveolar level. From an MRI scan of less than 15 s, this approach, called in vivo lung morphometry, allows the provision of quantitative values and spatial distributions of the same physiological parameters as measured by means of 'standard' invasive stereology (mean linear intercept, surface-to-volume ratio, density of alveoli, etc.). In addition, the approach makes it possible to evaluate some advanced Weibel parameters characterizing lung microstructure: average radii of alveolar sacs and ducts, as well as the depth of their alveolar sleeves. Such measurements, providing in vivo information on the integrity of pulmonary acinar airways and their changes in different diseases, are of great importance and interest to a broad range of physiologists and clinicians. We also discuss a new type of experiment based on the in vivo lung morphometry technique combined with quantitative computed tomography measurements, as well as with gradient echo MRI measurements of hyperpolarized gas transverse relaxation in the lung airspaces. Such experiments provide additional information on the blood vessel volume fraction, specific gas volume and length of the acinar airways, and allow the evaluation of lung parenchymal and non-parenchymal tissue. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
| | | | - James D Quirk
- Department of Radiology, Washington University, St. Louis, MO, USA
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21
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Balbinot F, da Costa Batista Guedes Á, Nascimento DZ, Zampieri JF, Alves GRT, Marchiori E, Rubin AS, Hochhegger B. Advances in Imaging and Automated Quantification of Pulmonary Diseases in Non-neoplastic Diseases. Lung 2016; 194:871-879. [PMID: 27663257 DOI: 10.1007/s00408-016-9940-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/03/2016] [Indexed: 10/21/2022]
Abstract
Histological examination has always been the gold standard for the detection and quantification of lung remodeling. However, this method has some limitations regarding the invasiveness of tissue acquisition. Quantitative imaging methods enable the acquisition of valuable information on lung structure and function without the removal of tissue from the body; thus, they are useful for disease identification and follow-up. This article reviews the various quantitative imaging modalities used currently for the non-invasive study of chronic obstructive pulmonary disease, asthma, and interstitial lung diseases. Some promising computer-aided diagnosis methods are also described.
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Affiliation(s)
- Fernanda Balbinot
- Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil. .,, Rua Coronel Vicente, 451, Centro, Porto Alegre, RS, 90030041, Brazil. .,Irmandade Santa Casa de Misericórdia de Porto Alegre, LABIMED - Laboratório de Pesquisas em Imagens Médicas, Rua Prof. Annes Dias, 28, Centro, Porto Alegre, RS, 90020090, Brazil.
| | - Álvaro da Costa Batista Guedes
- Irmandade Santa Casa de Misericórdia de Porto Alegre, LABIMED - Laboratório de Pesquisas em Imagens Médicas, Rua Prof. Annes Dias, 28, Centro, Porto Alegre, RS, 90020090, Brazil
| | - Douglas Zaione Nascimento
- Irmandade Santa Casa de Misericórdia de Porto Alegre, LABIMED - Laboratório de Pesquisas em Imagens Médicas, Rua Prof. Annes Dias, 28, Centro, Porto Alegre, RS, 90020090, Brazil
| | - Juliana Fischman Zampieri
- Irmandade Santa Casa de Misericórdia de Porto Alegre, LABIMED - Laboratório de Pesquisas em Imagens Médicas, Rua Prof. Annes Dias, 28, Centro, Porto Alegre, RS, 90020090, Brazil
| | | | - Edson Marchiori
- Federal University of Rio de Janeiro, Rua Thomaz Cameron, 43, Valparaíso, Petrópolis, RJ, 25685120, Brazil
| | - Adalberto Sperb Rubin
- Irmandade Santa Casa de Misericórdia de Porto Alegre, LABIMED - Laboratório de Pesquisas em Imagens Médicas, Rua Prof. Annes Dias, 28, Centro, Porto Alegre, RS, 90020090, Brazil
| | - Bruno Hochhegger
- Irmandade Santa Casa de Misericórdia de Porto Alegre, LABIMED - Laboratório de Pesquisas em Imagens Médicas, Rua Prof. Annes Dias, 28, Centro, Porto Alegre, RS, 90020090, Brazil
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22
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Hoffman EA, Lynch DA, Barr RG, van Beek EJR, Parraga G. Pulmonary CT and MRI phenotypes that help explain chronic pulmonary obstruction disease pathophysiology and outcomes. J Magn Reson Imaging 2016; 43:544-57. [PMID: 26199216 PMCID: PMC5207206 DOI: 10.1002/jmri.25010] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022] Open
Abstract
Pulmonary x-ray computed tomographic (CT) and magnetic resonance imaging (MRI) research and development has been motivated, in part, by the quest to subphenotype common chronic lung diseases such as chronic obstructive pulmonary disease (COPD). For thoracic CT and MRI, the main COPD research tools, disease biomarkers are being validated that go beyond anatomy and structure to include pulmonary functional measurements such as regional ventilation, perfusion, and inflammation. In addition, there has also been a drive to improve spatial and contrast resolution while at the same time reducing or eliminating radiation exposure. Therefore, this review focuses on our evolving understanding of patient-relevant and clinically important COPD endpoints and how current and emerging MRI and CT tools and measurements may be exploited for their identification, quantification, and utilization. Since reviews of the imaging physics of pulmonary CT and MRI and reviews of other COPD imaging methods were previously published and well-summarized, we focus on the current clinical challenges in COPD and the potential of newly emerging MR and CT imaging measurements to address them. Here we summarize MRI and CT imaging methods and their clinical translation for generating reproducible and sensitive measurements of COPD related to pulmonary ventilation and perfusion as well as parenchyma morphology. The key clinical problems in COPD provide an important framework in which pulmonary imaging needs to rapidly move in order to address the staggering burden, costs, as well as the mortality and morbidity associated with COPD.
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Affiliation(s)
- Eric A Hoffman
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - David A Lynch
- Department of Radiology, National Jewish Health Center, Denver, Colorado, USA
| | - R Graham Barr
- Division of General Medicine, Division of Pulmonary, Allergy and Critical Care, Department of Medicine, Columbia University Medical Center, New York, New York, USA
- Department of Epidemiology, Columbia University Medical Center, New York, New York, USA
| | - Edwin J R van Beek
- Clinical Research Imaging Centre, Queen's Medical Research Institute, University of Edinburgh, Scotland, UK
| | - Grace Parraga
- Robarts Research Institute, University of Western Ontario, London, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Canada
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23
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Kruger SJ, Nagle SK, Couch MJ, Ohno Y, Albert M, Fain SB. Functional imaging of the lungs with gas agents. J Magn Reson Imaging 2016; 43:295-315. [PMID: 26218920 PMCID: PMC4733870 DOI: 10.1002/jmri.25002] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 06/26/2015] [Indexed: 12/22/2022] Open
Abstract
This review focuses on the state-of-the-art of the three major classes of gas contrast agents used in magnetic resonance imaging (MRI)-hyperpolarized (HP) gas, molecular oxygen, and fluorinated gas--and their application to clinical pulmonary research. During the past several years there has been accelerated development of pulmonary MRI. This has been driven in part by concerns regarding ionizing radiation using multidetector computed tomography (CT). However, MRI also offers capabilities for fast multispectral and functional imaging using gas agents that are not technically feasible with CT. Recent improvements in gradient performance and radial acquisition methods using ultrashort echo time (UTE) have contributed to advances in these functional pulmonary MRI techniques. The relative strengths and weaknesses of the main functional imaging methods and gas agents are compared and applications to measures of ventilation, diffusion, and gas exchange are presented. Functional lung MRI methods using these gas agents are improving our understanding of a wide range of chronic lung diseases, including chronic obstructive pulmonary disease, asthma, and cystic fibrosis in both adults and children.
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Affiliation(s)
- Stanley J. Kruger
- Department of Medical Physics, University of Wisconsin – Madison, WI, U.S.A
| | - Scott K. Nagle
- Department of Medical Physics, University of Wisconsin – Madison, WI, U.S.A
- Department of Radiology, University of Wisconsin – Madison, WI, U.S.A
- Department of Pediatrics, University of Wisconsin – Madison, WI, U.S.A
| | - Marcus J. Couch
- Thunder Bay Regional Research Institute, Thunder Bay, ON, Canada
- Biotechnology Program, Lakehead University, Thunder Bay, ON, Canada
| | - Yoshiharu Ohno
- Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Mitchell Albert
- Thunder Bay Regional Research Institute, Thunder Bay, ON, Canada
- Department of Chemistry, Lakehead University, Thunder Bay, ON, Canada
| | - Sean B. Fain
- Department of Medical Physics, University of Wisconsin – Madison, WI, U.S.A
- Department of Radiology, University of Wisconsin – Madison, WI, U.S.A
- Department of Biomedical Engineering, University of Wisconsin – Madison, WI, U.S.A
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24
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Yablonskiy DA, Sukstanskii AL, Quirk JD, Woods JC, Conradi MS. Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results. Magn Reson Med 2016; 71:486-505. [PMID: 23554008 DOI: 10.1002/mrm.24729] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The introduction of hyperpolarized gases ((3)He and (129)Xe) has opened the door to applications for which gaseous agents are uniquely suited-lung MRI. One of the pulmonary applications, diffusion MRI, relies on measuring Brownian motion of inhaled hyperpolarized gas atoms diffusing in lung airspaces. In this article we provide an overview of the theoretical ideas behind hyperpolarized gas diffusion MRI and the results obtained over the decade-long research. We describe a simple technique based on measuring gas apparent diffusion coefficient (ADC) and an advanced technique, in vivo lung morphometry, that quantifies lung microstructure both in terms of Weibel parameters (acinar airways radii and alveolar depth) and standard metrics (mean linear intercept, surface-to-volume ratio, and alveolar density) that are widely used by lung researchers but were previously available only from invasive lung biopsy. This technique has the ability to provide unique three-dimensional tomographic information on lung microstructure from a less than 15 s MRI scan with results that are in good agreement with direct histological measurements. These safe and sensitive diffusion measurements improve our understanding of lung structure and functioning in health and disease, providing a platform for monitoring the efficacy of therapeutic interventions in clinical trials.
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25
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Abstract
Imaging has played a vital role in the clinical assessment of bronchopulmonary dysplasia (BPD) since its first recognition. In this review, how chest radiograph, computerized tomography (CT), nuclear medicine, and MRI have contributed to the understanding of BPD pathology and how emerging advancements in these methods, including low-dose and quantitative CT, sophisticated proton and hyperpolarized-gas MRI, influence the future of BPD imaging are discussed.
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Affiliation(s)
- Laura L Walkup
- Division of Pulmonary Medicine, Department of Radiology, Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, MC 5033, Cincinnati, OH 42229, USA
| | - Jason C Woods
- Division of Pulmonary Medicine, Department of Radiology, Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, MC 5033, Cincinnati, OH 42229, USA.
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26
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Kirby M, Ohtani K, Nickens T, Lisbona RML, Lee AMD, Shaipanich T, Lane P, MacAulay C, Lam S, Coxson HO. Reproducibility of optical coherence tomography airway imaging. BIOMEDICAL OPTICS EXPRESS 2015; 6:4365-77. [PMID: 26601002 PMCID: PMC4646546 DOI: 10.1364/boe.6.004365] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 09/23/2015] [Accepted: 09/30/2015] [Indexed: 05/23/2023]
Abstract
Optical coherence tomography (OCT) is a promising imaging technique to evaluate small airway remodeling. However, the short-term insertion-reinsertion reproducibility of OCT for evaluating the same bronchial pathway has yet to be established. We evaluated 74 OCT data sets from 38 current or former smokers twice within a single imaging session. Although the overall insertion-reinsertion airway wall thickness (WT) measurement coefficient of variation (CV) was moderate at 12%, much of the variability between repeat imaging was attributed to the observer; CV for repeated measurements of the same airway (intra-observer CV) was 9%. Therefore, reproducibility may be improved by introduction of automated analysis approaches suggesting that OCT has potential to be an in-vivo method for evaluating airway remodeling in future longitudinal and intervention studies.
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Affiliation(s)
- Miranda Kirby
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, British Columbia, Canada
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Keishi Ohtani
- Department of Surgery, Tokyo Medical University, Tokyo, Japan
| | - Taylor Nickens
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Rosa Maria Lopez Lisbona
- Department of Respirology, Bellvitge University Hospital, l’Hospitalet de Llobregat, Barcelona, Spain
| | - Anthony M. D. Lee
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
| | - Tawimas Shaipanich
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
| | - Pierre Lane
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
| | - Calum MacAulay
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
| | - Stephen Lam
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Harvey O. Coxson
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, British Columbia, Canada
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
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27
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Ouriadov A, Fox M, Hegarty E, Parraga G, Wong E, Santyr GE. Early stage radiation-induced lung injury detected using hyperpolarized (129) Xe Morphometry: Proof-of-concept demonstration in a rat model. Magn Reson Med 2015; 75:2421-31. [PMID: 26154889 DOI: 10.1002/mrm.25825] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 05/27/2015] [Accepted: 06/08/2015] [Indexed: 11/08/2022]
Abstract
PURPOSE Radiation-induced lung injury (RILI) is still the major dose-limiting toxicity related to lung cancer radiation therapy, and it is difficult to predict and detect patients who are at early risk of severe pneumonitis and fibrosis. The goal of this proof-of-concept preclinical demonstration was to investigate the potential of hyperpolarized (129) Xe diffusion-weighted MRI to detect the lung morphological changes associated with early stage RILI. METHODS Hyperpolarized (129) Xe MRI was performed using eight different diffusion sensitizations (0.0-115 s/cm(2) ) in a small group of control rats (n = 4) and rats 2 wk after radiation exposure (n = 5). The diffusion-weighted images were used to obtain morphological estimates of the pulmonary parenchyma including external radius (R), internal radius (r), alveolar sleeve depth (h), and mean airspace chord length (Lm ). The histological mean linear intercept (MLI) were obtained for five control and five irradiated animals. RESULTS Mean R, r, and Lm were both significantly different (P < 0.02) in the irradiated rats (74 ± 17 µm, 43 ± 12 µm, and 54 ± 17 µm, respectively) compared with the control rats (100 ± 12 µm, 67 ± 10 µm, and 79 ± 12 µm, respectively). Changes in measured Lm values were consistent with changes in MLI values observed by histology. CONCLUSIONS Hyperpolarized (129) Xe MRI provides a way to detect and measure regional microanatomical changes in lung parenchyma in a preclinical model of RILI. Magn Reson Med 75:2421-2431, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexei Ouriadov
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada
| | - Matthew Fox
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.,Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Elaine Hegarty
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada
| | - Grace Parraga
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.,Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Eugene Wong
- Department of Medical Biophysics, Western University, London, Ontario, Canada.,Department of Physics and Astronomy, Western University, London, Ontario, Canada
| | - Giles E Santyr
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.,Department of Medical Biophysics, Western University, London, Ontario, Canada.,Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
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28
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Kirby M, Ohtani K, Lopez Lisbona RM, Lee AMD, Zhang W, Lane P, Varfolomeva N, Hui L, Ionescu D, Coxson HO, MacAulay C, FitzGerald JM, Lam S. Bronchial thermoplasty in asthma: 2-year follow-up using optical coherence tomography. Eur Respir J 2015; 46:859-62. [PMID: 26022958 DOI: 10.1183/09031936.00016815] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/10/2015] [Indexed: 11/05/2022]
Affiliation(s)
- Miranda Kirby
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul's Hospital, Vancouver, BC, Canada
| | - Keishi Ohtani
- Department of Surgery, Tokyo Medical University, Tokyo, Japan Imaging Unit, Integrative Oncology Department, British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - Rosa Maria Lopez Lisbona
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Research Centre, Vancouver, BC, Canada Department of Respirology, Bellvitge University Hospital, Hospitalet de Llobregat, Barcelona, Spain
| | - Anthony M D Lee
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - Wei Zhang
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Research Centre, Vancouver, BC, Canada Department of Respiratory and Critical Care Medicine, Peking University First Hospital, Beijing, China
| | - Pierre Lane
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - Nina Varfolomeva
- Institute for Heart and Lung Health, University of British Columbia and Vancouver General Hospital, Vancouver, BC, Canada
| | - Linda Hui
- Institute for Heart and Lung Health, University of British Columbia and Vancouver General Hospital, Vancouver, BC, Canada
| | - Diana Ionescu
- Department of Pathology, British Columbia Cancer Agency and the University of British Columbia, Vancouver, BC, Canada
| | - Harvey O Coxson
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul's Hospital, Vancouver, BC, Canada
| | - Calum MacAulay
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Research Centre, Vancouver, BC, Canada
| | - J Mark FitzGerald
- Institute for Heart and Lung Health, University of British Columbia and Vancouver General Hospital, Vancouver, BC, Canada
| | - Stephen Lam
- Imaging Unit, Integrative Oncology Department, British Columbia Cancer Research Centre, Vancouver, BC, Canada Institute for Heart and Lung Health, University of British Columbia and Vancouver General Hospital, Vancouver, BC, Canada
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29
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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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30
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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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31
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McNulty W, Usmani OS. Techniques of assessing small airways dysfunction. Eur Clin Respir J 2014; 1:25898. [PMID: 26557240 PMCID: PMC4629724 DOI: 10.3402/ecrj.v1.25898] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 09/11/2014] [Indexed: 11/17/2022] Open
Abstract
The small airways are defined as those less than 2 mm in diameter. They are a major site of pathology in many lung diseases, not least chronic obstructive pulmonary disease (COPD) and asthma. The small airways are frequently involved early in the course of these diseases, with significant pathology demonstrable often before the onset of symptoms or changes in spirometry and imaging. Despite their importance, they have proven relatively difficult to study. This is in part due to their relative inaccessibility to biopsy and their small size which makes their imaging difficult. Traditional lung function tests may only become abnormal once there is a significant burden of disease within them. This has led to the term 'the quiet zone' of the lung. In recent years, more specialised tests have been developed which may detect these changes earlier, perhaps offering the possibility of earlier diagnosis and intervention. These tests are now moving from the realms of clinical research laboratories into routine clinical practice and are increasingly useful in the diagnosis and monitoring of respiratory diseases. This article gives an overview of small airways physiology and some of the routine and more advanced tests of airway function.
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Affiliation(s)
- William McNulty
- National Heart and lung Institute, Imperial College London and Royal Brompton Hospital, London, UK
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32
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Kirby M, Ouriadov A, Svenningsen S, Owrangi A, Wheatley A, Etemad‐Rezai R, Santyr GE, McCormack DG, Parraga G. Hyperpolarized 3He and 129Xe magnetic resonance imaging apparent diffusion coefficients: physiological relevance in older never- and ex-smokers. Physiol Rep 2014; 2:e12068. [PMID: 25347853 PMCID: PMC4187551 DOI: 10.14814/phy2.12068] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 05/30/2014] [Accepted: 06/04/2014] [Indexed: 11/24/2022] Open
Abstract
Noble gas pulmonary magnetic resonance imaging (MRI) is transitioning away from (3)He to (129)Xe gas, but the physiological/clinical relevance of (129)Xe apparent diffusion coefficient (ADC) parenchyma measurements is not well understood. Therefore, our objective was to generate (129)Xe MRI ADC for comparison with (3)He ADC and with well-established measurements of alveolar structure and function in older never-smokers and ex-smokers with chronic obstructive pulmonary disease (COPD). In four never-smokers and 10 COPD ex-smokers, (3)He (b = 1.6 sec/cm(2)) and (129)Xe (b = 12, 20, and 30 sec/cm(2)) ADC, computed tomography (CT) density-threshold measurements, and the diffusing capacity for carbon monoxide (DLCO) were measured. To understand regional differences, the anterior-posterior (APG) and superior-inferior (∆SI) ADC differences were evaluated. Compared to never-smokers, COPD ex-smokers showed greater (3)He ADC (P = 0.006), (129)Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.006), but not for ADCb30 (P > 0.05). Never-smokers and COPD ex-smokers had significantly different APG for (3)He ADC (P = 0.02), (129)Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.01), but not for ADCb30 (P > 0.05). ∆SI for never- and ex-smokers was significantly different for (3)He ADC (P = 0.046), but not for (129)Xe ADC (P > 0.05). There were strong correlations for DLCO with (3)He ADC and (129)Xe ADCb12 (both r = -0.95, P < 0.05); in a multivariate model (129)Xe ADCb12 was the only significant predictor of DLCO (P = 0.049). For COPD ex-smokers, CT relative area <-950 HU (RA950) correlated with (3)He ADC (r = 0.90, P = 0.008) and (129)Xe ADCb12 (r = 0.85, P = 0.03). In conclusion, while (129)Xe ADCb30 may be appropriate for evaluating subclinical or mild emphysema, in this small group of never-smokers and ex-smokers with moderate-to-severe emphysema, (129)Xe ADCb12 provided a physiologically appropriate estimate of gas exchange abnormalities and alveolar microstructure.
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Affiliation(s)
- Miranda Kirby
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Alexei Ouriadov
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Sarah Svenningsen
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Amir Owrangi
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada
| | - Andrew Wheatley
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Roya Etemad‐Rezai
- Department of Medical Imaging, The University of Western Ontario, London, Ontario, Canada
| | - Giles E. Santyr
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - David G. McCormack
- Division of Respirology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada
| | - Grace Parraga
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada
- Department of Medical Imaging, The University of Western Ontario, London, Ontario, Canada
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33
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Lee AMD, Kirby M, Ohtani K, Candido T, Shalansky R, MacAulay C, English J, Finley R, Lam S, Coxson HO, Lane P. Validation of airway wall measurements by optical coherence tomography in porcine airways. PLoS One 2014; 9:e100145. [PMID: 24949633 PMCID: PMC4064993 DOI: 10.1371/journal.pone.0100145] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 05/22/2014] [Indexed: 11/19/2022] Open
Abstract
Examining and quantifying changes in airway morphology is critical for studying longitudinal pathogenesis and interventions in diseases such as chronic obstructive pulmonary disease and asthma. Here we present fiber-optic optical coherence tomography (OCT) as a nondestructive technique to precisely and accurately measure the 2-dimensional cross-sectional areas of airway wall substructure divided into the mucosa (WAmuc), submucosa (WAsub), cartilage (WAcart), and the airway total wall area (WAt). Porcine lung airway specimens were dissected from freshly resected lung lobes (N = 10). Three-dimensional OCT imaging using a fiber-optic rotary-pullback probe was performed immediately on airways greater than 0.9 mm in diameter on the fresh airway specimens and subsequently on the same specimens post-formalin-fixation. The fixed specimens were serially sectioned and stained with H&E. OCT images carefully matched to selected sections stained with Movat's pentachrome demonstrated that OCT effectively identifies airway epithelium, lamina propria, and cartilage. Selected H&E sections were digitally scanned and airway total wall areas were measured. Traced measurements of WAmuc, WAsub, WAcart, and WAt from OCT images of fresh specimens by two independent observers found there were no significant differences (p>0.05) between the observer's measurements. The same wall area measurements from OCT images of formalin-fixed specimens found no significant differences for WAsub, WAcart and WAt, and a small but significant difference for WAmuc. Bland-Altman analysis indicated there were negligible biases between the observers for OCT wall area measurements in both fresh and formalin-fixed specimens. Bland-Altman analysis also indicated there was negligible bias between histology and OCT wall area measurements for both fresh and formalin-fixed specimens. We believe this study sets the groundwork for quantitatively monitoring pathogenesis and interventions in the airways using OCT.
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Affiliation(s)
- Anthony M. D. Lee
- Department of Integrative Oncology - Imaging Unit, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
- * E-mail:
| | - Miranda Kirby
- Department of Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Keishi Ohtani
- Department of Integrative Oncology - Imaging Unit, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
| | - Tara Candido
- Department of Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Rebecca Shalansky
- Department of Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Calum MacAulay
- Department of Integrative Oncology - Imaging Unit, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
| | - John English
- Department of Pathology, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Richard Finley
- Department of Surgery, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Stephen Lam
- Department of Integrative Oncology - Imaging Unit, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
| | - Harvey O. Coxson
- Department of Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada
| | - Pierre Lane
- Department of Integrative Oncology - Imaging Unit, British Columbia Cancer Agency Research Centre, Vancouver, British Columbia, Canada
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Owrangi AM, Wang JX, Wheatley A, McCormack DG, Parraga G. Quantitative 1H and hyperpolarized 3He magnetic resonance imaging: Comparison in chronic obstructive pulmonary disease and healthy never-smokers. Eur J Radiol 2014; 83:64-72. [DOI: 10.1016/j.ejrad.2012.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 02/27/2012] [Indexed: 10/28/2022]
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Kirby M, Parraga G. Pulmonary functional imaging using hyperpolarized noble gas MRI: six years of start-up experience at a single site. Acad Radiol 2013; 20:1344-56. [PMID: 24119346 DOI: 10.1016/j.acra.2013.02.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 01/31/2013] [Accepted: 02/01/2013] [Indexed: 12/01/2022]
Abstract
RATIONALE AND OBJECTIVES In this review, we summarize our experience evaluating pulmonary function in 330 different subjects using hyperpolarized noble gas magnetic resonance imaging (MRI) after enrollment and screening of >1100 subjects with and without respiratory disease during the period February 1, 2006, through November 1, 2012. MATERIALS AND METHODS We discuss the feasibility of hyperpolarized gas MRI research in a small nonhospital research unit and provide an overview of our experience since we initiated patient-based studies. We also discuss the importance of infrastructure support, collaboration, research trainees, and a large and willing patient population that helped to advance the research and technological deliverables. A summary of patient safety and tolerability, key feasibility, and research milestones is provided, as well as a roadmap for future studies. RESULTS Hyperpolarized (3)He and (129)Xe gas MRI is feasible at smaller centers without significant human resources for large and small longitudinal studies by virtue of its excellent patient safety and tolerability, the speed with which images can be acquired and quantitatively analyzed and the high spatial-temporal dynamics of the method that allows for acute and chronic therapy studies. CONCLUSIONS The hyperpolarized noble gas MRI community's highly collaborative efforts and motivation to further the development and application of this tool has resulted in a moment-of-opportunity to translate the method clinically to provide an improved understanding of pulmonary disease. There are, as well, new and unprecedented opportunities for the evaluation of disease progression and to help develop the new treatments and interventions critically required for chronic pulmonary disease.
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Affiliation(s)
- Miranda Kirby
- Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada, N6A 5K8; Department of Medical Biophysics, London, Canada
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Thien F. Measuring and imaging small airways dysfunction in asthma. Asia Pac Allergy 2013; 3:224-30. [PMID: 24260727 PMCID: PMC3826607 DOI: 10.5415/apallergy.2013.3.4.224] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/04/2013] [Indexed: 11/26/2022] Open
Abstract
Asthma is a chronic inflammatory disorder of the airways causing typical symptoms, and the diagnosis is supported by evidence of airflow obstruction which is variable, reversible or inducible. However, standard assessment of lung function with spirometry does not measure dysfunction in small airways which are < 2 mm in diameter towards the periphery of the lung. These airways make only a small contribution to airway resistance under normal circumstances. Nevertheless, there is mounting evidence that pathology and dysfunction in these small airways are implicated in the pathogenesis and natural history of asthma. Using forced oscillation and the multibreath nitrogen washout techniques, uneven ventilation (ventilation heterogeneity) due to small airways dysfunction has been shown to be an important marker of asthma disease activity, even in the absence of abnormalities in standard spirometric measurements. Recent advances in imaging research, particularly with hyperpolarised gas magnetic resonance imaging, have also given insights into the significance and dynamic nature of ventilation heterogeneity in asthma. The challenge is to integrate these new physiological and imaging insights to further our understanding of asthma and facilitate potential new treatments.
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Affiliation(s)
- Francis Thien
- Department of Respiratory Medicine, Eastern Health and Monash University, Box Hill Hospital, Box Hill, VIC 3128, Australia
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Abstract
A better understanding of the anatomic structure and physiological function of the lung is fundamental to understanding the pathogenesis of pulmonary disease and how to design and deliver better treatments and measure response to intervention. Magnetic resonance imaging (MRI) with the hyperpolarised noble gases helium-3 ((3)He) and xenon-129 ((129)Xe) provides both structural and functional pulmonary measurements, and because it does not require the use of x-rays or other ionising radiation, offers the potential for intensive serial and longitudinal studies in paediatric patients. These facts are particularly important in the evaluation of chronic lung diseases such as asthma and cystic fibrosis- both of which can be considered paediatric respiratory diseases with unmet therapy needs. This review discusses MRI-based imaging methods with a focus on hyperpolarised gas MRI. We also discuss the strengths and limitations as well as the future work required for clinical translation towards paediatric respiratory disease.
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Affiliation(s)
- Miranda Kirby
- Imaging Research Laboratories, Robarts Research Institute, London, Canada.
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Mugler JP, Altes TA. Hyperpolarized 129Xe MRI of the human lung. J Magn Reson Imaging 2013; 37:313-31. [PMID: 23355432 DOI: 10.1002/jmri.23844] [Citation(s) in RCA: 240] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 08/29/2012] [Indexed: 11/07/2022] Open
Abstract
By permitting direct visualization of the airspaces of the lung, magnetic resonance imaging (MRI) using hyperpolarized gases provides unique strategies for evaluating pulmonary structure and function. Although the vast majority of research in humans has been performed using hyperpolarized (3)He, recent contraction in the supply of (3)He and consequent increases in price have turned attention to the alternative agent, hyperpolarized (129) Xe. Compared to (3)He, (129)Xe yields reduced signal due to its smaller magnetic moment. Nonetheless, taking advantage of advances in gas-polarization technology, recent studies in humans using techniques for measuring ventilation, diffusion, and partial pressure of oxygen have demonstrated results for hyperpolarized (129)Xe comparable to those previously demonstrated using hyperpolarized (3)He. In addition, xenon has the advantage of readily dissolving in lung tissue and blood following inhalation, which makes hyperpolarized (129)Xe particularly attractive for exploring certain characteristics of lung function, such as gas exchange and uptake, which cannot be accessed using (3)He. Preliminary results from methods for imaging (129) Xe dissolved in the human lung suggest that these approaches will provide new opportunities for quantifying relationships among gas delivery, exchange, and transport, and thus show substantial potential to broaden our understanding of lung disease. Finally, recent changes in the commercial landscape of the hyperpolarized-gas field now make it possible for this innovative technology to move beyond the research laboratory.
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Affiliation(s)
- John P Mugler
- Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
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Insights into pediatric asthma with hyperpolarized magnetic resonance imaging of the lung. J Allergy Clin Immunol 2013; 131:377-8. [PMID: 23374266 DOI: 10.1016/j.jaci.2012.12.669] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 12/12/2012] [Indexed: 11/23/2022]
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Kirby M, Svenningsen S, Kanhere N, Owrangi A, Wheatley A, Coxson HO, Santyr GE, Paterson NAM, McCormack DG, Parraga G. Pulmonary ventilation visualized using hyperpolarized helium-3 and xenon-129 magnetic resonance imaging: differences in COPD and relationship to emphysema. J Appl Physiol (1985) 2013; 114:707-15. [DOI: 10.1152/japplphysiol.01206.2012] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In subjects with chronic obstructive pulmonary disease (COPD), hyperpolarized xenon-129 (129Xe) magnetic resonance imaging (MRI) reveals significantly greater ventilation defects than hyperpolarized helium-3 (3He) MRI. The physiological and/or morphological determinants of ventilation defects and the differences observed between hyperpolarized 3He and 129Xe MRI are not yet understood. Here we aimed to determine the structural basis for the differences in ventilation observed between 3He and 129Xe MRI in subjects with COPD using apparent diffusion coefficients (ADC) and computed tomography (CT). Ten COPD ex-smokers provided written, informed consent and underwent MRI, CT, spirometry, and plethysmography. 3He and 129Xe MRI ventilation volume was generated using semiautomated segmentation, and ADC maps were registered to generate ADC values for lung regions of interest ventilated by both gases (ADCHX) and by 3He gas only (ADCHO). CT wall area percentage and the lowest 15th percentile point of the CT lung density histogram (HU15%) were also evaluated. For lung regions accessed by 3He gas only, mean 3He ADCHO was significantly greater than for regions accessed by both gases (ADCHO = 0.503 ± 0.119 cm2/s, ADCHX = 0.470 ± 0.125 cm2/s, P < 0.0001). The difference between 3He and 129Xe ventilation volume was significantly correlated with CT HU15% ( r = −65, P = 0.04) and 3He ADCHO ( r = 0.70, P = 0.02), but not CT wall area percentage ( r = −0.34, P = 0.33). In conclusion, in this small study in COPD subjects, we observed significantly decreased 129Xe MRI ventilation compared with 3He MRI, and these regions of decreased 129Xe ventilation were spatially and significantly correlated with regions of increased pulmonary emphysema, but not airway wall thickness.
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Affiliation(s)
- Miranda Kirby
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Sarah Svenningsen
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Nikhil Kanhere
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada
| | - Amir Owrangi
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada
| | - Andrew Wheatley
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Harvey O. Coxson
- Department of Radiology & James Hogg Research Centre, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada; and
| | - Giles E. Santyr
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
| | - Nigel A. M. Paterson
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Division of Respirology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada
| | - David G. McCormack
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Division of Respirology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada
| | - Grace Parraga
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
- Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada
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Ouriadov A, Farag A, Kirby M, McCormack DG, Parraga G, Santyr GE. Lung morphometry using hyperpolarized 129
Xe apparent diffusion coefficient anisotropy in chronic obstructive pulmonary disease. Magn Reson Med 2013; 70:1699-706. [DOI: 10.1002/mrm.24595] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 11/19/2012] [Accepted: 11/20/2012] [Indexed: 12/27/2022]
Affiliation(s)
- Alexei Ouriadov
- Ph.D., Imaging Research Laboratories; Robarts Research Institute; Western University, London Ontario Canada
| | - Adam Farag
- Ph.D., Imaging Research Laboratories; Robarts Research Institute; Western University, London Ontario Canada
| | - Miranda Kirby
- Ph.D., Imaging Research Laboratories; Robarts Research Institute; Western University, London Ontario Canada
- Department of Medical Biophysics; Western University; London Ontario Canada
| | | | - Grace Parraga
- Ph.D., Imaging Research Laboratories; Robarts Research Institute; Western University, London Ontario Canada
- Department of Medical Biophysics; Western University; London Ontario Canada
- Department of Medical Imaging; Western University; London Ontario Canada
| | - Giles E. Santyr
- Ph.D., Imaging Research Laboratories; Robarts Research Institute; Western University, London Ontario Canada
- Department of Medical Biophysics; Western University; London Ontario Canada
- Department of Medical Imaging; Western University; London Ontario Canada
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Kirby M, Svenningsen S, Owrangi A, Wheatley A, Farag A, Ouriadov A, Santyr GE, Etemad-Rezai R, Coxson HO, McCormack DG, Parraga G. Hyperpolarized3He and129Xe MR Imaging in Healthy Volunteers and Patients with Chronic Obstructive Pulmonary Disease. Radiology 2012; 265:600-10. [DOI: 10.1148/radiol.12120485] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Shukla Y, Wheatley A, Kirby M, Svenningsen S, Farag A, Santyr GE, Paterson NA, McCormack DG, Parraga G. Hyperpolarized 129Xe magnetic resonance imaging: tolerability in healthy volunteers and subjects with pulmonary disease. Acad Radiol 2012; 19:941-51. [PMID: 22591724 DOI: 10.1016/j.acra.2012.03.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 03/27/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
Abstract
RATIONALE AND OBJECTIVES The objective of this study was to evaluate the tolerability of hyperpolarized (129)Xe gas inhaled from functional residual capacity and magnetic resonance imaging in healthy subjects and those with pulmonary disease. MATERIALS AND METHODS Twelve healthy volunteers (mean age, 59 ± 17 years), seven subjects with asthma (mean age, 47 ± 7 years), 10 subjects with chronic obstructive pulmonary disease (mean age, 74 ± 4 years), three subjects with cystic fibrosis (mean age, 27 ± 10 years), and a single subject with radiation-induced lung injury (age, 66 years) were enrolled and evaluated over 43 visits with 136 anoxic inhalations of 500 mL (129)Xe gas mixed with 500 mL (4)He gas. Oxygen saturation and heart rate were monitored during the breath-hold and imaging; subjects were queried for adverse events (AEs) before and immediately following gas inhalation and for 24 hours after the last dose. RESULTS No subjects withdrew from the study or reported serious, hypoxic, or severe AEs. Over the course of 136 dose administrations, two mild AEs (1%) were reported in two different subjects (two of 33 [6%]). One of these AEs (light-headedness) was temporally related and judged as possibly related to (129)Xe administration and resolved without treatment within 2 minutes. Statistically significant but clinically insignificant changes in oxygen saturation and heart rate were observed after inhalation (P < .001), and both resolved 1 minute later, with no difference between subject groups. CONCLUSIONS Inhalation of hyperpolarized (129)Xe gas and subsequent magnetic resonance imaging were well tolerated in healthy subjects and ambulatory subjects with obstructive and restrictive pulmonary disease.
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Washko GR, Parraga G, Coxson HO. Quantitative pulmonary imaging using computed tomography and magnetic resonance imaging. Respirology 2012; 17:432-44. [PMID: 22142490 DOI: 10.1111/j.1440-1843.2011.02117.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Measurements of lung function, including spirometry and body plethesmography, are easy to perform and are the current clinical standard for assessing disease severity. However, these lung functional techniques do not adequately explain the observed variability in clinical manifestations of disease and offer little insight into the relationship of lung structure and function. Lung imaging and the image-based assessment of lung disease has matured to the extent that it is common for clinical, epidemiologic and genetic investigation to have a component dedicated to image analysis. There are several exciting imaging modalities currently being used for the non-invasive study of lung anatomy and function. In this review, we will focus on two of them; X-ray computed tomography and magnetic resonance imaging. Following a brief introduction of each method, we detail some of the most recent work being done to characterize smoking-related lung disease and the clinical applications of such knowledge.
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Affiliation(s)
- George R Washko
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
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Kirby M, Heydarian M, Wheatley A, McCormack DG, Parraga G. Evaluating bronchodilator effects in chronic obstructive pulmonary disease using diffusion-weighted hyperpolarized helium-3 magnetic resonance imaging. J Appl Physiol (1985) 2012; 112:651-7. [DOI: 10.1152/japplphysiol.01295.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The objective of this study was to evaluate the regional effects of bronchodilator administration in chronic obstructive pulmonary disease (COPD) using hyperpolarized helium-3 (3He) MRI apparent diffusion coefficient (ADC). Ten COPD ex-smokers provided written, informed consent and underwent diffusion-weighted, hyperpolarized 3He MRI, spirometry, and plethysmography before and 25 ± 2 min after bronchodilator administration. Pre- and postsalbutamol whole-lung (WL) ADC maps were generated and registered together to identify the lung regions containing the 3He signal at both time points, and mean ADC within those regions of interest (ROI) was determined for a measurement of previously ventilated ROI ADC (ADCP). Lung ROI with 3He signal at both time points was used as a binary mask on postsalbutamol WL ADC maps to obtain an ADC measurement for newly ventilated ROI (ADCN). Postsalbutamol, no significant differences were detected in WL ADC ( P = 0.516). There were no significant differences between ADCN and ADCP postsalbutamol ( P = 1.00), suggesting that the ADCN lung regions were not more emphysematous than the lung ROI participating in ventilation before bronchodilator administration. Postsalbutamol, a statistically significant decrease in ADCP ( P = 0.01) was detected, and there were significant differences between ADCP in the most anterior and most posterior image slices ( P = 0.02), suggesting a reduction in regional gas trapping following bronchodilator administration. Regional evaluation of tissue microstructure using hyperpolarized 3He MRI ADC provides insights into lung alterations that accompany improvements in regional 3He gas distribution after bronchodilator administration.
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Affiliation(s)
- Miranda Kirby
- Department of Medical Biophysics, The University of Western Ontario
- Imaging Research Laboratories, Robarts Research Institute; and
| | | | - Andrew Wheatley
- Imaging Research Laboratories, Robarts Research Institute; and
| | | | - Grace Parraga
- Department of Medical Biophysics, The University of Western Ontario
- Imaging Research Laboratories, Robarts Research Institute; and
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Canada
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Kirby M, Heydarian M, Svenningsen S, Wheatley A, McCormack DG, Etemad-Rezai R, Parraga G. Hyperpolarized 3He magnetic resonance functional imaging semiautomated segmentation. Acad Radiol 2012; 19:141-52. [PMID: 22104288 DOI: 10.1016/j.acra.2011.10.007] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 10/05/2011] [Accepted: 10/05/2011] [Indexed: 12/24/2022]
Abstract
RATIONALE AND OBJECTIVES To improve intra- and interobserver variability and enable the use of functional magnetic resonance imaging (MRI) for multicenter, multiobserver studies, we generated a semiautomated segmentation method for hyperpolarized helium-3 ((3)He) MRI. Therefore the objective of this study was to compare the reproducibility and spatial agreement of manual and semiautomated segmentation of (3)He MRI ventilation defect volume (VDV) and ventilation volume (VV) in subjects with asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF). MATERIALS AND METHODS The multistep semiautomated segmentation method we developed employed hierarchical K-means clustering to classify (3)He MRI pixel intensity values into five user-determined clusters ranging from signal void to hyperintense. A seeded region-growing algorithm was also used to segment the (1)H MRI thoracic cavity for coregistration to the (3)He cluster-map, generating VDV and VV. RESULTS We compared manual segmentation performed by an expert observer and semiautomated measurements of (3)He MRI VDV and observed strong significant correlations between the volumes generated using each method (asthma, n = 5, r = 0.89, P < .0001; COPD, n = 5, r = 0.84, P < .0001; CF, n = 5, r = 0.89, P < .0001). Semiautomated VDV had high interobserver reproducibility (coefficient of variation [CV] = 7%, intraclass correlation coefficient [ICC] = 0.96); intraobserver reproducibility was significantly higher for semiautomated (CV = 5%, ICC = 1.00) compared to manual VDV (CV = 12%, ICC = 0.98). Spatial agreement for VV determined using the Dice coefficient (D) was also high for all disease states (asthma, D = 0.95; COPD, D = 0.88; CF, D = 0.90). CONCLUSIONS Semiautomated segmentation (3)He MRI provides excellent inter- and intraobserver precision with high spatial and quantitative agreement with manual measurements enabling its use in longitudinal studies.
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Mathew L, Kirby M, Etemad-Rezai R, Wheatley A, McCormack DG, Parraga G. Hyperpolarized 3He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease. Eur J Radiol 2011; 79:140-6. [DOI: 10.1016/j.ejrad.2009.10.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 10/16/2009] [Accepted: 10/21/2009] [Indexed: 10/20/2022]
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Takenaka D, Puderbach M, Ohno Y, Risse F, Ley S, Sugimura K, Kauczor HU. Oxygen-enhanced lung magnetic resonance imaging: influence of inversion pulse slice selectivity on inversion recovery half-Fourier single-shot turbo spin-echo signal. Jpn J Radiol 2011; 29:244-50. [DOI: 10.1007/s11604-010-0548-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 12/02/2010] [Indexed: 10/18/2022]
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Dominguez-Viqueira W, Ouriadov A, O'Halloran R, Fain SB, Santyr GE. Signal-to-noise ratio for hyperpolarized ³He MR imaging of human lungs: a 1.5 T and 3 T comparison. Magn Reson Med 2011; 66:1400-4. [PMID: 21523821 DOI: 10.1002/mrm.22920] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 01/21/2011] [Accepted: 02/18/2011] [Indexed: 11/08/2022]
Abstract
The signal-to-noise ratio in hyperpolarized noble gas MR imaging is expected to be independent of field strength at frequencies typical of clinical systems (e.g., 1.5 T), where body noise dominates over coil noise. Furthermore, at higher fields (e.g., 3 T), the SNR of lung images may decline due to decreases in T(2) originating from increases in susceptibility-induced field gradients at the air-tissue interface. In this work, the SNR of hyperpolarized (3) He lung imaging at two commonly used clinical field strengths (1.5 T and 3 T) were compared in the same volunteers. Thermally polarized and hyperpolarized (3) He phantoms were used to account for differences in MR imaging system and (3) He polarizer performance, respectively, at the two field strengths. After correcting for T(2) values measured at 1.5 T (16 ± 2 ms) and 3 T (7 ± 1 ms), no significant difference in image SNR between the two field strengths was observed, consistent with theory.
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Aysola R, de Lange EE, Castro M, Altes TA. Demonstration of the heterogeneous distribution of asthma in the lungs using CT and hyperpolarized helium-3 MRI. J Magn Reson Imaging 2011; 32:1379-87. [PMID: 21105142 DOI: 10.1002/jmri.22388] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Asthma is a chronic inflammatory disease that affects both the large and small airways and results in bronchoconstriction, mucous hypersecretion, smooth muscle hypertrophy, and subepithelial fibrosis. To gain insight into the pathophysiology of asthma, chest computed tomography (CT) has been investigated as a noninvasive method to evaluate airway wall thickness of medium and large airways. Hyperpolarized gas MRI can assess the functional alterations of airflow within the lung resulting from the structural changes in the airways. In this article, we review the application of CT-based techniques and hyperpolarized gas MRI to study structural and functional changes in asthma. From the result of studies with CT and hyperpolarized gas MRI, it is becoming apparent that asthma has a regional distribution within the lung, that is, some areas of the lung are more affected than others. Furthermore, there appears to be some persistence to this distribution which may explain the observed patterns of airway remodeling and provide targets for localized therapies such as local application of anti-inflammatory agents or bronchial thermoplasty. Thus, cross sectional imaging in asthma is providing new insights into the pathophysiology of the disease and has the potential to become essential in the guidance of localized treatments.
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Affiliation(s)
- Ravi Aysola
- University of California Los Angeles Medical Center, Department of Medicine, Pulmonary and Critical Care Medicine, Los Angeles, California, USA
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