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Klos A, Bailly L, Rolland du Roscoat S, Orgéas L, Henrich Bernardoni N, Broche L, King A. Optimising 4D imaging of fast-oscillating structures using X-ray microtomography with retrospective gating. Sci Rep 2024; 14:20499. [PMID: 39227377 PMCID: PMC11372196 DOI: 10.1038/s41598-024-68684-1] [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: 06/04/2024] [Accepted: 07/26/2024] [Indexed: 09/05/2024] Open
Abstract
Imaging the internal architecture of fast-vibrating structures at micrometer scale and kilohertz frequencies poses great challenges for numerous applications, including the study of biological oscillators, mechanical testing of materials, and process engineering. Over the past decade, X-ray microtomography with retrospective gating has shown very promising advances in meeting these challenges. However, breakthroughs are still expected in acquisition and reconstruction procedures to keep improving the spatiotemporal resolution, and study the mechanics of fast-vibrating multiscale structures. Thereby, this works aims to improve this imaging technique by minimising streaking and motion blur artefacts through the optimisation of experimental parameters. For that purpose, we have coupled a numerical approach relying on tomography simulation with vibrating particles with known and ideal 3D geometry (micro-spheres or fibres) with experimental campaigns. These were carried out on soft composites, imaged in synchrotron X-ray beamlines while oscillating up to 400 Hz, thanks to a custom-developed vibromechanical device. This approach yields homogeneous angular sampling of projections and gives reliable predictions of image quality degradation due to motion blur. By overcoming several technical and scientific barriers limiting the feasibility and reproducibility of such investigations, we provide guidelines to enhance gated-CT 4D imaging for the analysis of heterogeneous, high-frequency oscillating materials.
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Affiliation(s)
- Antoine Klos
- Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, 38000, Grenoble, France
- Univ. Grenoble Alpes, CNRS, Grenoble INP, GIPSA-lab, 38000, Grenoble, France
| | - Lucie Bailly
- Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, 38000, Grenoble, France.
| | | | - Laurent Orgéas
- Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, 38000, Grenoble, France
| | | | - Ludovic Broche
- ID19 beamline, ESRF - The European Synchrotron, CS 40220, 38043, Grenoble, France
| | - Andrew King
- PSICHE beamline, Synchrotron SOLEIL, F-91190, Saint-Aubin, France
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2
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Lagier D, Zeng C, Kaczka DW, Zhu M, Grogg K, Gerard SE, Reinhardt JM, Ribeiro GCM, Rashid A, Winkler T, Vidal Melo MF. Mechanical ventilation guided by driving pressure optimizes local pulmonary biomechanics in an ovine model. Sci Transl Med 2024; 16:eado1097. [PMID: 39141699 DOI: 10.1126/scitranslmed.ado1097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/13/2024] [Accepted: 07/24/2024] [Indexed: 08/16/2024]
Abstract
Mechanical ventilation exposes the lung to injurious stresses and strains that can negatively affect clinical outcomes in acute respiratory distress syndrome or cause pulmonary complications after general anesthesia. Excess global lung strain, estimated as increased respiratory system driving pressure, is associated with mortality related to mechanical ventilation. The role of small-dimension biomechanical factors underlying this association and their spatial heterogeneity within the lung are currently unknown. Using four-dimensional computed tomography with a voxel resolution of 2.4 cubic millimeters and a multiresolution convolutional neural network for whole-lung image segmentation, we dynamically measured voxel-wise lung inflation and tidal parenchymal strains. Healthy or injured ovine lungs were evaluated as the mechanical ventilation positive end-expiratory pressure (PEEP) was titrated from 20 to 2 centimeters of water. The PEEP of minimal driving pressure (PEEPDP) optimized local lung biomechanics. We observed a greater rate of change in nonaerated lung mass with respect to PEEP below PEEPDP compared with PEEP values above this threshold. PEEPDP similarly characterized a breaking point in the relationships between PEEP and SD of local tidal parenchymal strain, the 95th percentile of local strains, and the magnitude of tidal overdistension. These findings advance the understanding of lung collapse, tidal overdistension, and strain heterogeneity as local triggers of ventilator-induced lung injury in large-animal lungs similar to those of humans and could inform the clinical management of mechanical ventilation to improve local lung biomechanics.
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Affiliation(s)
- David Lagier
- Experimental Interventional Imaging Laboratory (LIIE), European Center for Research in Medical Imaging (CERIMED), Aix Marseille University, Marseille 13005, France
- Department of Anesthesia and Critical Care, University Hospital La Timone, APHM, Marseille 13005, France
| | - Congli Zeng
- Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, USA
| | - David W Kaczka
- Departments of Anesthesia and Radiology, University of Iowa, Iowa City, IA 52242, USA
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Min Zhu
- Guizhou University South Campus, Guiyang City 550025, China
| | - Kira Grogg
- Yale PET Center, Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT 06520, USA
| | - Sarah E Gerard
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Joseph M Reinhardt
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Gabriel C Motta Ribeiro
- Biomedical Engineering Program, Alberto Luiz Coimbra Institute for Graduate Studies and Research in Engineering, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-594, Brazil
| | - Azman Rashid
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Tilo Winkler
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Marcos F Vidal Melo
- Department of Anesthesiology, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, USA
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3
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Mago E, Zhao X, Zhang W, Shao Q, Li P, Huang S, Ding X, Liu H, Sun T, He F, Weng D. RIP1 kinase inactivation protects against LPS-induced acute respiratory distress syndrome in mice. Int Immunopharmacol 2024; 133:112060. [PMID: 38652970 DOI: 10.1016/j.intimp.2024.112060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/22/2024] [Accepted: 04/08/2024] [Indexed: 04/25/2024]
Abstract
Acute respiratory distress syndrome (ARDS) is characterized by lung tissue oedema and inflammatory cell infiltration, with limited therapeutic interventions available. Receptor-interacting protein kinase 1 (RIPK1), a critical regulator of cell death and inflammation implicated in many diseases, is not fully understood in the context of ARDS. In this study, we employed RIP1 kinase-inactivated (Rip1K45A/K45A) mice and two distinct RIPK1 inhibitors to investigate the contributions of RIP1 kinase activity in lipopolysaccharide (LPS)-induced ARDS pathology. Our results indicated that RIPK1 kinase inactivation, achieved through both genetic and chemical approaches, significantly attenuated LPS-induced ARDS pathology, as demonstrated by reduced polymorphonuclear neutrophil percentage (PMN%) in alveolar lavage fluid, expression of inflammatory and fibrosis-related factors in lung tissues, as well as histological examination. Results by tunnel staining and qRT-PCR analysis indicated that RIPK1 kinase activity played a role in regulating cell apoptosis and inflammation induced by LPS administration in lung tissue. In summary, employing both pharmacological and genetic approaches, this study demonstrated that targeted RIPK1 kinase inactivation attenuates the pathological phenotype induced by LPS inhalation in an ARDS mouse model. This study enhances our understanding of the therapeutic potential of RIPK1 kinase modulation in ARDS, providing insights for the pathogenesis of ARDS.
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Affiliation(s)
- Emmauel Mago
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Xunan Zhao
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Weigao Zhang
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Qianchao Shao
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Peiqi Li
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Shuxian Huang
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Xinyu Ding
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Hu Liu
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China
| | - Tingzhe Sun
- School of Life Sciences, Anqing Normal University, Anqing 246133, Anhui, China
| | - Fei He
- Department of Emergency Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China.
| | - Dan Weng
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei Street, Nanjing 210094, China.
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4
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Maffezzoni M, Bellini V. Con: Mechanical Ventilation During Cardiopulmonary Bypass. J Cardiothorac Vasc Anesth 2024; 38:1045-1048. [PMID: 38184381 DOI: 10.1053/j.jvca.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 11/28/2023] [Accepted: 12/02/2023] [Indexed: 01/08/2024]
Abstract
The ventilatory strategy to adopt during cardiopulmonary bypass is still being debated. The rationale for using continuous positive airway pressure or mechanical ventilation would be to counteract alveolar collapse and improve ischemia phenomena and passive alveolar diffusion of oxygen. Although there are several studies supporting the hypothesis of a positive effect on oxygenation and systemic inflammatory response, the real clinical impact of ventilation during cardiopulmonary bypass is controversial. Furthermore, the biases present in the literature make the studies' results nonunique in their interpretation.
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Affiliation(s)
- Massimo Maffezzoni
- Anesthesiology, Critical Care and Pain Medicine Division, Department of Medicine and Surgery, University of Parma, Parma, Italy.
| | - Valentina Bellini
- Anesthesiology, Critical Care and Pain Medicine Division, Department of Medicine and Surgery, University of Parma, Parma, Italy
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5
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Katayama S, Tonai K, Nakamura K, Tsuji M, Uchimasu S, Shono A, Sanui M. Can Four-Dimensional Computed Tomography Assess Dynamic Changes in Lung Volumes in Mechanically Ventilated Patients? Am J Respir Crit Care Med 2024; 209:592-595. [PMID: 38029306 DOI: 10.1164/rccm.202309-1659le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 11/29/2023] [Indexed: 12/01/2023] Open
Affiliation(s)
- Shinshu Katayama
- Division of Intensive Care, Department of Anesthesiology and Intensive Care Medicine, School of Medicine, Jichi Medical University, Shimotsuke, Japan; and
| | - Ken Tonai
- Division of Intensive Care, Department of Anesthesiology and Intensive Care Medicine, School of Medicine, Jichi Medical University, Shimotsuke, Japan; and
| | - Kie Nakamura
- Import Business Operations, Nihon Kohden Corporation, Tokorozawa-shi, Japan
| | - Misuzu Tsuji
- Import Business Operations, Nihon Kohden Corporation, Tokorozawa-shi, Japan
| | | | - Atsuko Shono
- Division of Intensive Care, Department of Anesthesiology and Intensive Care Medicine, School of Medicine, Jichi Medical University, Shimotsuke, Japan; and
| | - Masamitsu Sanui
- Division of Intensive Care, Department of Anesthesiology and Intensive Care Medicine, School of Medicine, Jichi Medical University, Shimotsuke, Japan; and
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6
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Fardin L, Giaccaglia C, Busca P, Bravin A. Characterization of a CdTe single-photon-counting detector for biomedical imaging applications. Phys Med 2023; 108:102571. [PMID: 36989977 DOI: 10.1016/j.ejmp.2023.102571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/12/2023] [Accepted: 03/18/2023] [Indexed: 03/29/2023] Open
Abstract
PURPOSE The Eiger 2X CdTe 1 M-W (Dectris ltd, Baden, Switzerland) single photon counting detector was characterized for imaging applications at the biomedical beamline ID17 of the European Synchrotron Radiation Facility. METHODS Linearity, Modulation Transfer Function, Noise Power Spectrum and Detective Quantum Efficiency were measured as a function of photon energy and flux in the range 26-80 keV. RESULTS The linearity was confirmed in the flux range specified by Dectris and a detection efficiency higher than 60 % was measured for energies up to 80 keV. The spatial resolution was inferred from the Modulation Transfer Function and was found to be compatible with the pixel size of the detector (75 μm), except at energies just above the K-edge of Cd and Te where it reached 150 μm. The study of the Noise Power Spectrum showed a time-dependency in the response of the sensor, which is mitigated at low photon fluxes (<2⨯108 ph mm-2 s-1). CONCLUSIONS This work was the first characterization of the Eiger 2X CdTe 1 M-W for imaging applications with monochromatic synchrotron radiation. The spatial resolution and the quantum efficiency are compatible with low-dose imaging applications.
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Albers J, Wagner WL, Fiedler MO, Rothermel A, Wünnemann F, Di Lillo F, Dreossi D, Sodini N, Baratella E, Confalonieri M, Arfelli F, Kalenka A, Lotz J, Biederer J, Wielpütz MO, Kauczor HU, Alves F, Tromba G, Dullin C. High resolution propagation-based lung imaging at clinically relevant X-ray dose levels. Sci Rep 2023; 13:4788. [PMID: 36959233 PMCID: PMC10036329 DOI: 10.1038/s41598-023-30870-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/02/2023] [Indexed: 03/25/2023] Open
Abstract
Absorption-based clinical computed tomography (CT) is the current imaging method of choice in the diagnosis of lung diseases. Many pulmonary diseases are affecting microscopic structures of the lung, such as terminal bronchi, alveolar spaces, sublobular blood vessels or the pulmonary interstitial tissue. As spatial resolution in CT is limited by the clinically acceptable applied X-ray dose, a comprehensive diagnosis of conditions such as interstitial lung disease, idiopathic pulmonary fibrosis or the characterization of small pulmonary nodules is limited and may require additional validation by invasive lung biopsies. Propagation-based imaging (PBI) is a phase sensitive X-ray imaging technique capable of reaching high spatial resolutions at relatively low applied radiation dose levels. In this publication, we present technical refinements of PBI for the characterization of different artificial lung pathologies, mimicking clinically relevant patterns in ventilated fresh porcine lungs in a human-scale chest phantom. The combination of a very large propagation distance of 10.7 m and a photon counting detector with [Formula: see text] pixel size enabled high resolution PBI CT with significantly improved dose efficiency, measured by thermoluminescence detectors. Image quality was directly compared with state-of-the-art clinical CT. PBI with increased propagation distance was found to provide improved image quality at the same or even lower X-ray dose levels than clinical CT. By combining PBI with iodine k-edge subtraction imaging we further demonstrate that, the high quality of the calculated iodine concentration maps might be a potential tool for the analysis of lung perfusion in great detail. Our results indicate PBI to be of great value for accurate diagnosis of lung disease in patients as it allows to depict pathological lesions non-invasively at high resolution in 3D. This will especially benefit patients at high risk of complications from invasive lung biopsies such as in the setting of suspected idiopathic pulmonary fibrosis (IPF).
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Affiliation(s)
- Jonas Albers
- Department for Diagnostic and Interventional Radiology, University Medical Center Goettingen, Goettingen, Germany
- Biological X-ray imaging, European Molecular Biology Laboratory, Hamburg Unit c/o DESY, Hamburg, Germany
| | - Willi L Wagner
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
| | - Mascha O Fiedler
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
- Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Anne Rothermel
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
| | - Felix Wünnemann
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
| | | | - Diego Dreossi
- Elettra-Sincrotrone Trieste S.C.p.A., Trieste, Italy
| | - Nicola Sodini
- Elettra-Sincrotrone Trieste S.C.p.A., Trieste, Italy
| | - Elisa Baratella
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
| | | | - Fulvia Arfelli
- Department of Physics, University of Trieste and INFN, Trieste, Italy
| | - Armin Kalenka
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
- Department of Anaesthesiology and Intensive Care Medicine, District Hospital Bergstrasse, Heppenheim, Germany
- Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Joachim Lotz
- Department for Diagnostic and Interventional Radiology, University Medical Center Goettingen, Goettingen, Germany
| | - Jürgen Biederer
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
- Faculty of Medicine, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Faculty of Medicine, University of Latvia, Riga, Latvia
| | - Mark O Wielpütz
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
| | - Hans-Ulrich Kauczor
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany
| | - Frauke Alves
- Department for Diagnostic and Interventional Radiology, University Medical Center Goettingen, Goettingen, Germany
- Department for Haematology and Medical Oncology, University Medical Center Goettingen, Goettingen, Germany
- Translational Molecular Imaging, Max-Plank-Institute for Multidisciplinary Sciences, Goettingen, Germany
| | | | - Christian Dullin
- Department for Diagnostic and Interventional Radiology, University Medical Center Goettingen, Goettingen, Germany.
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.
- Translational Lung Research Center (TLRC), German Center for Lung Research (DZL), University Heidelberg, Heidelberg, Germany.
- Translational Molecular Imaging, Max-Plank-Institute for Multidisciplinary Sciences, Goettingen, Germany.
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8
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Deep 3D reconstruction of synchrotron X-ray computed tomography for intact lungs. Sci Rep 2023; 13:1738. [PMID: 36720962 PMCID: PMC9889716 DOI: 10.1038/s41598-023-27627-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 01/04/2023] [Indexed: 02/02/2023] Open
Abstract
Synchrotron X-rays can be used to obtain highly detailed images of parts of the lung. However, micro-motion artifacts induced by such as cardiac motion impede quantitative visualization of the alveoli in the lungs. This paper proposes a method that applies a neural network for synchrotron X-ray Computed Tomography (CT) data to reconstruct the high-quality 3D structure of alveoli in intact mouse lungs at expiration, without needing ground-truth data. Our approach reconstructs the spatial sequence of CT images by using a deep-image prior with interpolated input latent variables, and in this way significantly enhances the images of alveolar structure compared with the prior art. The approach successfully visualizes 3D alveolar units of intact mouse lungs at expiration and enables us to measure the diameter of the alveoli. We believe that our approach helps to accurately visualize other living organs hampered by micro-motion.
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Herrmann J, Kollisch-Singule M, Satalin J, Nieman GF, Kaczka DW. Assessment of Heterogeneity in Lung Structure and Function During Mechanical Ventilation: A Review of Methodologies. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2022; 5:040801. [PMID: 35832339 PMCID: PMC9132008 DOI: 10.1115/1.4054386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/13/2022] [Indexed: 06/15/2023]
Abstract
The mammalian lung is characterized by heterogeneity in both its structure and function, by incorporating an asymmetric branching airway tree optimized for maintenance of efficient ventilation, perfusion, and gas exchange. Despite potential benefits of naturally occurring heterogeneity in the lungs, there may also be detrimental effects arising from pathologic processes, which may result in deficiencies in gas transport and exchange. Regardless of etiology, pathologic heterogeneity results in the maldistribution of regional ventilation and perfusion, impairments in gas exchange, and increased work of breathing. In extreme situations, heterogeneity may result in respiratory failure, necessitating support with a mechanical ventilator. This review will present a summary of measurement techniques for assessing and quantifying heterogeneity in respiratory system structure and function during mechanical ventilation. These methods have been grouped according to four broad categories: (1) inverse modeling of heterogeneous mechanical function; (2) capnography and washout techniques to measure heterogeneity of gas transport; (3) measurements of heterogeneous deformation on the surface of the lung; and finally (4) imaging techniques used to observe spatially-distributed ventilation or regional deformation. Each technique varies with regard to spatial and temporal resolution, degrees of invasiveness, risks posed to patients, as well as suitability for clinical implementation. Nonetheless, each technique provides a unique perspective on the manifestations and consequences of mechanical heterogeneity in the diseased lung.
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Affiliation(s)
- Jacob Herrmann
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242
| | | | - Joshua Satalin
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Gary F. Nieman
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY 13210
| | - David W. Kaczka
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242; Department of Anesthesia, University of Iowa, Iowa City, IA 52242; Department of Radiology, University of Iowa, Iowa City, IA 52242
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10
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Aramini B, Masciale V, Samarelli AV, Tonelli R, Cerri S, Clini E, Stella F, Dominici M. Biological effects of COVID-19 on lung cancer: Can we drive our decisions. Front Oncol 2022; 12:1029830. [PMID: 36300087 PMCID: PMC9589049 DOI: 10.3389/fonc.2022.1029830] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 09/23/2022] [Indexed: 11/13/2022] Open
Abstract
COVID-19 infection caused by SARS-CoV-2 is considered catastrophic because it affects multiple organs, particularly those of the respiratory tract. Although the consequences of this infection are not fully clear, it causes damage to the lungs, the cardiovascular and nervous systems, and other organs, subsequently inducing organ failure. In particular, the effects of SARS-CoV-2-induced inflammation on cancer cells and the tumor microenvironment need to be investigated. COVID-19 may alter the tumor microenvironment, promoting cancer cell proliferation and dormant cancer cell (DCC) reawakening. DCCs reawakened upon infection with SARS-CoV-2 can populate the premetastatic niche in the lungs and other organs, leading to tumor dissemination. DCC reawakening and consequent neutrophil and monocyte/macrophage activation with an uncontrolled cascade of pro-inflammatory cytokines are the most severe clinical effects of COVID-19. Moreover, neutrophil extracellular traps have been demonstrated to activate the dissemination of premetastatic cells into the lungs. Further studies are warranted to better define the roles of COVID-19 in inflammation as well as in tumor development and tumor cell metastasis; the results of these studies will aid in the development of further targeted therapies, both for cancer prevention and the treatment of patients with COVID-19.
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Affiliation(s)
- Beatrice Aramini
- Division of Thoracic Surgery, Department of Experimental, Diagnostic and Specialty Medicine—DIMES of the Alma Mater Studiorum, University of Bologna, G.B. Morgagni—L. Pierantoni Hospital, Forlì, Italy
- *Correspondence: Beatrice Aramini,
| | - Valentina Masciale
- Division of Oncology, Department of Medical and Surgical Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Laboratory of Cell Therapy, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena and Reggio Emilia, Modena, Italy
| | - Anna Valeria Samarelli
- Laboratory of Cell Therapy, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena and Reggio Emilia, Modena, Italy
- Respiratory Disease Unit, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena and Reggio Emilia, Modena, Italy
| | - Roberto Tonelli
- Respiratory Disease Unit, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena and Reggio Emilia, Modena, Italy
| | - Stefania Cerri
- Respiratory Disease Unit, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena and Reggio Emilia, Modena, Italy
| | - Enrico Clini
- Respiratory Disease Unit, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena and Reggio Emilia, Modena, Italy
| | - Franco Stella
- Division of Thoracic Surgery, Department of Experimental, Diagnostic and Specialty Medicine—DIMES of the Alma Mater Studiorum, University of Bologna, G.B. Morgagni—L. Pierantoni Hospital, Forlì, Italy
| | - Massimo Dominici
- Division of Oncology, Department of Medical and Surgical Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Laboratory of Cell Therapy, Department of Medical and Surgical Sciences, University Hospital of Modena, University of Modena and Reggio Emilia, Modena, Italy
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11
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Shao RG, Xie QW, Pan LH, Lin F, Qin K, Ming SP, Li JJ, Du XK. Necrostatin-1 attenuates Caspase-1-dependent pyroptosis induced by the RIPK1/ZBP1 pathway in ventilator-induced lung injury. Cytokine 2022; 157:155950. [PMID: 35780712 DOI: 10.1016/j.cyto.2022.155950] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 06/14/2022] [Accepted: 06/18/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Ventilator-induced lung injury (VILI) is a complex pathophysiological process leading to acute respiratory distress syndrome (ARDS) and poor outcomes in affected patients. As a form of programmed cell death, pyroptosis is proposed to play an important role in the development of ARDS. Here we investigated whether treating mice with the specific RIPK1 inhibitor Necrostatin-1 (Nec-1) before mechanical ventilation could inhibit pyroptosis and alleviate lung injury in a mouse model. METHODOLOGYS Anesthetized C57BL/6J mice received a transtracheal injection of Nec-1 (5 mg/kg) or vehicle (DMSO) 30 min before the experiment which was ventilated for up to 4 h. Lung damage was assessed macroscopically and histologically with oedema measured as the wet/dry ratio of lung tissues. The release of inflammatory mediators into bronchoalveolar lavage fluid (BALF) was assessed by ELISA measurements of TNF-α,interleukin-1β (IL-1β), and IL-6. The expression of RIPK1, ZBP1, caspase-1, and activated (cleaved) caspase-1 were analyzed using western blot and immunohistochemistry, and the levels of gasdermin-D (GSDMD) and IL-1β were analyzed by immunofluorescence staining. RESULTS High tidal ventilation produced time-dependent inflammation and lung injury in mice which could be significantly reduced by pretreatment with Nec-1. Notably, Nec-1 reduced the expression of key pyroptosis mediator proteins in lung tissues exposed to mechanical ventilation, including caspase-1, cleaved caspase-1, and GSDMD together with inhibiting the release of inflammatory cytokines. CONCLUSION Nec-1 pretreatment alleviates pulmonary inflammatory responses and protects the lung from mechanical ventilation damage. The beneficial effects were mediated at least in part by inhibiting caspase-1-dependent pyroptosis through the RIPK1/ZBP1 pathway.
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Affiliation(s)
- Rong-Ge Shao
- Department of Anesthesiology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530007, China; Guangxi Clinical Research Center for Anesthesiology, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Engineering Research Center for Tissue & Organ Injury and Repair Medicine, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Key Laboratory for Basic Science and Prevention of Perioperative Organ Disfunction, Guangxi Medical University Cancer Hospital, Nanning 530021, China
| | - Qiu-Wen Xie
- Department of Anesthesiology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530007, China; Guangxi Clinical Research Center for Anesthesiology, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Engineering Research Center for Tissue & Organ Injury and Repair Medicine, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Key Laboratory for Basic Science and Prevention of Perioperative Organ Disfunction, Guangxi Medical University Cancer Hospital, Nanning 530021, China
| | - Ling-Hui Pan
- Guangxi Clinical Research Center for Anesthesiology, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Engineering Research Center for Tissue & Organ Injury and Repair Medicine, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Key Laboratory for Basic Science and Prevention of Perioperative Organ Disfunction, Guangxi Medical University Cancer Hospital, Nanning 530021, China
| | - Fei Lin
- Guangxi Clinical Research Center for Anesthesiology, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Engineering Research Center for Tissue & Organ Injury and Repair Medicine, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Key Laboratory for Basic Science and Prevention of Perioperative Organ Disfunction, Guangxi Medical University Cancer Hospital, Nanning 530021, China
| | - Ke Qin
- Department of Anesthesiology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530007, China
| | - Shao-Peng Ming
- Department of Anesthesiology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530007, China
| | - Jin-Ju Li
- Department of Anesthesiology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530007, China; Guangxi Clinical Research Center for Anesthesiology, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Engineering Research Center for Tissue & Organ Injury and Repair Medicine, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Key Laboratory for Basic Science and Prevention of Perioperative Organ Disfunction, Guangxi Medical University Cancer Hospital, Nanning 530021, China
| | - Xue-Ke Du
- Department of Anesthesiology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530007, China; Guangxi Clinical Research Center for Anesthesiology, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Engineering Research Center for Tissue & Organ Injury and Repair Medicine, Guangxi Medical University Cancer Hospital, Nanning 530021, China; Guangxi Key Laboratory for Basic Science and Prevention of Perioperative Organ Disfunction, Guangxi Medical University Cancer Hospital, Nanning 530021, China.
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12
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Neelakantan S, Xin Y, Gaver DP, Cereda M, Rizi R, Smith BJ, Avazmohammadi R. Computational lung modelling in respiratory medicine. J R Soc Interface 2022; 19:20220062. [PMID: 35673857 PMCID: PMC9174712 DOI: 10.1098/rsif.2022.0062] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/03/2022] [Indexed: 11/12/2022] Open
Abstract
Computational modelling of the lungs is an active field of study that integrates computational advances with lung biophysics, biomechanics, physiology and medical imaging to promote individualized diagnosis, prognosis and therapy evaluation in lung diseases. The complex and hierarchical architecture of the lung offers a rich, but also challenging, research area demanding a cross-scale understanding of lung mechanics and advanced computational tools to effectively model lung biomechanics in both health and disease. Various approaches have been proposed to study different aspects of respiration, ranging from compartmental to discrete micromechanical and continuum representations of the lungs. This article reviews several developments in computational lung modelling and how they are integrated with preclinical and clinical data. We begin with a description of lung anatomy and how different tissue components across multiple length scales affect lung mechanics at the organ level. We then review common physiological and imaging data acquisition methods used to inform modelling efforts. Building on these reviews, we next present a selection of model-based paradigms that integrate data acquisitions with modelling to understand, simulate and predict lung dynamics in health and disease. Finally, we highlight possible future directions where computational modelling can improve our understanding of the structure-function relationship in the lung.
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Affiliation(s)
- Sunder Neelakantan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Yi Xin
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Donald P. Gaver
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahim Rizi
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Bradford J. Smith
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatric Pulmonary and Sleep Medicine, School of Medicine, University of Colorado, Aurora, CO, USA
| | - Reza Avazmohammadi
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
- Department of Cardiovascular Sciences, Houston Methodist Academic Institute, Houston, TX, USA
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13
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Bayat S, Fardin L, Cercos-Pita JL, Perchiazzi G, Bravin A. Imaging Regional Lung Structure and Function in Small Animals Using Synchrotron Radiation Phase-Contrast and K-Edge Subtraction Computed Tomography. Front Physiol 2022; 13:825433. [PMID: 35350681 PMCID: PMC8957951 DOI: 10.3389/fphys.2022.825433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Synchrotron radiation offers unique properties of coherence, utilized in phase-contrast imaging, and high flux as well as a wide energy spectrum which allow the selection of very narrow energy bands of radiation, used in K-edge subtraction imaging (KES) imaging. These properties extend X-ray computed tomography (CT) capabilities to quantitatively assess lung morphology, and to map regional lung ventilation, perfusion, inflammation, aerosol particle distribution and biomechanical properties, with microscopic spatial resolution. Four-dimensional imaging, allows the investigation of the dynamics of regional lung functional parameters simultaneously with structural deformation of the lung as a function of time. These techniques have proven to be very useful for revealing the regional differences in both lung structure and function which is crucial for better understanding of disease mechanisms as well as for evaluating treatment in small animal models of lung diseases. Here, synchrotron radiation imaging methods are described and examples of their application to the study of disease mechanisms in preclinical animal models are presented.
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Affiliation(s)
- Sam Bayat
- Univ. Grenoble Alpes, Inserm UA07 STROBE Laboratory, University of Grenoble Alpes, Grenoble, France.,Department of Pulmonology and Clinical Physiology, Grenoble University Hospital, Grenoble, France
| | - Luca Fardin
- European Synchrotron Radiation Facility, Grenoble, France
| | - José Luis Cercos-Pita
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Gaetano Perchiazzi
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Alberto Bravin
- Department of Physics, University of Milano-Bicocca, Milan, Italy
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14
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Cercos-Pita JL, Fardin L, Leclerc H, Maury B, Perchiazzi G, Bravin A, Bayat S. Lung tissue biomechanics imaged with synchrotron phase contrast microtomography in live rats. Sci Rep 2022; 12:5056. [PMID: 35322152 PMCID: PMC8942151 DOI: 10.1038/s41598-022-09052-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/09/2022] [Indexed: 12/19/2022] Open
Abstract
The magnitude and distribution of strain imposed on the peripheral airspaces by mechanical ventilation at the microscopic level and the consequent deformations are unknown despite their importance for understanding the mechanisms occurring at the onset of ventilator-induced lung injury. Here a 4-Dimensional (3D + time) image acquisition and processing technique is developed to assess pulmonary acinar biomechanics at microscopic resolution. Synchrotron radiation phase contrast CT with an isotropic voxel size of 6 µm3 is applied in live anesthetized rats under controlled mechanical ventilation. Video animations of regional acinar and vascular strain are acquired in vivo. Maps of strain distribution due to positive-pressure breaths and cardiovascular activity in lung acini and blood vessels are derived based on CT images. Regional strain within the lung peripheral airspaces takes average values of 0.09 ± 0.02. Fitting the expression S = kVn, to the changes in peripheral airspace area (S) and volume (V) during a positive pressure breath yields an exponent n = 0.82 ± 0.03, suggesting predominant alveolar expansion rather than ductal expansion or alveolar recruitment. We conclude that this methodology can be used to assess acinar conformational changes during positive pressure breaths in intact peripheral lung airspaces.
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Affiliation(s)
- Jose-Luis Cercos-Pita
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Luca Fardin
- European Synchrotron Radiation Facility, Grenoble, France
| | - Hugo Leclerc
- Laboratoire de Mathématiques d'Orsay, Université Paris-Saclay, Orsay, France
| | - Bertrand Maury
- Département de Mathématiques Appliquées, Ecole Normale Supérieure, Université PSL, Paris, France
| | - Gaetano Perchiazzi
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Alberto Bravin
- Physics Department, Milano Bicocca University, Milan, Italy
| | - Sam Bayat
- Synchrotron Radiation for Biomedicine STROBE Inserm UA07, Univ. Grenoble Alpes, Grenoble, France.
- Univ. Grenoble Alpes - Inserm UA07, Synchrotron Radiation for Biomedicine (STROBE) Laboratory, 2280 Rue de la Piscine, 38400, Grenoble, France.
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15
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Romano M, Bravin DA, Wright DMD, Jacques L, Miettinen DA, Hlushchuk DR, Dinkel J, Bartzsch DS, Laissue JA, Djonov V, Coan DP. X-ray Phase Contrast 3D virtual histology: evaluation of lung alterations after micro-beam irradiation. Int J Radiat Oncol Biol Phys 2021; 112:818-830. [PMID: 34678432 DOI: 10.1016/j.ijrobp.2021.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 09/20/2021] [Accepted: 10/05/2021] [Indexed: 12/24/2022]
Abstract
PURPOSE This study provides the first experimental application of multiscale three-dimensional (3D) X-ray Phase Contrast Imaging Computed Tomography (XPCI-CT) virtual histology for the inspection and quantitative assessment of the late stage effects of radio-induced lesions on lungs in a small animal model. METHODS AND MATERIALS Healthy male Fischer rats were irradiated with X-ray standard broad beams and Microbeam Radiation Therapy (MRT), a high dose rate (14 kGy/s), FLASH spatially-fractionated X-ray therapy to avoid the beamlets smearing due to cardiosynchronous movements of the organs during the irradiation. After organ dissection, ex-vivo XPCI-CT was applied to all the samples and the results were quantitatively analysed and correlated to histologic data. RESULTS XPCI-CT enables the 3D visualization of lung tissues with unprecedented contrast and sensitivity allowing alveoli, vessels and bronchi hierarchical visualization. XPCI-CT discriminates in 3D radio-induced lesions such as fibrotic scars, Ca/Fe deposits and, in addition, allows a full-organ accurate quantification of the fibrotic tissue within the irradiated organs. The radiation-induced fibrotic tissue content is less than 10% of the analyzed volume for all the MRT treated organs while it reaches the 34% in the case of irradiations with 50 Gy using a broad beam. CONCLUSIONS XPCI-CT is an effective imaging technique able to provide detailed 3D information for the assessment of lung pathology and treatment efficacy in a small animal model.
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Affiliation(s)
- Mariele Romano
- Faculty of Physics, Ludwig Maximilian University, Am Coulombwall 1, München, Garching, Germany
| | - Dr Alberto Bravin
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, France, 38000
| | | | - Laurent Jacques
- Faculty of Physics, Ludwig Maximilian University, Am Coulombwall 1, München, Garching, Germany
| | - Dr Arttu Miettinen
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland
| | - Dr Ruslan Hlushchuk
- Institute of Anatomy, University of Bern, 2 Baltzerstrasse, Bern, Switzerland Department
| | - Julien Dinkel
- Department of Clinical Radiology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Dr Stefan Bartzsch
- Department of Radiation Oncology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany; Helmholtz Centre Munich, Institute for Radiation Medicine, Munich, Germany
| | - Jean Albert Laissue
- Institute of Anatomy, University of Bern, 2 Baltzerstrasse, Bern, Switzerland Department
| | - Valentin Djonov
- Institute of Anatomy, University of Bern, 2 Baltzerstrasse, Bern, Switzerland Department
| | - Dr Paola Coan
- Faculty of Physics, Ludwig Maximilian University, Am Coulombwall 1, München, Garching, Germany; Department of Clinical Radiology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
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16
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Herrmann J, Gerard SE, Shao W, Xin Y, Cereda M, Reinhardt JM, Christensen GE, Hoffman EA, Kaczka DW. Effects of Lung Injury on Regional Aeration and Expiratory Time Constants: Insights From Four-Dimensional Computed Tomography Image Registration. Front Physiol 2021; 12:707119. [PMID: 34393824 PMCID: PMC8355819 DOI: 10.3389/fphys.2021.707119] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 06/30/2021] [Indexed: 11/13/2022] Open
Abstract
Rationale: Intratidal changes in regional lung aeration, as assessed with dynamic four-dimensional computed tomography (CT; 4DCT), may indicate the processes of recruitment and derecruitment, thus portending atelectrauma during mechanical ventilation. In this study, we characterized the time constants associated with deaeration during the expiratory phase of pressure-controlled ventilation in pigs before and after acute lung injury using respiratory-gated 4DCT and image registration. Methods: Eleven pigs were mechanically ventilated in pressure-controlled mode under baseline conditions and following an oleic acid model of acute lung injury. Dynamic 4DCT scans were acquired without interrupting ventilation. Automated segmentation of lung parenchyma was obtained by a convolutional neural network. Respiratory structures were aligned using 4D image registration. Exponential regression was performed on the time-varying CT density in each aligned voxel during exhalation, resulting in regional estimates of intratidal aeration change and deaeration time constants. Regressions were also performed for regional and total exhaled gas volume changes. Results: Normally and poorly aerated lung regions demonstrated the largest median intratidal aeration changes during exhalation, compared to minimal changes within hyper- and non-aerated regions. Following lung injury, median time constants throughout normally aerated regions within each subject were greater than respective values for poorly aerated regions. However, parametric response mapping revealed an association between larger intratidal aeration changes and slower time constants. Lower aeration and faster time constants were observed for the dependent lung regions in the supine position. Regional gas volume changes exhibited faster time constants compared to regional density time constants, as well as better correspondence to total exhaled volume time constants. Conclusion: Mechanical time constants based on exhaled gas volume underestimate regional aeration time constants. After lung injury, poorly aerated regions experience larger intratidal changes in aeration over shorter time scales compared to normally aerated regions. However, the largest intratidal aeration changes occur over the longest time scales within poorly aerated regions. These dynamic 4DCT imaging data provide supporting evidence for the susceptibility of poorly aerated regions to ventilator-induced lung injury, and for the functional benefits of short exhalation times during mechanical ventilation of injured lungs.
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Affiliation(s)
- Jacob Herrmann
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Sarah E Gerard
- Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Wei Shao
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States
| | - Joseph M Reinhardt
- Department of Radiology, University of Iowa, Iowa City, IA, United States.,Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States
| | - Gary E Christensen
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA, United States.,Department of Radiation Oncology, University of Iowa, Iowa City, IA, United States
| | - Eric A Hoffman
- Department of Radiology, University of Iowa, Iowa City, IA, United States.,Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States.,Department of Internal Medicine, University of Iowa, Iowa City, IA, United States
| | - David W Kaczka
- Department of Radiology, University of Iowa, Iowa City, IA, United States.,Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States.,Department of Anesthesia, University of Iowa, Iowa City, IA, United States
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