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Knudsen L, Brandenberger C, Ochs M. Stereology as the 3D tool to quantitate lung architecture. Histochem Cell Biol 2020; 155:163-181. [PMID: 33051774 PMCID: PMC7910236 DOI: 10.1007/s00418-020-01927-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2020] [Indexed: 01/12/2023]
Abstract
Stereology is the method of choice for the quantitative assessment of biological objects in microscopy. It takes into account the fact that, in traditional microscopy such as conventional light and transmission electron microscopy, although one has to rely on measurements on nearly two-dimensional sections from fixed and embedded tissue samples, the quantitative data obtained by these measurements should characterize the real three-dimensional properties of the biological objects and not just their “flatland” appearance on the sections. Thus, three-dimensionality is a built-in property of stereological sampling and measurement tools. Stereology is, therefore, perfectly suited to be combined with 3D imaging techniques which cover a wide range of complementary sample sizes and resolutions, e.g. micro-computed tomography, confocal microscopy and volume electron microscopy. Here, we review those stereological principles that are of particular relevance for 3D imaging and provide an overview of applications of 3D imaging-based stereology to the lung in health and disease. The symbiosis of stereology and 3D imaging thus provides the unique opportunity for unbiased and comprehensive quantitative characterization of the three-dimensional architecture of the lung from macro to nano scale.
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Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
| | - Christina Brandenberger
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
| | - Matthias Ochs
- Institute of Functional Anatomy, Charité-Universitätsmedizin Berlin, Philippstr. 11, 10115, Berlin, Germany. .,German Center for Lung Research (DZL), Berlin, Germany.
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DZHURAEV GEORGY, RODRÍGUEZ‐CASTILLO JOSÉALBERTO, RUIZ‐CAMP JORDI, SALWIG ISABELLE, SZIBOR MARTIN, VADÁSZ ISTVÁN, HEROLD SUSANNE, BRAUN THOMAS, AHLBRECHT KATRIN, ATZBERGER ANN, MÜHLFELD CHRISTIAN, SEEGER WERNER, MORTY RORYE. Estimation of absolute number of alveolar epithelial type 2 cells in mouse lungs: a comparison between stereology and flow cytometry. J Microsc 2019; 275:36-50. [DOI: 10.1111/jmi.12800] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 04/11/2019] [Accepted: 04/23/2019] [Indexed: 12/26/2022]
Affiliation(s)
- GEORGY DZHURAEV
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung ResearchBad Nauheim and German Center for Lung Research (DZL) Giessen Germany
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
| | - JOSÉ ALBERTO RODRÍGUEZ‐CASTILLO
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung ResearchBad Nauheim and German Center for Lung Research (DZL) Giessen Germany
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
| | - JORDI RUIZ‐CAMP
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung ResearchBad Nauheim and German Center for Lung Research (DZL) Giessen Germany
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
| | - ISABELLE SALWIG
- Department of Cardiac Development and RemodellingMax Planck Institute for Heart and Lung Research and German Center for Lung Research (DZL) Bad Nauheim Germany
| | - MARTIN SZIBOR
- Department of Cardiac Development and RemodellingMax Planck Institute for Heart and Lung Research and German Center for Lung Research (DZL) Bad Nauheim Germany
| | - ISTVÁN VADÁSZ
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
| | - SUSANNE HEROLD
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
| | - THOMAS BRAUN
- Department of Cardiac Development and RemodellingMax Planck Institute for Heart and Lung Research and German Center for Lung Research (DZL) Bad Nauheim Germany
| | - KATRIN AHLBRECHT
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung ResearchBad Nauheim and German Center for Lung Research (DZL) Giessen Germany
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
| | - ANN ATZBERGER
- Flow Cytometry UnitMax Planck Institute for Heart and Lung Research and German Center for Lung Research (DZL) Bad Nauheim Germany
| | - CHRISTIAN MÜHLFELD
- Hannover Medical SchoolInstitute of Functional and Applied Anatomy Hannover Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH) and German Center for Lung Research (DZL) Hannover Germany
| | - WERNER SEEGER
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung ResearchBad Nauheim and German Center for Lung Research (DZL) Giessen Germany
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
| | - RORY E. MORTY
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung ResearchBad Nauheim and German Center for Lung Research (DZL) Giessen Germany
- Department of Internal Medicine (Pulmonology)University of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL) Giessen Germany
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Schittny JC. How high resolution 3-dimensional imaging changes our understanding of postnatal lung development. Histochem Cell Biol 2018; 150:677-691. [PMID: 30390117 PMCID: PMC6267404 DOI: 10.1007/s00418-018-1749-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2018] [Indexed: 12/24/2022]
Abstract
During the last 10 + years biologically and clinically significant questions about postnatal lung development could be answered due to the application of modern cutting-edge microscopic and quantitative histological techniques. These are in particular synchrotron radiation based X-ray tomographic microscopy (SRXTM), but also 3Helium Magnetic Resonance Imaging, as well as the stereological estimation of the number of alveoli and the length of the free septal edge. First, the most important new finding may be the following: alveolarization of the lung does not cease after the maturation of the alveolar microvasculature but continues until young adulthood and, even more important, maybe reactivated lifelong if needed to rescue structural damages of the lungs. Second, the pulmonary acinus represents the functional unit of the lung. Because the borders of the acini could not be detected in classical histological sections, any investigation of the acini requires 3-dimensional (imaging) methods. Based on SRXTM it was shown that in rat lungs the number of acini stays constant, meaning that their volume increases by a factor of ~ 11 after birth. The latter is very important for acinar ventilation and particle deposition.
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Affiliation(s)
- Johannes C Schittny
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland.
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Barré SF, Haberthür D, Cremona TP, Stampanoni M, Schittny JC. The total number of acini remains constant throughout postnatal rat lung development. Am J Physiol Lung Cell Mol Physiol 2016; 311:L1082-L1089. [PMID: 27760763 DOI: 10.1152/ajplung.00325.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/10/2016] [Indexed: 12/14/2022] Open
Abstract
The pulmonary airways are subdivided into conducting and gas-exchanging airways. The small tree of gas-exchanging airways which is fed by the most distal conducting airway represents an acinus. Very little is known about the development of the number of acini. The goal of this study was to estimate their number throughout rat postnatal development. Right middle rat lung lobes were obtained at postnatal day 4-60, stained with heavy metals, paraffin embedded, and scanned by synchrotron radiation-based X-ray tomographic microscopy or imaged with micro computed tomography after critical point drying. The acini were counted by detection of the transitional bronchioles [bronchioalveolar duct junction (BADJ)] by using morphological criteria (thickness of the walls of airways and appearance of alveoli) during examination of the resulting three-dimensional (3D) image stacks. Between postnatal days 4-60, the number of acini per lung remained constant (5,840 ± 547 acini), but their volume increased significantly. We concluded that the acini are formed before the end of the saccular stage (before postnatal day 4) and that the developmental increase of the lung volume is achieved by an increase of the acinar volume and not by an increase of their number. Furthermore, our results propose that the bronchioalveolar stem cells, which are residing in the BADJ, are as constant in their location as the BADJ itself.
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Affiliation(s)
| | - David Haberthür
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland; and
| | | | - Marco Stampanoni
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland; and.,Institute for Biomedical Engineering, Swiss Federal Institute of Technology and University of Zürich, Zürich, Switzerland
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Kizhakke Puliyakote AS, Vasilescu DM, Newell JD, Wang G, Weibel ER, Hoffman EA. Morphometric differences between central vs. surface acini in A/J mice using high-resolution micro-computed tomography. J Appl Physiol (1985) 2016; 121:115-22. [PMID: 27174924 DOI: 10.1152/japplphysiol.00317.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/06/2016] [Indexed: 11/22/2022] Open
Abstract
Through interior tomography, high-resolution microcomputed tomography (μCT) systems provide the ability to nondestructively assess the pulmonary acinus at micron and submicron resolutions. With the application of systematic uniform random sampling (SURS) principles applied to in situ fixed, intact, ex vivo lungs, we have sought to characterize morphometric differences in central vs. surface acini to better understand how well surface acini reflect global acinar geometry. Lungs from six mice (A/J strain, 15-20 wk of age) were perfusion fixed in situ and imaged using a multiresolution μCT system (Micro XCT 400, Zeiss). With the use of lower-resolution whole lung images, SURS methods were used for identification of central and surface foci for high-resolution imaging. Acinar morphometric metrics included diameters, lengths, and branching angles for each alveolar duct and total path lengths from entrance of the acinus to the terminal alveolar sacs. In addition, acinar volume, alveolar surface area, and surface area/volume ratios were assessed. A generation-based analysis demonstrated that central acini have significantly smaller branch diameters at each generation with no significant increase in branch lengths. In addition to larger-diameter alveolar ducts, surface acini had significantly increased numbers of branches and terminal alveolar sacs. The total path lengths from the acinar entrance to the terminal nodes were found to be higher in the case of surface acini. Volumes and surface areas of surface acini are greater than central acini, but there were no differences in surface/volume ratios. In conclusion, there are significant structural differences between surface and central acini in the A/J mouse.
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Affiliation(s)
- Abhilash S Kizhakke Puliyakote
- Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa
| | | | - John D Newell
- Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa
| | - Ge Wang
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; Department of Biomedical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | | | - Eric A Hoffman
- Department of Radiology, University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa; Department of Medicine, University of Iowa, Iowa City, Iowa;
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Abstract
Structural and functional complexities of the mammalian lung evolved to meet a unique set of challenges, namely, the provision of efficient delivery of inspired air to all lung units within a confined thoracic space, to build a large gas exchange surface associated with minimal barrier thickness and a microvascular network to accommodate the entire right ventricular cardiac output while withstanding cyclic mechanical stresses that increase several folds from rest to exercise. Intricate regulatory mechanisms at every level ensure that the dynamic capacities of ventilation, perfusion, diffusion, and chemical binding to hemoglobin are commensurate with usual metabolic demands and periodic extreme needs for activity and survival. This article reviews the structural design of mammalian and human lung, its functional challenges, limitations, and potential for adaptation. We discuss (i) the evolutionary origin of alveolar lungs and its advantages and compromises, (ii) structural determinants of alveolar gas exchange, including architecture of conducting bronchovascular trees that converge in gas exchange units, (iii) the challenges of matching ventilation, perfusion, and diffusion and tissue-erythrocyte and thoracopulmonary interactions. The notion of erythrocytes as an integral component of the gas exchanger is emphasized. We further discuss the signals, sources, and limits of structural plasticity of the lung in alveolar hypoxia and following a loss of lung units, and the promise and caveats of interventions aimed at augmenting endogenous adaptive responses. Our objective is to understand how individual components are matched at multiple levels to optimize organ function in the face of physiological demands or pathological constraints.
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Affiliation(s)
- Connie C.W. Hsia
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Dallas M. Hyde
- California National Primate Research Center, University of California at Davis, Davis, California, USA
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Barré SF, Haberthür D, Stampanoni M, Schittny JC. Efficient estimation of the total number of acini in adult rat lung. Physiol Rep 2014; 2:2/7/e12063. [PMID: 24997068 PMCID: PMC4187566 DOI: 10.14814/phy2.12063] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Pulmonary airways are subdivided into conducting and gas‐exchanging airways. An acinus is defined as the small tree of gas‐exchanging airways, which is fed by the most distal purely conducting airway. Until now a dissector of five consecutive sections or airway casts were used to count acini. We developed a faster method to estimate the number of acini in young adult rats. Right middle lung lobes were critical point dried or paraffin embedded after heavy metal staining and imaged by X‐ray micro‐CT or synchrotron radiation‐based X‐rays tomographic microscopy. The entrances of the acini were counted in three‐dimensional (3D) stacks of images by scrolling through them and using morphological criteria (airway wall thickness and appearance of alveoli). Segmentation stopper were placed at the acinar entrances for 3D visualizations of the conducting airways. We observed that acinar airways start at various generations and that one transitional bronchiole may serve more than one acinus. A mean of 5612 (±547) acini per lung and a mean airspace volume of 0.907 (±0.108) μL per acinus were estimated. In 60‐day‐old rats neither the number of acini nor the mean acinar volume did correlate with the body weight or the lung volume. An efficient method to estimate the number of acini in young adult rats has been developed. All entrances of the acini were counted, labeled, and visualized in three‐dimensional stacks of X‐ray tomographic images. We observed that acinar airways start at various generations and that one transitional bronchiole may serve more than one acinus. A mean of 5612 (±547) acini per lung and a mean acinar airspace volume of 0.907 (±0.108) µL were estimated.
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Affiliation(s)
| | - David Haberthür
- Institute of Anatomy, University of Bern, Bern, Switzerland Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Zürich, Switzerland
| | - Marco Stampanoni
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Zürich, Switzerland
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Ochs M. Estimating structural alterations in animal models of lung emphysema. Is there a gold standard? Ann Anat 2013; 196:26-33. [PMID: 24268708 DOI: 10.1016/j.aanat.2013.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 10/07/2013] [Accepted: 10/12/2013] [Indexed: 01/08/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is one of the most common lung diseases. The major component of COPD, which affects the gas-exchanging parenchyma of the lung, emphysema, is characterized by destruction of alveolar septae leading to loss of functional surface, loss of alveoli and enlargement of remaining distal airspaces. These microstructural alterations can be modeled in animals and can be measured using stereological methods applied to imaging datasets. Many animal models of emphysema exist, but most of them are insufficiently characterized with respect to the underlying nature (e.g. destructive or developmental) and the degree of the structural alterations. The most popular parameter for assessment of emphysematous alterations, mean linear intercept length, has severe limitations. It can, therefore, not be recommended. Better design-based stereological alternatives exist but are less often applied, such as total volumes of parenchymal compartments (alveolar airspace, alveolar duct airspace, alveolar septum), total alveolar surface area, total alveolar number and mean alveolar size and its size variation. A prerequisite is the use of appropriate fixation, sampling, and specimen processing protocols. This article reviews the challenges of stereologic assessment of emphysematous alterations in the lung and illustrates possible strategies.
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Affiliation(s)
- Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany; REBIRTH Cluster of Excellence, Hannover, Germany.
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Haberthür D, Barré SF, Tschanz SA, Yao E, Stampanoni M, Schittny JC. Visualization and stereological characterization of individual rat lung acini by high-resolution X-ray tomographic microscopy. J Appl Physiol (1985) 2013; 115:1379-87. [DOI: 10.1152/japplphysiol.00642.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The small trees of gas-exchanging pulmonary airways, which are fed by the most distal purely conducting airways, are called acini and represent the functional gas-exchanging units. The three-dimensional architecture of the acini has a strong influence on ventilation and particle deposition. Due to the difficulty in identifying individual acini on microscopic lung sections, the knowledge about the number of acini and their biological parameters, like volume, surface area, and number of alveoli per acinus, are limited. We developed a method to extract individual acini from lungs imaged by high-resolution synchrotron radiation-based X-ray tomographic microscopy and estimated their volume, surface area, and number of alveoli. Rat acini were isolated by semiautomatically closing the airways at the transition from conducting to gas-exchanging airways. We estimated a mean internal acinar volume of 1.148 mm3, a mean acinar surface area of 73.9 mm2, and a mean of 8,470 alveoli/acinus. Assuming that the acini are similarly sized throughout different regions of the lung, we calculated that a rat lung contains 5,470 ± 833 acini. We conclude that our novel approach is well suited for the fast and reliable characterization of a large number of individual acini in healthy, diseased, or transgenic lungs of different species, including humans.
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Affiliation(s)
- David Haberthür
- Institute of Anatomy, University of Bern, Bern, Switzerland
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland; and
| | | | | | - Eveline Yao
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Marco Stampanoni
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland; and
- Institute for Biomedical Engineering, Swiss Federal Institute of Technology and University of Zürich, Zürich, Switzerland
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Vasilescu DM, Klinge C, Knudsen L, Yin L, Wang G, Weibel ER, Ochs M, Hoffman EA. Stereological assessment of mouse lung parenchyma via nondestructive, multiscale micro-CT imaging validated by light microscopic histology. J Appl Physiol (1985) 2012; 114:716-24. [PMID: 23264542 DOI: 10.1152/japplphysiol.00855.2012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Quantitative assessment of the lung microstructure using standard stereological methods such as volume fractions of tissue, alveolar surface area, or number of alveoli, are essential for understanding the state of normal and diseased lung. These measures are traditionally obtained from histological sections of the lung tissue, a process that ultimately destroys the three-dimensional (3-D) anatomy of the tissue. In comparison, a novel X-ray-based imaging method that allows nondestructive sectioning and imaging of fixed lungs at multiple resolutions can overcome this limitation. Scanning of the whole lung at high resolution and subsequent regional sampling at ultrahigh resolution without physically dissecting the organ allows the application of design-based stereology for assessment of the whole lung structure. Here we validate multiple stereological estimates performed on micro-computed tomography (μCT) images by comparing them with those obtained via conventional histology on the same mouse lungs. We explore and discuss the potentials and limitations of the two approaches. Histological examination offers higher resolution and the qualitative differentiation of tissues by staining, but ultimately loses 3-D tissue relationships, whereas μCT allows for the integration of morphometric data with the spatial complexity of lung structure. However, μCT has limited resolution satisfactory for the sterological estimates presented in this study but not for differentiation of tissues. We conclude that introducing stereological methods in μCT studies adds value by providing quantitative information on internal structures while not curtailing more complex approaches to the study of lung architecture in the context of physiological or pathological studies.
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