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Donovan GM. Pillars of Theoretical Biology: Airway stability and heterogeneity in the constricted lung. J Theor Biol 2023; 575:111628. [PMID: 37778618 DOI: 10.1016/j.jtbi.2023.111628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, 1142, New Zealand.
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Foo CT, Langton D, Thompson BR, Thien F. Functional lung imaging using novel and emerging MRI techniques. Front Med (Lausanne) 2023; 10:1060940. [PMID: 37181360 PMCID: PMC10166823 DOI: 10.3389/fmed.2023.1060940] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 04/03/2023] [Indexed: 05/16/2023] Open
Abstract
Respiratory diseases are leading causes of death and disability in the world. While early diagnosis is key, this has proven difficult due to the lack of sensitive and non-invasive tools. Computed tomography is regarded as the gold standard for structural lung imaging but lacks functional information and involves significant radiation exposure. Lung magnetic resonance imaging (MRI) has historically been challenging due to its short T2 and low proton density. Hyperpolarised gas MRI is an emerging technique that is able to overcome these difficulties, permitting the functional and microstructural evaluation of the lung. Other novel imaging techniques such as fluorinated gas MRI, oxygen-enhanced MRI, Fourier decomposition MRI and phase-resolved functional lung imaging can also be used to interrogate lung function though they are currently at varying stages of development. This article provides a clinically focused review of these contrast and non-contrast MR imaging techniques and their current applications in lung disease.
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Affiliation(s)
- Chuan T. Foo
- Department of Respiratory Medicine, Eastern Health, Melbourne, VIC, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
| | - David Langton
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
- Department of Thoracic Medicine, Peninsula Health, Frankston, VIC, Australia
| | - Bruce R. Thompson
- Melbourne School of Health Science, Melbourne University, Melbourne, VIC, Australia
| | - Francis Thien
- Department of Respiratory Medicine, Eastern Health, Melbourne, VIC, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
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3
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DOĞANAY Ö. Computational investigation of fitting for calculation of signal dynamics from hyperpolarized xenon-129 Gas MRI. EGE TIP DERGISI 2022. [DOI: 10.19161/etd.1085607] [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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Kooner HK, McIntosh MJ, Desaigoudar V, Rayment JH, Eddy RL, Driehuys B, Parraga G. Pulmonary functional MRI: Detecting the structure-function pathologies that drive asthma symptoms and quality of life. Respirology 2022; 27:114-133. [PMID: 35008127 PMCID: PMC10025897 DOI: 10.1111/resp.14197] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/09/2021] [Accepted: 12/12/2021] [Indexed: 12/21/2022]
Abstract
Pulmonary functional MRI (PfMRI) using inhaled hyperpolarized, radiation-free gases (such as 3 He and 129 Xe) provides a way to directly visualize inhaled gas distribution and ventilation defects (or ventilation heterogeneity) in real time with high spatial (~mm3 ) resolution. Both gases enable quantitative measurement of terminal airway morphology, while 129 Xe uniquely enables imaging the transfer of inhaled gas across the alveolar-capillary tissue barrier to the red blood cells. In patients with asthma, PfMRI abnormalities have been shown to reflect airway smooth muscle dysfunction, airway inflammation and remodelling, luminal occlusions and airway pruning. The method is rapid (8-15 s), cost-effective (~$300/scan) and very well tolerated in patients, even in those who are very young or very ill, because unlike computed tomography (CT), positron emission tomography and single-photon emission CT, there is no ionizing radiation and the examination takes only a few seconds. However, PfMRI is not without limitations, which include the requirement of complex image analysis, specialized equipment and additional training and quality control. We provide an overview of the three main applications of hyperpolarized noble gas MRI in asthma research including: (1) inhaled gas distribution or ventilation imaging, (2) alveolar microstructure and finally (3) gas transfer into the alveolar-capillary tissue space and from the tissue barrier into red blood cells in the pulmonary microvasculature. We highlight the evidence that supports a deeper understanding of the mechanisms of asthma worsening over time and the pathologies responsible for symptoms and disease control. We conclude with a summary of approaches that have the potential for integration into clinical workflows and that may be used to guide personalized treatment planning.
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Affiliation(s)
- Harkiran K Kooner
- Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Marrissa J McIntosh
- Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Vedanth Desaigoudar
- Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Jonathan H Rayment
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rachel L Eddy
- Centre of Heart Lung Innovation, Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bastiaan Driehuys
- Center for In Vivo Microscopy, Duke University Medical Centre, Durham, North Carolina, USA
| | - Grace Parraga
- Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
- Division of Respirology, Department of Medicine, Western University, London, Ontario, Canada
- School of Biomedical Engineering, Western University, London, Ontario, Canada
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5
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Benlala I, Dournes G, Girodet PO, Benkert T, Laurent F, Berger P. Evaluation of bronchial wall thickness in asthma using magnetic resonance imaging. Eur Respir J 2021; 59:13993003.00329-2021. [PMID: 34049945 DOI: 10.1183/13993003.00329-2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 05/20/2021] [Indexed: 11/05/2022]
Abstract
BACKGROUND Bronchial thickening is a pathological feature of asthma that has been evaluated using computed tomography (CT), an ionised radiation technique. Magnetic Resonance Imaging (MRI) with Ultrashort Echo Time (UTE) pulse sequences could be an alternative to CT. OBJECTIVES To measure bronchial dimensions using MRI-UTE in asthmatic patients, by evaluating the accuracy and agreement with CT, by comparing severe and non-severe asthma and by correlating with pulmonary function tests. METHODS We assessed bronchial dimensions (wall area (WA), lumen area (LA), normalised wall area (WA%), and wall thickness (WT)) by MRI-UTE and CT in 15 non-severe and 15 age- and sex-matched severe asthmatic patients (NCT03089346). Accuracy and agreement between MRI and CT was evaluated by paired t-tests and Bland-Altman analysis. Reproducibility was assessed by intra-class correlation coefficient and Bland-Altman analysis. Comparison between non-severe and severe asthmatic parameters was performed by Student-t, Mann-Whitney or Fisher's Exact tests. Correlations were assessed by Pearson or Spearman coefficients. RESULTS LA, WA%, and WT were not significantly different between MRI-UTE and CT, with good correlations and concordance. Inter- and intra-observer reproducibility was moderate to good. WA% and WT were both higher in severe than in non-severe asthmatic patients. WA, WA% and WT were all negatively correlated with FEV1. CONCLUSION We demonstrated that MRI-UTE is an accurate and reliable radiation-free method to assess bronchial wall dimensions in asthma, with enough spatial resolution to differentiate severe from non-severe asthma.
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Affiliation(s)
- Ilyes Benlala
- Univ. Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, Bordeaux, France.,CHU Bordeaux, Service de Radiologie et d'imagerie diagnostique et interventionnelle, CIC-P 1401, Service d'Exploration Fonctionnelle Respiratoire, Bordeaux, France.,INSERM, Centre de Recherche Cardio-thoracique de Bordeaux (U1045), Centre d'Investigation Clinique (CIC-P 1401), Bordeaux, France
| | - Gaël Dournes
- Univ. Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, Bordeaux, France.,CHU Bordeaux, Service de Radiologie et d'imagerie diagnostique et interventionnelle, CIC-P 1401, Service d'Exploration Fonctionnelle Respiratoire, Bordeaux, France.,INSERM, Centre de Recherche Cardio-thoracique de Bordeaux (U1045), Centre d'Investigation Clinique (CIC-P 1401), Bordeaux, France
| | - Pierre-Olivier Girodet
- Univ. Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, Bordeaux, France.,CHU Bordeaux, Service de Radiologie et d'imagerie diagnostique et interventionnelle, CIC-P 1401, Service d'Exploration Fonctionnelle Respiratoire, Bordeaux, France.,INSERM, Centre de Recherche Cardio-thoracique de Bordeaux (U1045), Centre d'Investigation Clinique (CIC-P 1401), Bordeaux, France
| | - Thomas Benkert
- MR application predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - François Laurent
- Univ. Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, Bordeaux, France.,CHU Bordeaux, Service de Radiologie et d'imagerie diagnostique et interventionnelle, CIC-P 1401, Service d'Exploration Fonctionnelle Respiratoire, Bordeaux, France.,INSERM, Centre de Recherche Cardio-thoracique de Bordeaux (U1045), Centre d'Investigation Clinique (CIC-P 1401), Bordeaux, France
| | - Patrick Berger
- Univ. Bordeaux, Centre de Recherche Cardio-thoracique de Bordeaux, Bordeaux, France .,CHU Bordeaux, Service de Radiologie et d'imagerie diagnostique et interventionnelle, CIC-P 1401, Service d'Exploration Fonctionnelle Respiratoire, Bordeaux, France.,INSERM, Centre de Recherche Cardio-thoracique de Bordeaux (U1045), Centre d'Investigation Clinique (CIC-P 1401), Bordeaux, France
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Gefter WB, Lee KS, Schiebler ML, Parraga G, Seo JB, Ohno Y, Hatabu H. Pulmonary Functional Imaging: Part 2-State-of-the-Art Clinical Applications and Opportunities for Improved Patient Care. Radiology 2021; 299:524-538. [PMID: 33847518 DOI: 10.1148/radiol.2021204033] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pulmonary functional imaging may be defined as the regional quantification of lung function by using primarily CT, MRI, and nuclear medicine techniques. The distribution of pulmonary physiologic parameters, including ventilation, perfusion, gas exchange, and biomechanics, can be noninvasively mapped and measured throughout the lungs. This information is not accessible by using conventional pulmonary function tests, which measure total lung function without viewing the regional distribution. The latter is important because of the heterogeneous distribution of virtually all lung disorders. Moreover, techniques such as hyperpolarized xenon 129 and helium 3 MRI can probe lung physiologic structure and microstructure at the level of the alveolar-air and alveolar-red blood cell interface, which is well beyond the spatial resolution of other clinical methods. The opportunities, challenges, and current stage of clinical deployment of pulmonary functional imaging are reviewed, including applications to chronic obstructive pulmonary disease, asthma, interstitial lung disease, pulmonary embolism, and pulmonary hypertension. Among the challenges to the deployment of pulmonary functional imaging in routine clinical practice are the need for further validation, establishment of normal values, standardization of imaging acquisition and analysis, and evidence of patient outcomes benefit. When these challenges are addressed, it is anticipated that pulmonary functional imaging will have an expanding role in the evaluation and management of patients with lung disease.
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Affiliation(s)
- Warren B Gefter
- From the Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, 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, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, 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, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Grace Parraga
- From the Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, 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, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Yoshiharu Ohno
- From the Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Hiroto Hatabu
- From the Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, South Korea (K.S.L.); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wis (M.L.S.); Departments of Medicine and Medical Biophysics, Robarts Research Institute, Western University, London, Canada (G.P.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Radiology and Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan (Y.O.); and Center for Pulmonary Functional Imaging, Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
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Eddy RL, Matheson AM, Svenningsen S, Knipping D, Licskai C, McCormack DG, Parraga G. Nonidentical Twins With Asthma: Spatially Matched CT Airway and MRI Ventilation Abnormalities. Chest 2020; 156:e111-e116. [PMID: 31812208 DOI: 10.1016/j.chest.2019.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/09/2019] [Accepted: 08/04/2019] [Indexed: 11/29/2022] Open
Abstract
Recent pulmonary functional MRI findings of spatially and temporally persistent ventilation abnormalities in patients with asthma contrast with previous in silico modeling studies that suggest that in asthma, ventilation defects may be randomly distributed. In a case study that used pulmonary MRI, CT imaging, and pulmonary function tests, we prospectively evaluated over the course of 7 years, nonidentical female adult twins, each with a lifelong history of asthma. We evaluated pulmonary function and MRI ventilation heterogeneity at baseline and follow-up after 7 years. In both twins, there was a spatially identical MRI ventilation defect and an abnormal subsegmental left-sided upper lobe airway that persisted in the same spatial location after 7 years. If ventilation defects are randomly distributed, this bears a probability of approximately one per 130,000 people. Our MRI observations in related patients with asthma suggest that ventilation abnormalities may not be randomly distributed in patients with asthma and persist distal to airway abnormalities for long periods of time.
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Affiliation(s)
- Rachel L Eddy
- Robarts Research Institute, Western University, London; Department of Medical Biophysics, Western University, London
| | - Alexander M Matheson
- Robarts Research Institute, Western University, London; Department of Medical Biophysics, Western University, London
| | - Sarah Svenningsen
- Department of Medicine, McMaster University, Hamilton; Firestone Institute for Respiratory Health, St Joseph's Healthcare, Hamilton
| | | | - Christopher Licskai
- Division of Respirology, Department of Medicine, 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; Department of Medical Biophysics, Western University, London; Division of Respirology, Department of Medicine, Western University, London, ON, Canada.
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8
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Svenningsen S, Eddy RL, Kjarsgaard M, Parraga G, Nair P. Effects of Anti-T2 Biologic Treatment on Lung Ventilation Evaluated by MRI in Adults With Prednisone-Dependent Asthma. Chest 2020; 158:1350-1360. [PMID: 32428511 DOI: 10.1016/j.chest.2020.04.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/17/2020] [Accepted: 04/22/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The functional consequence of airway obstruction in asthma can be regionally measured using inhaled gas MRI. Ventilation defects visualized by MRI persist post-bronchodilator in patients with severe asthma with uncontrolled sputum eosinophilia and may be due to eosinophil-driven airway pathology that is responsive to "anti-T2" therapy. RESEARCH QUESTION Do anti-T2 therapies that clear eosinophils from the airway lumen decrease ventilation defects, measured by inhaled gas MRI, in adults with prednisone-dependent asthma? STUDY DESIGN AND METHODS Inhaled hyperpolarized gas MRI was performed before and after bronchodilation in 10 prednisone-dependent patients with asthma with uncontrolled eosinophilic bronchitis (sputum eosinophils ≥3%) at baseline and 558 (100-995) days later when their eosinophilic bronchitis had been controlled (sputum eosinophils <3%) by additional anti-T2 therapy. The effect of anti-T2 therapy on ventilation defects, quantified as the MRI ventilation-defect-percent (VDP), was evaluated before and after bronchodilation for all patients and compared between patients dichotomized based on the median percentage of sputum eosinophils at baseline (15.8%). RESULTS MRI VDP was improved pre- (ΔVDP+anti-T2: -3% ± 4%, P = .02) and post-bronchodilator (ΔVDP+anti-T2: -3% ± 4%; P = .04) after additional anti-T2 therapy that controlled eosinophilic bronchitis (n = 2 mepolizumab, n = 2 reslizumab, n = 3 benralizumab, n = 1 dupilumab, n = 2 increased daily prednisone). A greater post-bronchodilator ΔVDP+anti-T2 was observed in those patients with median or higher percentage of sputum eosinophils at baseline (≥15.8%; P = .01). In 7 of 10 patients with asthma, residual ventilation defects persisted despite bronchodilator and anti-T2 therapy. INTERPRETATION Controlling sputum eosinophilia with anti-T2 therapies improves ventilation defects, measured by inhaled gas MRI, in adults with prednisone-dependent asthma.
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Affiliation(s)
- Sarah Svenningsen
- Firestone Institute for Respiratory Health, St Joseph's Healthcare, Hamilton, ON, Canada; Department of Medicine, McMaster University, Hamilton, ON, Canada.
| | - Rachel L Eddy
- Robarts Research Institute, University of Western Ontario, ON, Canada; Department of Medical Biophysics, Western University, London, ON, Canada
| | - Melanie Kjarsgaard
- Firestone Institute for Respiratory Health, St Joseph's Healthcare, Hamilton, ON, Canada
| | - Grace Parraga
- Robarts Research Institute, University of Western Ontario, ON, Canada; Department of Medical Biophysics, Western University, London, ON, Canada
| | - Parameswaran Nair
- Firestone Institute for Respiratory Health, St Joseph's Healthcare, Hamilton, ON, Canada; Department of Medicine, McMaster University, Hamilton, ON, Canada
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9
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Doganay O, Chen M, Matin T, Rigolli M, Phillips JA, McIntyre A, Gleeson FV. Magnetic resonance imaging of the time course of hyperpolarized 129Xe gas exchange in the human lungs and heart. Eur Radiol 2018; 29:2283-2292. [PMID: 30519929 PMCID: PMC6443604 DOI: 10.1007/s00330-018-5853-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/27/2018] [Accepted: 10/23/2018] [Indexed: 12/23/2022]
Abstract
Purpose To perform magnetic resonance imaging (MRI), human lung imaging, and quantification of the gas-transfer dynamics of hyperpolarized xenon-129 (HPX) from the alveoli into the blood plasma. Materials and methods HPX MRI with iterative decomposition of water and fat with echo asymmetry and least-square estimation (IDEAL) approach were used with multi-interleaved spiral k-space sampling to obtain HPX gas and dissolved phase images. IDEAL time-series images were then obtained from ten subjects including six normal subjects and four patients with pulmonary emphysema to test the feasibility of the proposed technique for capturing xenon-129 gas-transfer dynamics (XGTD). The dynamics of xenon gas diffusion over the entire lung was also investigated by measuring the signal intensity variations between three regions of interest, including the left and right lungs and the heart using Welch’s t test. Results The technique enabled the acquisition of HPX gas and dissolved phase compartment images in a single breath-hold interval of 8 s. The y-intersect of the XGTD curves were also found to be statistically lower in the patients with lung emphysema than in the healthy group (p < 0.05). Conclusion This time-series IDEAL technique enables the visualization and quantification of inhaled xenon from the alveoli to the left ventricle with a clinical gradient strength magnet during a single breath-hold, in healthy and diseased lungs. Key Points • The proposed hyperpolarized xenon-129 gas and dissolved magnetic resonance imaging technique can provide regional and temporal measurements of xenon-129 gas-transfer dynamics. • Quantitative measurement of xenon-129 gas-transfer dynamics from the alveolar to the heart was demonstrated in normal subjects and pulmonary emphysema. • Comparison of gas-transfer dynamics in normal subjects and pulmonary emphysema showed that the proposed technique appears sensitive to changes affecting the alveoli, pulmonary interstitium, and capillaries. Electronic supplementary material The online version of this article (10.1007/s00330-018-5853-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ozkan Doganay
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK. .,Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Old Rd, Oxford, OX3 7LE, UK.
| | - Mitchell Chen
- Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Old Rd, Oxford, OX3 7LE, UK
| | - Tahreema Matin
- Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Old Rd, Oxford, OX3 7LE, UK
| | - Marzia Rigolli
- University of Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK
| | - Julie-Ann Phillips
- Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Old Rd, Oxford, OX3 7LE, UK
| | - Anthony McIntyre
- Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Old Rd, Oxford, OX3 7LE, UK
| | - Fergus V Gleeson
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK.,Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Old Rd, Oxford, OX3 7LE, UK
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10
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Geier ET, Kubo K, Theilmann RJ, Prisk GK, Sá RC. The spatial pattern of methacholine bronchoconstriction recurs when supine, independently of posture during provocation, but does not recur between postures. J Appl Physiol (1985) 2018; 125:1720-1730. [PMID: 30188793 PMCID: PMC10392630 DOI: 10.1152/japplphysiol.00487.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The location of lung regions with compromised ventilation (often called ventilation defects) during a bronchoconstriction event may be influenced by posture. We aimed to determine the effect of prone vs. supine posture on the spatial pattern of methacholine-induced bronchoconstriction in six healthy adults (ages 21-41, three females) using specific ventilation imaging. Three postural conditions were chosen to assign the effect of posture to the drug administration and/or imaging phase of the experiment - supine methacholine administration followed by supine imaging, prone methacholine administration followed by supine imaging, and prone methacholine administration followed by prone imaging. The two conditions in which imaging was performed supine had similar spatial patterns of bronchoconstriction despite a change in posture during methacholine administration; the odds ratio for recurrent constriction was mean (SD) = 7.4 (3.9). Conversely, dissimilar spatial patterns of bronchoconstriction emerged when posture during imaging was changed; the odds ratio for recurrent constriction between the prone methacholine/supine imaging condition and the prone methacholine/prone imaging condition was 1.2 (0.9). Logistic regression showed that height above the dependent lung border was a significant negative predictor of constriction in the two supine imaging conditions (p<0.001 for each), but not in the prone imaging condition (p=0.20). These results show that the spatial pattern of methacholine bronchoconstriction is recurrent in the supine posture, regardless of whether methacholine is given prone or supine, but that prone posture during imaging eliminates that recurrent pattern and reduces its dependence on gravitational height.
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Affiliation(s)
- Eric T Geier
- Department of Medicine, University of California, San Diego, United States
| | - Kent Kubo
- Department of Medicine, University of California, San Diego
| | | | - Gordon Kim Prisk
- Department of Medicine and Radiology, University of California, San Diego, United States
| | - Rui Carlos Sá
- Medicine, University of California, San Diego, United States
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11
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Ash SY, Rahaghi FN, Come CE, Ross JC, Colon AG, Cardet-Guisasola JC, Dunican EM, Bleecker ER, Castro M, Fahy JV, Fain SB, Gaston BM, Hoffman EA, Jarjour NN, Mauger DT, Wenzel SE, Levy BD, San Jose Estepar R, Israel E. Pruning of the Pulmonary Vasculature in Asthma. The Severe Asthma Research Program (SARP) Cohort. Am J Respir Crit Care Med 2018; 198:39-50. [PMID: 29672122 PMCID: PMC6034125 DOI: 10.1164/rccm.201712-2426oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 04/19/2018] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Loss of the peripheral pulmonary vasculature, termed vascular pruning, is associated with disease severity in patients with chronic obstructive pulmonary disease. OBJECTIVES To determine if pulmonary vascular pruning is associated with asthma severity and exacerbations. METHODS We measured the total pulmonary blood vessel volume (TBV) and the blood vessel volume of vessels less than 5 mm2 in cross-sectional area (BV5) and of vessels less than 10 mm2 (BV10) in cross-sectional area on noncontrast computed tomographic scans of participants from the Severe Asthma Research Program. Lower values of the BV5 to TBV ratio (BV5/TBV) and the BV10 to TBV ratio (BV10/TBV) represented vascular pruning (loss of the peripheral pulmonary vasculature). MEASUREMENTS AND MAIN RESULTS Compared with healthy control subjects, patients with severe asthma had more pulmonary vascular pruning. Among those with asthma, those with poor asthma control had more pruning than those with well-controlled disease. Pruning of the pulmonary vasculature was also associated with lower percent predicted FEV1 and FVC, greater peripheral and sputum eosinophilia, and higher BAL serum amyloid A/lipoxin A4 ratio but not with low-attenuation area or with sputum neutrophilia. Compared with individuals with less pruning, individuals with the most vascular pruning had 150% greater odds of reporting an asthma exacerbation (odds ratio, 2.50; confidence interval, 1.05-5.98; P = 0.039 for BV10/TBV) and reported 45% more asthma exacerbations during follow-up (incidence rate ratio, 1.45; confidence interval, 1.02-2.06; P = 0.036 for BV10/TBV). CONCLUSIONS Pruning of the peripheral pulmonary vasculature is associated with asthma severity, control, and exacerbations, and with lung function and eosinophilia.
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Affiliation(s)
- Samuel Y. Ash
- Division of Pulmonary and Critical Care Medicine and
- Applied Chest Imaging Laboratory, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Farbod N. Rahaghi
- Division of Pulmonary and Critical Care Medicine and
- Applied Chest Imaging Laboratory, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Carolyn E. Come
- Division of Pulmonary and Critical Care Medicine and
- Applied Chest Imaging Laboratory, Brigham and Women’s Hospital, Boston, Massachusetts
| | - James C. Ross
- Applied Chest Imaging Laboratory, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Alysha G. Colon
- College of Medicine, University of Florida, Gainesville, Florida
| | | | - Eleanor M. Dunican
- St. Vincent’s University Hospital, University College Dublin, Dublin, Ireland
| | - Eugene R. Bleecker
- Division of Genetics, Genomics and Precision Medicine, University of Arizona, Tucson, Arizona
| | - Mario Castro
- Division of Pulmonary and Critical Care Medicine, Washington University, St. Louis, Missouri
| | - John V. Fahy
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, California
| | - Sean B. Fain
- Department of Medical Physics
- Department of Radiology
- Department of Biomedical Engineering, and
| | - Benjamin M. Gaston
- Division of Pediatric Allergy/Immunology and
- Division of Pediatric Pulmonology, Rainbow Babies and Children’s Hospital and Cleveland Medical Center, Cleveland, Ohio
| | - Eric A. Hoffman
- Department of Radiology
- Department of Biomedical Engineering, and
- Department of Medicine, University of Iowa, Iowa City, Iowa
| | - Nizar N. Jarjour
- Division of Pulmonary and Critical Care Medicine, University of Wisconsin, Madison, Wisconsin
| | - David T. Mauger
- Division of Biostatistics and Bioinformatics, Eberly College of Science, Penn State University, University Park, Pennsylvania; and
| | - Sally E. Wenzel
- Division of Pulmonary, Allergy and Critical Care, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Bruce D. Levy
- Division of Pulmonary and Critical Care Medicine and
| | - Raul San Jose Estepar
- Applied Chest Imaging Laboratory, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Elliot Israel
- Division of Pulmonary and Critical Care Medicine and
| | - SARP Investigators
- Division of Pulmonary and Critical Care Medicine and
- Applied Chest Imaging Laboratory, Brigham and Women’s Hospital, Boston, Massachusetts
- College of Medicine, University of Florida, Gainesville, Florida
- Division of Allergy and Immunology, Department of Medicine, University of South Florida, Tampa, Florida
- St. Vincent’s University Hospital, University College Dublin, Dublin, Ireland
- Division of Genetics, Genomics and Precision Medicine, University of Arizona, Tucson, Arizona
- Division of Pulmonary and Critical Care Medicine, Washington University, St. Louis, Missouri
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, California
- Department of Medical Physics
- Department of Radiology
- Department of Biomedical Engineering, and
- Division of Pulmonary and Critical Care Medicine, University of Wisconsin, Madison, Wisconsin
- Division of Pediatric Allergy/Immunology and
- Division of Pediatric Pulmonology, Rainbow Babies and Children’s Hospital and Cleveland Medical Center, Cleveland, Ohio
- Department of Radiology
- Department of Biomedical Engineering, and
- Department of Medicine, University of Iowa, Iowa City, Iowa
- Division of Biostatistics and Bioinformatics, Eberly College of Science, Penn State University, University Park, Pennsylvania; and
- Division of Pulmonary, Allergy and Critical Care, University of Pittsburgh, Pittsburgh, Pennsylvania
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12
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Geier ET, Neuhart I, Theilmann RJ, Prisk GK, Sá RC. Spatial persistence of reduced specific ventilation following methacholine challenge in the healthy human lung. J Appl Physiol (1985) 2018; 124:1222-1232. [PMID: 29420156 PMCID: PMC6008074 DOI: 10.1152/japplphysiol.01032.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 01/16/2018] [Accepted: 02/01/2018] [Indexed: 11/22/2022] Open
Abstract
Specific ventilation imaging was used to identify regions of the healthy lung (6 supine subjects, ages 21-41 yr, 3 men) that experienced a fall in specific ventilation following inhalation of methacholine. This test was repeated 1 wk later and 3 mo later to test for spatial recurrence. Our data showed that 53% confidence interval (CI; 46%, 59%) of volume elements that constricted during one methacholine challenge did so again in another and that this quantity did not vary with time; 46% CI (28%, 64%) recurred 1 wk later, and 56% CI (51%, 61%) recurred 3 mo later. Previous constriction was a strong predictor for future constriction. Volume elements that constricted during one challenge were 7.7 CI (5.2, 10.2) times more likely than nonconstricted elements to constrict in a second challenge, regardless of whether the second episode was 1 wk [7.7 CI (2.9, 12.4)] or 3 mo [7.7 CI (4.6, 10.8)] later. Furthermore, posterior lung elements were more likely to constrict following methacholine than anterior lung elements (volume fraction 0.43 ± 0.22 posterior vs. 0.10 ± 0.03 anterior; P = 0.005), and basal elements that constricted were more likely than their apical counterparts to do so persistently through all three trials (volume fraction 0.14 ± 0.04 basal vs. 0.04 ± 0.04 apical; P = 0.003). Taken together, this evidence suggests a physiological predisposition toward constriction in some lung elements, especially those located in the posterior and basal lung when the subject is supine. NEW & NOTEWORTHY The spatial pattern of bronchoconstriction following methacholine is persistent over time in healthy individuals, in whom chronic inflammation and airway remodeling are assumed to be absent. This suggests that regional lung inflation and airway structure may play dominant roles in determining the spatial pattern of methacholine bronchoconstriction.
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Affiliation(s)
- E. T. Geier
- Department of Medicine, University of California San Diego, San Diego, California
| | - I. Neuhart
- The Ohio State University, Columbus, Ohio
| | - R. J. Theilmann
- Department of Medicine, University of California San Diego, San Diego, California
| | - G. K. Prisk
- Department of Medicine, University of California San Diego, San Diego, California
| | - R. C. Sá
- Department of Medicine, University of California San Diego, San Diego, California
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13
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Abstract
PURPOSE OF REVIEW The present review aims to summarize the most recent evidence related to imaging and severe asthma, both with regard to advances in imaging research and to their current and potential clinical implications. RECENT FINDINGS Recent work in imaging in severe asthma has principally been using computed tomography (CT) and MRI, as well as the integration of the two. Some of the most notable findings include the use of CT imaging biomarkers to create unique clusters of asthmatics, and the use of co-registration to link CT images of airways with regional variation in ventilation in MRI. In addition, temporal studies have shown that some the ventilation defects found using MRI in asthmatics are intermittent and others are persistent, but both are associated with lower lung function. SUMMARY The role of imaging in severe asthma currently is primarily in the exclusion of comorbid or other conditions, or in the assessment for complications in the setting of acute decompensation. A rapidly expanding body of literature using CT and MRI suggests that these tools may soon be of utility in the chronic management of the disease.
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14
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Lui JK, Lutchen KR. The role of heterogeneity in asthma: a structure-to-function perspective. Clin Transl Med 2017; 6:29. [PMID: 28776171 PMCID: PMC5543015 DOI: 10.1186/s40169-017-0159-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/26/2017] [Indexed: 02/07/2023] Open
Abstract
A number of methods have evolved through the years in probing the dysfunction that impacts mechanics and ventilation in asthma. What has been consistently found is the notion of heterogeneity that is not only captured in the frequency dependence of lung mechanics measurements but also rendered on imaging as patchy diffuse areas of ventilation defects. The degree of heterogeneity has been linked to airway hyperresponsiveness, a hallmark feature of asthma. How these heterogeneous constriction patterns lead to functional impairment in asthma have only been recently explored using computational airway tree models. By synthesizing measurements of lung mechanics and advances in imaging, computational airway tree models serve as a powerful engine to accelerate our understanding of the physiologic changes that occur in asthma. This review will be focused on the current state of investigational work on the role of heterogeneity in asthma, specifically exploring the structural and functional relationships.
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Affiliation(s)
- Justin K. Lui
- Department of Medicine, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 USA
| | - Kenneth R. Lutchen
- Department of Biomedical Engineering, Boston University, Boston, MA 02215 USA
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15
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Kelly VJ, Hibbert KA, Kohli P, Kone M, Greenblatt EE, Venegas JG, Winkler T, Harris RS. Hypoxic Pulmonary Vasoconstriction Does Not Explain All Regional Perfusion Redistribution in Asthma. Am J Respir Crit Care Med 2017. [PMID: 28644040 DOI: 10.1164/rccm.201612-2438oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
RATIONALE Regional hypoventilation in bronchoconstricted patients with asthma is spatially associated with reduced perfusion, which is proposed to result from hypoxic pulmonary vasoconstriction (HPV). OBJECTIVES To determine the role of HPV in the regional perfusion redistribution in bronchoconstricted patients with asthma. METHODS Eight patients with asthma completed positron emission tomographic/computed tomographic lung imaging at baseline and after bronchoconstriction, breathing either room air or 80% oxygen (80% O2) on separate days. Relative perfusion, specific ventilation (sV), and gas fraction (Fgas) in the 25% of the lung with the lowest specific ventilation (sVlow) and the remaining lung (sVhigh) were quantified and compared. MEASUREMENTS AND MAIN RESULTS In the sVlow region, bronchoconstriction caused a significant decrease in sV under both room air and 80% O2 conditions (baseline vs. bronchoconstriction, mean ± SD, 1.02 ± 0.20 vs. 0.35 ± 0.19 and 1.03 ± 0.20 vs. 0.32 ± 0.16, respectively; P < 0.05). In the sVlow region, relative perfusion decreased after bronchoconstriction under room air conditions and also, to a lesser degree, under 80% O2 conditions (1.02 ± 0.19 vs. 0.72 ± 0.08 [P < 0.001] and 1.08 ± 0.19 vs. 0.91 ± 0.12 [P < 0.05], respectively). The Fgas increased after bronchoconstriction under room air conditions only (0.99 ± 0.04 vs. 1.00 ± 0.02; P < 0.05). The sVlow subregion analysis indicated that some of the reduction in relative perfusion after bronchoconstriction under 80% O2 conditions occurred as a result of the presence of regional hypoxia. However, relative perfusion was also significantly reduced in sVlow subregions that were hyperoxic under 80% O2 conditions. CONCLUSIONS HPV is not the only mechanism that contributes to perfusion redistribution in bronchoconstricted patients with asthma, suggesting that another nonhypoxia mechanism also contributes. We propose that this nonhypoxia mechanism may be either direct mechanical interactions and/or unidentified intercellular signaling between constricted airways, the parenchyma, and the surrounding vasculature.
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Affiliation(s)
- Vanessa J Kelly
- 1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Kathryn A Hibbert
- 1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Puja Kohli
- 1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Mamary Kone
- 1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
| | - Elliot E Greenblatt
- 2 Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and.,3 Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Jose G Venegas
- 2 Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and
| | - Tilo Winkler
- 2 Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts; and
| | - R Scott Harris
- 1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
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16
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Donovan GM. Inter-airway structural heterogeneity interacts with dynamic heterogeneity to determine lung function and flow patterns in both asthmatic and control simulated lungs. J Theor Biol 2017; 435:98-105. [PMID: 28867222 DOI: 10.1016/j.jtbi.2017.08.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/23/2017] [Accepted: 08/28/2017] [Indexed: 01/10/2023]
Abstract
Asthma is a disease involving both airway remodelling (e.g. thickening of the airway wall) and acute, reversible airway narrowing driven by airway smooth muscle contraction. Both of these processes are known to be heterogeneous, and in this study we consider a new theoretical model which considers the interactions of both mechanisms: structural heterogeneity (variation in airway remodelling) and dynamic heterogeneity (emergent variation in airway narrowing and flow). By integrating both types of inter-airway heterogeneity in a full human lung geometry, we are able to draw several insights regarding the mechanisms underlying observed ventilation heterogeneity. We show that: (1) bimodal ventilation distributions are driven by paradoxical contraction/dilation patterns for airways of all sizes; (2) structural heterogeneity differences between asthmatic and control subjects significantly influences resulting lung function, and observed ventilation heterogeneity patterns; and (3) individual airway dilation probabilities are uncorrelated with prior airway remodelling of that airway.
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Affiliation(s)
- G M Donovan
- Department of Mathematics, University of Auckland, New Zealand.
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17
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Hyperpolarized Gas Magnetic Resonance Lung Imaging in Children and Young Adults. J Thorac Imaging 2017; 31:285-95. [PMID: 27428024 DOI: 10.1097/rti.0000000000000218] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The assessment of early pulmonary disease and its severity can be difficult in young children, as procedures such as spirometry cannot be performed on them. Computed tomography provides detailed structural images of the pulmonary parenchyma, but its major drawback is that the patient is exposed to ionizing radiation. In this context, magnetic resonance imaging (MRI) is a promising technique for the evaluation of pediatric lung disease, especially when serial imaging is needed. Traditionally, MRI played a small role in evaluating the pulmonary parenchyma. Because of its low proton density, the lungs display low signal intensity on conventional proton-based MRI. Hyperpolarized (HP) gases are inhaled contrast agents with an excellent safety profile and provide high signal within the lung, allowing for high temporal and spatial resolution imaging of the lung airspaces. Besides morphologic information, HP MR images also offer valuable information about pulmonary physiology. HP gas MRI has already made new contributions to the understanding of pediatric lung diseases and may become a clinically useful tool. In this article, we discuss the HP gas MRI technique, special considerations that need to be made when imaging children, and the role of MRI in 2 of the most common chronic pediatric lung diseases, asthma and cystic fibrosis. We also will discuss how HP gas MRI may be used to evaluate normal lung growth and development and the alterations occurring in chronic lung disease of prematurity and in patients with a congenital diaphragmatic hernia.
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18
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Sá RC, Zeman KL, Bennett WD, Prisk GK, Darquenne C. Regional Ventilation Is the Main Determinant of Alveolar Deposition of Coarse Particles in the Supine Healthy Human Lung During Tidal Breathing. J Aerosol Med Pulm Drug Deliv 2017; 30:322-331. [PMID: 28277885 DOI: 10.1089/jamp.2016.1336] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND To quantify the relationship between regional lung ventilation and coarse aerosol deposition in the supine healthy human lung, we used oxygen-enhanced magnetic resonance imaging and planar gamma scintigraphy in seven subjects. METHODS Regional ventilation was measured in the supine posture in a 15 mm sagittal slice of the right lung. Deposition was measured by using planar gamma scintigraphy (coronal scans, 40 cm FOV) immediately postdeposition, 1 hour 30 minutes and 22 hours after deposition of 99mTc-labeled particles (4.9 μm MMAD, GSD 2.5), inhaled in the supine posture (flow 0.5 L/s, 15 breaths/min). The distribution of retained particles at different times was used to infer deposition in different airway regions, with 22 hours representing alveolar deposition. The fraction of total slice ventilation per quartile of lung height from the lung apex to the dome of the diaphragm at functional residual capacity was computed, and co-registered with deposition data-apices aligned-using a transmission scan as reference. The ratio of fractional alveolar deposition to fractional ventilation of each quartile (r) was used to evaluate ventilation and deposition matching (r > 1, regional aerosol deposition fraction larger than regional ventilation fraction). RESULTS r was not significantly different from 1 for all regions (1.04 ± 0.25, 1.08 ± 0.22, 1.03 ± 0.17, 0.92 ± 0.13, apex to diaphragm, p > 0.40) at the alveolar level (r22h). For retention times r0h and r1h30, only the diaphragmatic region at r1h30 differed significantly from 1. CONCLUSIONS These results support the hypothesis that alveolar deposition is directly proportional to ventilation for ∼5 μm particles that are inhaled in the supine posture and are consistent with previous simulation predictions that show that convective flow is the main determinant of aerosol transport to the lung periphery.
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Affiliation(s)
- Rui Carlos Sá
- 1 Pulmonary Imaging Laboratory, Department of Medicine, University of California , San Diego, La Jolla, California
| | - Kirby L Zeman
- 2 Department of Medicine, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - William D Bennett
- 2 Department of Medicine, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina
| | - G Kim Prisk
- 1 Pulmonary Imaging Laboratory, Department of Medicine, University of California , San Diego, La Jolla, California.,3 Pulmonary Imaging Laboratory, Department of Radiology, University of California , San Diego, La Jolla, California
| | - Chantal Darquenne
- 1 Pulmonary Imaging Laboratory, Department of Medicine, University of California , San Diego, La Jolla, California
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19
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DeBoer EM, Spielberg DR, Brody AS. Clinical potential for imaging in patients with asthma and other lung disorders. J Allergy Clin Immunol 2016; 139:21-28. [PMID: 27871877 DOI: 10.1016/j.jaci.2016.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/10/2016] [Accepted: 11/10/2016] [Indexed: 12/12/2022]
Abstract
The ability of lung imaging to phenotype patients, determine prognosis, and predict response to treatment is expanding in clinical and translational research. The purpose of this perspective is to describe current imaging modalities that might be useful clinical tools in patients with asthma and other lung disorders and to explore some of the new developments in imaging modalities of the lung. These imaging modalities include chest radiography, computed tomography, lung magnetic resonance imaging, electrical impedance tomography, bronchoscopy, and others.
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Affiliation(s)
- Emily M DeBoer
- University of Colorado Anschutz Medical Campus, Department of Pediatrics, and Breathing Institute, Children's Hospital Colorado, Aurora, Colo.
| | - David R Spielberg
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Alan S Brody
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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