1
|
Kuo WC, Kao MC, Ting CK, Teng WN. Optical Coherence Tomography Needle Probe in Neuraxial Block Application. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 2021; 27:1-6. [DOI: 10.1109/jstqe.2020.3042076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Wen-Chuan Kuo
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Meng-Chun Kao
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Chien-Kun Ting
- Department of Anesthesiology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | - Wei-Nung Teng
- Department of Anesthesiology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| |
Collapse
|
2
|
Grune J, Tabuchi A, Kuebler WM. Alveolar dynamics during mechanical ventilation in the healthy and injured lung. Intensive Care Med Exp 2019; 7:34. [PMID: 31346797 PMCID: PMC6658629 DOI: 10.1186/s40635-019-0226-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 02/13/2019] [Indexed: 02/12/2023] Open
Abstract
Mechanical ventilation is a life-saving therapy in patients with acute respiratory distress syndrome (ARDS). However, mechanical ventilation itself causes severe co-morbidities in that it can trigger ventilator-associated lung injury (VALI) in humans or ventilator-induced lung injury (VILI) in experimental animal models. Therefore, optimization of ventilation strategies is paramount for the effective therapy of critical care patients. A major problem in the stratification of critical care patients for personalized ventilation settings, but even more so for our overall understanding of VILI, lies in our limited insight into the effects of mechanical ventilation at the actual site of injury, i.e., the alveolar unit. Unfortunately, global lung mechanics provide for a poor surrogate of alveolar dynamics and methods for the in-depth analysis of alveolar dynamics on the level of individual alveoli are sparse and afflicted by important limitations. With alveolar dynamics in the intact lung remaining largely a "black box," our insight into the mechanisms of VALI and VILI and the effectiveness of optimized ventilation strategies is confined to indirect parameters and endpoints of lung injury and mortality.In the present review, we discuss emerging concepts of alveolar dynamics including alveolar expansion/contraction, stability/instability, and opening/collapse. Many of these concepts remain still controversial, in part due to limitations of the different methodologies applied. We therefore preface our review with an overview of existing technologies and approaches for the analysis of alveolar dynamics, highlighting their individual strengths and limitations which may provide for a better appreciation of the sometimes diverging findings and interpretations. Joint efforts combining key technologies in identical models to overcome the limitations inherent to individual methodologies are needed not only to provide conclusive insights into lung physiology and alveolar dynamics, but ultimately to guide critical care patient therapy.
Collapse
Affiliation(s)
- Jana Grune
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, 10117 Berlin, Germany
| | - Arata Tabuchi
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Wolfgang M. Kuebler
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, 10117 Berlin, Germany
- The Keenan Research Centre for Biomedical Science at St. Michael’s, Toronto, Canada
- Departments of Surgery and Physiology, University of Toronto, Toronto, Canada
| |
Collapse
|
3
|
Vanherp L, Poelmans J, Hillen A, Govaerts K, Belderbos S, Buelens T, Lagrou K, Himmelreich U, Vande Velde G. Bronchoscopic fibered confocal fluorescence microscopy for longitudinal in vivo assessment of pulmonary fungal infections in free-breathing mice. Sci Rep 2018; 8:3009. [PMID: 29445211 PMCID: PMC5813038 DOI: 10.1038/s41598-018-20545-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 01/21/2018] [Indexed: 11/12/2022] Open
Abstract
Respiratory diseases, such as pulmonary infections, are an important cause of morbidity and mortality worldwide. Preclinical studies often require invasive techniques to evaluate the extent of infection. Fibered confocal fluorescence microscopy (FCFM) is an emerging optical imaging technique that allows for real-time detection of fluorescently labeled cells within live animals, thereby bridging the gap between in vivo whole-body imaging methods and traditional histological examinations. Previously, the use of FCFM in preclinical lung research was limited to endpoint observations due to the invasive procedures required to access lungs. Here, we introduce a bronchoscopic FCFM approach that enabled in vivo visualization and morphological characterisation of fungal cells within lungs of mice suffering from pulmonary Aspergillus or Cryptococcus infections. The minimally invasive character of this approach allowed longitudinal monitoring of infection in free-breathing animals, thereby providing both visual and quantitative information on infection progression. Both the sensitivity and specificity of this technique were high during advanced stages of infection, allowing clear distinction between infected and non-infected animals. In conclusion, our study demonstrates the potential of this novel bronchoscopic FCFM approach to study pulmonary diseases, which can lead to novel insights in disease pathogenesis by allowing longitudinal in vivo microscopic examinations of the lungs.
Collapse
Affiliation(s)
- Liesbeth Vanherp
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium
| | - Jennifer Poelmans
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium
| | - Amy Hillen
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium
| | - Kristof Govaerts
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium
| | - Sarah Belderbos
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium
| | - Tinne Buelens
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium
| | - Katrien Lagrou
- Laboratory of Clinical Bacteriology and Mycology, Department of Microbiology and Immunology, KU Leuven, Herestraat 49 box 6711, 3000, Leuven, Belgium
| | - Uwe Himmelreich
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium
| | - Greetje Vande Velde
- Biomedical MRI unit/MoSAIC, Department of Imaging and Pathology, KU Leuven, Herestraat 49 O & N1 box 505, 3000, Leuven, Belgium.
| |
Collapse
|
4
|
Abstract
INTRODUCTION The field of interventional pulmonology (IP) is a rapidly maturing subspecialty of pulmonary medicine, which emphasizes advanced diagnostic and therapeutic bronchoscopy for the evaluation and management of central airway obstruction, mediastinal/hilar adenopathy and lung nodules/masses, as well as minimally invasive diagnostic and therapeutic pleural procedures. Areas covered: This review describes advances in diagnostic and therapeutic bronchoscopic techniques. Expert commentary: In the past decade, there has been a remarkable growth in available technology and equipment, as well as clinical and translational research efforts focused on patient-centered outcomes. Furthermore, the recent establishment of a uniform accreditation standard for all IP fellowship programs in the United States was an important step in the continued evolution of this subspecialty of pulmonary medicine.
Collapse
Affiliation(s)
- Diana H Yu
- a School of Medicine, Division of Pulmonary/Critical Care Medicine, Section of Interventional Pulmonology , Johns Hopkins University , Baltimore , USA
| | - David Feller-Kopman
- a School of Medicine, Division of Pulmonary/Critical Care Medicine, Section of Interventional Pulmonology , Johns Hopkins University , Baltimore , USA
| |
Collapse
|
5
|
Aulakh GK. Neutrophils in the lung: “the first responders”. Cell Tissue Res 2017; 371:577-588. [DOI: 10.1007/s00441-017-2748-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 11/21/2017] [Indexed: 12/27/2022]
|
6
|
Aulakh GK, Mann A, Belev G, Wiebe S, Kuebler WM, Singh B, Chapman D. Multiple image x-radiography for functional lung imaging. Phys Med Biol 2017; 63:015009. [PMID: 29116051 DOI: 10.1088/1361-6560/aa9904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Detection and visualization of lung tissue structures is impaired by predominance of air. However, by using synchrotron x-rays, refraction of x-rays at the interface of tissue and air can be utilized to generate contrast which may in turn enable quantification of lung optical properties. We utilized multiple image radiography, a variant of diffraction enhanced imaging, at the Canadian light source to quantify changes in unique x-ray optical properties of lungs, namely attenuation, refraction and ultra small-angle scatter (USAXS or width) contrast ratios as a function of lung orientation in free-breathing or respiratory-gated mice before and after intra-nasal bacterial endotoxin (lipopolysaccharide) instillation. The lung ultra small-angle scatter and attenuation contrast ratios were significantly higher 9 h post lipopolysaccharide instillation compared to saline treatment whereas the refraction contrast decreased in magnitude. In ventilated mice, end-expiratory pressures result in an increase in ultra small-angle scatter contrast ratio when compared to end-inspiratory pressures. There were no detectable changes in lung attenuation or refraction contrast ratio with change in lung pressure alone. In effect, multiple image radiography can be applied towards following optical properties of lung air-tissue barrier over time during pathologies such as acute lung injury.
Collapse
Affiliation(s)
- G K Aulakh
- Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | | | | | | | | | | | | |
Collapse
|
7
|
Real-time in-vivo imaging of pulmonary capillary perfusion using probe-based confocal laser scanning endomicroscopy in pigs. Eur J Anaesthesiol 2015; 32:392-9. [DOI: 10.1097/eja.0000000000000260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
8
|
McLaughlin RA, Noble PB, Sampson DD. Optical coherence tomography in respiratory science and medicine: from airways to alveoli. Physiology (Bethesda) 2015; 29:369-80. [PMID: 25180266 DOI: 10.1152/physiol.00002.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Optical coherence tomography is a rapidly maturing optical imaging technology, enabling study of the in vivo structure of lung tissue at a scale of tens of micrometers. It has been used to assess the layered structure of airway walls, quantify both airway lumen caliber and compliance, and image individual alveoli. This article provides an overview of the technology and reviews its capability to provide new insights into respiratory disease.
Collapse
Affiliation(s)
- Robert A McLaughlin
- Optical & Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Australia;
| | - Peter B Noble
- School of Anatomy, Physiology & Human Biology, and Centre for Neonatal Research & Education, School of Paediatrics and Child Health, The University of Western Australia, Crawley, Australia; and
| | - David D Sampson
- Optical & Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Perth, Australia; Centre for Microscopy, Characterisation & Analysis, The University of Western Australia, Perth, Australia
| |
Collapse
|
9
|
Namati E, Warger WC, Unglert CI, Eckert JE, Hostens J, Bouma BE, Tearney GJ. Four-dimensional visualization of subpleural alveolar dynamics in vivo during uninterrupted mechanical ventilation of living swine. BIOMEDICAL OPTICS EXPRESS 2013; 4:2492-506. [PMID: 24298409 PMCID: PMC3829543 DOI: 10.1364/boe.4.002492] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/24/2013] [Accepted: 08/28/2013] [Indexed: 05/04/2023]
Abstract
Pulmonary alveoli have been studied for many years, yet no unifying hypothesis exists for their dynamic mechanics during respiration due to their miniature size (100-300 μm dimater in humans) and constant motion, which prevent standard imaging techniques from visualizing four-dimensional dynamics of individual alveoli in vivo. Here we report a new platform to image the first layer of air-filled subpleural alveoli through the use of a lightweight optical frequency domain imaging (OFDI) probe that can be placed upon the pleura to move with the lung over the complete range of respiratory motion. This device enables in-vivo acquisition of four-dimensional microscopic images of alveolar airspaces (alveoli and ducts), within the same field of view, during continuous ventilation without restricting the motion or modifying the structure of the alveoli. Results from an exploratory study including three live swine suggest that subpleural alveolar air spaces are best fit with a uniform expansion (r (2) = 0.98) over a recruitment model (r (2) = 0.72). Simultaneously, however, the percentage change in volume shows heterogeneous alveolar expansion within just a 1 mm x 1 mm field of view. These results signify the importance of four-dimensional imaging tools, such as the device presented here. Quantification of the dynamic response of the lung during ventilation may help create more accurate modeling techniques and move toward a more complete understanding of alveolar mechanics.
Collapse
Affiliation(s)
- Eman Namati
- Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Blossom St., BAR-714, Boston, MA 02114 USA
- Co-first authors. These authors contributed equally to this work
| | - William C. Warger
- Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Blossom St., BAR-714, Boston, MA 02114 USA
- Co-first authors. These authors contributed equally to this work
| | - Carolin I. Unglert
- Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Blossom St., BAR-714, Boston, MA 02114 USA
- Air Liquide Centre de Recherche Claude-Delorme, Medical Gases Group, 1 Chemin de la Porte des Loges, Les-Loges-en-Josas, France
| | - Jocelyn E. Eckert
- Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Blossom St., BAR-714, Boston, MA 02114 USA
| | | | - Brett E. Bouma
- Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Blossom St., BAR-714, Boston, MA 02114 USA
- Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Guillermo J. Tearney
- Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Blossom St., BAR-714, Boston, MA 02114 USA
- Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114 USA
| |
Collapse
|
10
|
Pagnozzi AM, Kirk RW, Kennedy BF, Sampson DD, McLaughlin RA. Automated quantification of lung structures from optical coherence tomography images. BIOMEDICAL OPTICS EXPRESS 2013; 4:2383-2395. [PMID: 24298402 PMCID: PMC3829535 DOI: 10.1364/boe.4.002383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/24/2013] [Accepted: 09/26/2013] [Indexed: 05/30/2023]
Abstract
Characterization of the size of lung structures can aid in the assessment of a range of respiratory diseases. In this paper, we present a fully automated segmentation and quantification algorithm for the delineation of large numbers of lung structures in optical coherence tomography images, and the characterization of their size using the stereological measure of median chord length. We demonstrate this algorithm on scans acquired with OCT needle probes in fresh, ex vivo tissues from two healthy animal models: pig and rat. Automatically computed estimates of lung structure size were validated against manual measures. In addition, we present 3D visualizations of the lung structures using the segmentation calculated for each data set. This method has the potential to provide an in vivo indicator of structural remodeling caused by a range of respiratory diseases, including chronic obstructive pulmonary disease and pulmonary fibrosis.
Collapse
Affiliation(s)
- Alex M. Pagnozzi
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Rodney W. Kirk
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Brendan F. Kennedy
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - David D. Sampson
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - Robert A. McLaughlin
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| |
Collapse
|
11
|
Cyclic recruitment of atelectasis – Are there implications for our clinical practice? TRENDS IN ANAESTHESIA AND CRITICAL CARE 2013. [DOI: 10.1016/j.tacc.2013.02.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
12
|
Endoscopic Imaging to Assess Alveolar Mechanics During Quasi-static and Dynamic Ventilatory Conditions in Rats With Noninjured and Injured Lungs*. Crit Care Med 2013; 41:1286-95. [DOI: 10.1097/ccm.0b013e31827712fa] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
13
|
Hanna G, Fontanella A, Palmer G, Shan S, Radiloff DR, Zhao Y, Irwin D, Hamilton K, Boico A, Piantadosi CA, Blueschke G, Dewhirst M, McMahon T, Schroeder T. Automated measurement of blood flow velocity and direction and hemoglobin oxygen saturation in the rat lung using intravital microscopy. Am J Physiol Lung Cell Mol Physiol 2013; 304:L86-91. [PMID: 23161885 PMCID: PMC9762732 DOI: 10.1152/ajplung.00178.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Intravital microscopy of the pulmonary microcirculation in research animals is of great scientific interest for its utility in identifying regional changes in pulmonary microcirculatory blood flow. Although feasibility studies have been reported, the pulmonary window can be further refined into a practical tool for pharmaceutical research and drug development. We have established a method to visualize and quantify dynamic changes in three key features of lung function: microvascular red blood cell velocity, flow direction, and hemoglobin saturation. These physiological parameters were measured in an acute closed-chest pulmonary window, which allows real-time images to be captured by fluorescence and multispectral absorption microscopy; images were subsequently quantified using computerized analysis. We validated the model by quantifying changes in microcirculatory blood flow and hemoglobin saturation in two ways: 1) after changes in inspired oxygen content and 2) after pharmacological reduction of pulmonary blood flow via treatment with the β1 adrenergic receptor blocker metoprolol. This robust and relatively simple system facilitates pulmonary intravital microscopy in laboratory rats for pharmacological and physiological research.
Collapse
Affiliation(s)
- Gabi Hanna
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Andrew Fontanella
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Gregory Palmer
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Siqing Shan
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Daniel R. Radiloff
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Yulin Zhao
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - David Irwin
- 3Department of Cardiology, University of Colorado Denver, Denver, Colorado
| | - Karyn Hamilton
- 4Department of Health and Exercise Sciences, Colorado State University, Fort Collins, Colorado
| | - Alina Boico
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Claude A. Piantadosi
- 5Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - Gert Blueschke
- 6Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Mark Dewhirst
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Timothy McMahon
- 2Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Thies Schroeder
- 1Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| |
Collapse
|
14
|
Unglert CI, Warger WC, Hostens J, Namati E, Birngruber R, Bouma BE, Tearney GJ. Validation of two-dimensional and three-dimensional measurements of subpleural alveolar size parameters by optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:126015. [PMID: 23235834 PMCID: PMC3519489 DOI: 10.1117/1.jbo.17.12.126015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Optical coherence tomography (OCT) has been increasingly used for imaging pulmonary alveoli. Only a few studies, however, have quantified individual alveolar areas, and the validity of alveolar volumes represented within OCT images has not been shown. To validate quantitative measurements of alveoli from OCT images, we compared the cross-sectional area, perimeter, volume, and surface area of matched subpleural alveoli from microcomputed tomography (micro-CT) and OCT images of fixed air-filled swine samples. The relative change in size between different alveoli was extremely well correlated (r>0.9, P<0.0001), but OCT images underestimated absolute sizes compared to micro-CT by 27% (area), 7% (perimeter), 46% (volume), and 25% (surface area) on average. We hypothesized that the differences resulted from refraction at the tissue-air interfaces and developed a ray-tracing model that approximates the reconstructed alveolar size within OCT images. Using this model and OCT measurements of the refractive index for lung tissue (1.41 for fresh, 1.53 for fixed), we derived equations to obtain absolute size measurements of superellipse and circular alveoli with the use of predictive correction factors. These methods and results should enable the quantification of alveolar sizes from OCT images in vivo.
Collapse
Affiliation(s)
- Carolin I Unglert
- Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, 40 Parkman Street, RSL 160, Boston, Massachusetts 02114, USA.
| | | | | | | | | | | | | |
Collapse
|
15
|
McLaughlin RA, Yang X, Quirk BC, Lorenser D, Kirk RW, Noble PB, Sampson DD. Static and dynamic imaging of alveoli using optical coherence tomography needle probes. J Appl Physiol (1985) 2012; 113:967-74. [DOI: 10.1152/japplphysiol.00051.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Imaging of alveoli in situ has for the most part been infeasible due to the high resolution required to discern individual alveoli and limited access to alveoli beneath the lung surface. In this study, we present a novel technique to image alveoli using optical coherence tomography (OCT). We propose the use of OCT needle probes, where the distal imaging probe has been miniaturized and encased within a hypodermic needle (as small as 30-gauge, outer diameter 310 μm), allowing insertion deep within the lung tissue with minimal tissue distortion. Such probes enable imaging at a resolution of ∼12 μm within a three-dimensional cylindrical field of view with diameter ∼1.5 mm centered on the needle tip. The imaging technique is demonstrated on excised lungs from three different species: adult rats, fetal sheep, and adult pigs. OCT needle probes were used to image alveoli, small bronchioles, and blood vessels, and results were matched to histological sections. We also present the first dynamic OCT images acquired with an OCT needle probe, allowing tracking of individual alveoli during simulated cyclical lung inflation and deflation.
Collapse
Affiliation(s)
- Robert A. McLaughlin
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Xiaojie Yang
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Bryden C. Quirk
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Dirk Lorenser
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Rodney W. Kirk
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
| | - Peter B. Noble
- Centre for Neonatal Research and Education, School of Women's and Infants' Health, University of Western Australia, Crawley, Western Australia, Australia; and
| | - David D. Sampson
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley Western Australia, Australia
| |
Collapse
|
16
|
Czaplik M, Biener I, Dembinski R, Pelosi P, Soodt T, Schroeder W, Leonhardt S, Marx G, Rossaint R, Bickenbach J. Analysis of regional compliance in a porcine model of acute lung injury. Respir Physiol Neurobiol 2012; 184:16-26. [PMID: 22820182 DOI: 10.1016/j.resp.2012.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/11/2012] [Accepted: 07/12/2012] [Indexed: 11/25/2022]
Abstract
Lung protective ventilation in acute lung injury (ALI) focuses on using low tidal volumes and adequate levels of positive end-expiratory pressure (PEEP). Identifying optimal pressure is difficult because pressure-volume (PV) relations differ regionally. Precise analysis demands local measurements of pressures and related alveolar morphologies. In a porcine model of surfactant depletion (n=24), we combined measuring static pressures with endoscopic microscopy and electrical impedance tomography (EIT) to examine regional PV loops and morphologic heterogeneities between healthy (control group; CON) and ALI lungs ventilated with low (LVT) or high tidal volumes (HVT). Quantification included indices for microscopy (Volume Air Index (VAI), Heterogeneity and Circularity Index), EIT analysis and calculation of regional compliances due to generated PV loops. We found that: (1) VAI decreased in lower lobe after ALI, (2) electrical impedance decreased in dorsal regions and (3) PV loops differed regionally. Further studies should prove the potentials of these techniques on individual respiratory settings and clinical outcome.
Collapse
Affiliation(s)
- Michael Czaplik
- Department of Anesthesiology, University Hospital RWTH, Aachen, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Klyen BR, Shavlakadze T, Radley-Crabb HG, Grounds MD, Sampson DD. Identification of muscle necrosis in the mdx mouse model of Duchenne muscular dystrophy using three-dimensional optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:076013. [PMID: 21806274 DOI: 10.1117/1.3598842] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Three-dimensional optical coherence tomography (3D-OCT) was used to image the structure and pathology of skeletal muscle tissue from the treadmill-exercised mdx mouse model of human Duchenne muscular dystrophy. Optical coherence tomography (OCT) images of excised muscle samples were compared with co-registered hematoxylin and eosin-stained and Evans blue dye fluorescence histology. We show, for the first time, structural 3D-OCT images of skeletal muscle dystropathology well correlated with co-located histology. OCT could identify morphological features of interest and necrotic lesions within the muscle tissue samples based on intrinsic optical contrast. These findings demonstrate the utility of 3D-OCT for the evaluation of small-animal skeletal muscle morphology and pathology, particularly for studies of mouse models of muscular dystrophy.
Collapse
Affiliation(s)
- Blake R Klyen
- The University of Western Australia, School of Electrical, Electronic and Computer Engineering, Optical+Biomedical Engineering Laboratory, M018, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
| | | | | | | | | |
Collapse
|
18
|
Czaplik M, Rossaint R, Koch E, Fahlenkamp A, Schröder W, Pelosi P, Kübler W, Bickenbach J. Methods for quantitative evaluation of alveolar structure during in vivo microscopy. Respir Physiol Neurobiol 2011; 176:123-9. [DOI: 10.1016/j.resp.2011.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 02/14/2011] [Indexed: 11/27/2022]
|
19
|
Schwenninger D, Runck H, Schumann S, Haberstroh J, Meissner S, Koch E, Guttmann J. Intravital microscopy of subpleural alveoli via transthoracic endoscopy. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:046002. [PMID: 21529071 DOI: 10.1117/1.3560297] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Transfer of too high mechanical energy from the ventilator to the lung's alveolar tissue is the main cause for ventilator-induced lung injury (VILI). To investigate the effects of cyclic energy transfer to the alveoli, we introduce a new method of transthoracic endoscopy that provides morphological as well as functional information about alveolar geometry and mechanics. We evaluate the new endoscopic method to continuously record images of focused subpleural alveoli. The method is evaluated by using finite element modeling techniques and by direct observation of subpleural alveoli both in isolated rat lungs as well as in intact animals (rats). The results confirm the overall low invasiveness of the endoscopic method insofar as the mechanical influences on the recorded alveoli are only marginal. It is, hence, a suited method for intravital microscopy in the rat model as well as in larger animals.
Collapse
Affiliation(s)
- David Schwenninger
- Division of Experimental Anaesthesiology, University Medical Center Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
20
|
Quirk BC, McLaughlin RA, Curatolo A, Kirk RW, Noble PB, Sampson DD. In situ imaging of lung alveoli with an optical coherence tomography needle probe. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:036009. [PMID: 21456872 DOI: 10.1117/1.3556719] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In situ imaging of alveoli and the smaller airways with optical coherence tomography (OCT) has significant potential in the assessment of lung disease. We present a minimally invasive imaging technique utilizing an OCT needle probe. The side-facing needle probe comprises miniaturized focusing optics consisting of no-core and GRIN fiber encased within a 23-gauge needle. 3D-OCT volumetric data sets were acquired by rotating and retracting the probe during imaging. The probe was used to image an intact, fresh (not fixed) sheep lung filled with normal saline, and the results validated against a histological gold standard. We present the first published images of alveoli acquired with an OCT needle probe and demonstrate the potential of this technique to visualize other anatomical features such as bifurcations of the bronchioles.
Collapse
Affiliation(s)
- Bryden C Quirk
- University of Western Australia, School of Electrical, Electronic & Computer Engineering, Crawley, WA 6009, Australia
| | | | | | | | | | | |
Collapse
|
21
|
Schwenninger D, Schumann S, Guttmann J. In vivo characterization of mechanical tissue properties of internal organs using endoscopic microscopy and inverse finite element analysis. J Biomech 2011; 44:487-93. [DOI: 10.1016/j.jbiomech.2010.09.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 09/03/2010] [Accepted: 09/15/2010] [Indexed: 11/28/2022]
|
22
|
In vivo microscopy in a porcine model of acute lung injury. Respir Physiol Neurobiol 2010; 172:192-200. [DOI: 10.1016/j.resp.2010.05.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 05/05/2010] [Accepted: 05/27/2010] [Indexed: 11/22/2022]
|
23
|
Yarmus L, Feller-Kopman D. Bronchoscopes of the twenty-first century. Clin Chest Med 2010; 31:19-27, Table of Contents. [PMID: 20172429 DOI: 10.1016/j.ccm.2009.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Over the past century, bronchoscopy has become an essential tool for pulmonologists and thoracic surgeons, who for many years have employed bronchoscopy with such therapeutic modalities as laser therapy, electrocautery, cryotherapy, and stent placement. Over the past decade, advanced imaging techniques, such as autofluoresence bronchoscopy, electromagnetic navigation, narrow-band imaging, confocal fluorescence microendoscopy, and endobronchial ultrasound, have greatly expanded the diagnostic utility of bronchoscopy. This article reviews the technological advances in the field of diagnostic bronchoscopy.
Collapse
Affiliation(s)
- Lonny Yarmus
- Interventional Pulmonology, Division of Pulmonary and Critical Care, The Johns Hopkins Hospital, 1830 East Monument Street, 5th Floor, Baltimore, MD 21205, USA
| | | |
Collapse
|
24
|
Yarmus L, Ernst A, Feller-Kopman D. Emerging technologies for the thorax: indications, management and complications. Respirology 2009; 15:208-19. [PMID: 20051044 DOI: 10.1111/j.1440-1843.2009.01680.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The field of interventional pulmonology has rapidly expanded to include the management and treatment of complex diseases of the chest. The management of central airway obstruction, pleural disease diagnosis, treatment and palliation, advanced bronchoscopic techniques to aid in the diagnosis of lung cancer and innovative therapies to treat asthma and COPD have all emerged over the past decade. As astute clinicians, we are all aware of the risks and benefits of using these therapies to treat our patients. In order to appropriately treat and manage these often complex medical situations, the physician should have an expert knowledge of all available modalities, the expertise to safely perform the procedure and the ability to minimize the risk of and manage the associated complications that may arise. In this chapter we review and update some of the bronchoscopic and pleural interventions offered by interventional pulmonologists as well as the associated complications and management.
Collapse
Affiliation(s)
- Lonny Yarmus
- Division of Interventional Pulmonology, The Johns Hopkins Hospital, Baltimore, Maryland 21205, USA
| | | | | |
Collapse
|