1
|
Seifelnasr A, Si XA, Xi J. Visualization and Estimation of Nasal Spray Delivery to Olfactory Mucosa in an Image-Based Transparent Nasal Model. Pharmaceutics 2023; 15:1657. [PMID: 37376105 DOI: 10.3390/pharmaceutics15061657] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/25/2023] [Accepted: 06/04/2023] [Indexed: 06/29/2023] Open
Abstract
Background: Nose-to-brain (N2B) drug delivery offers unique advantages over intravenous methods; however, the delivery efficiency to the olfactory region using conventional nasal devices and protocols is low. This study proposes a new strategy to effectively deliver high doses to the olfactory region while minimizing dose variability and drug losses in other regions of the nasal cavity. Materials and Methods: The effects of delivery variables on the dosimetry of nasal sprays were systematically evaluated in a 3D-printed anatomical model that was generated from a magnetic resonance image of the nasal airway. The nasal model comprised four parts for regional dose quantification. A transparent nasal cast and fluorescent imaging were used for visualization, enabling detailed examination of the transient liquid film translocation, real-time feedback on input effect, and prompt adjustment to delivery variables, which included the head position, nozzle angle, applied dose, inhalation flow, and solution viscosity. Results: The results showed that the conventional vertex-to-floor head position was not optimal for olfactory delivery. Instead, a head position tilting 45-60° backward from the supine position gave a higher olfactory deposition and lower variability. A two-dose application (250 mg) was necessary to mobilize the liquid film that often accumulated in the front nose following the first dose administration. The presence of an inhalation flow reduced the olfactory deposition and redistributed the sprays to the middle meatus. The recommended olfactory delivery variables include a head position ranging 45-60°, a nozzle angle ranging 5-10°, two doses, and no inhalation flow. With these variables, an olfactory deposition fraction of 22.7 ± 3.7% was achieved in this study, with insignificant discrepancies in olfactory delivery between the right and left nasal passages. Conclusions: It is feasible to deliver clinically significant doses of nasal sprays to the olfactory region by leveraging an optimized combination of delivery variables.
Collapse
Affiliation(s)
- Amr Seifelnasr
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA 01854, USA
| | - Xiuhua April Si
- Department of Mechanical Engineering, California Baptist University, Riverside, CA 92504, USA
| | - Jinxiang Xi
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA 01854, USA
| |
Collapse
|
2
|
Fleming JS, Conway J, Bennett MJ, Tossici-Bolt L, Guy M, Blé FX, McCrae C, Carlsson M, Bondesson E. Quantitative Assessment of Regional Mucociliary Clearance in Smokers with Mild-to-Moderate Chronic Obstructive Pulmonary Disease and Chronic Bronchitis from Planar Radionuclide Imaging. J Aerosol Med Pulm Drug Deliv 2020; 33:342-356. [PMID: 32640859 DOI: 10.1089/jamp.2019.1551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: Mucociliary clearance (MCC) rate from the lung has been shown to be reduced in chronic obstructive pulmonary disease (COPD). This study investigates the value of regional clearance measurements in assessing MCC in mild-to-moderate disease. Methods: Measurement of lung MCC using planar gamma camera imaging was performed in three groups: (i) healthy nonsmoking controls (NSCs) (n = 9), (ii) smoking controls (SCs) who were current smokers with normal lung function (n = 10), and (iii) current smokers with mild-to-moderate COPD and bronchitis (n = 15). The mean (±standard deviation) forced expiratory volumes at 1 second (FEV1) for the three groups were 109 (± 18), 94 (± 5), and 78 (± 12), respectively. After inhalation of a technetium-99m labeled aerosol, planar imaging was performed over 4 hours and then at 24 hours. Both lung clearance and tracheobronchial clearance (TBC) (normalized to 24 hours clearance) were calculated for inner and outer lung zones. Inner zone clearance was corrected for input from the outer zone. A novel parameter, the bronchial airways clearance index (BACI), which combined clearance data from both zones, was also evaluated. Regional results were compared with whole lung clearance in the same subjects. Results: Corrected inner zone clearance at 3 hours was not reduced compared with NSC in either SCs or COPD. Outer zone clearance was higher in COPD than in the other groups. Corrected inner zone TBC showed significant reductions in SC and COPD compared with NSC. BACI was significantly reduced in COPD compared with NSC and also correlated with FEV1. The mean BACI for SC was also reduced compared with NSC, but the distribution of results was bimodal, with a significant proportion of subjects having values in the NSC range. Conclusions: Regional MCC demonstrated differences between NSCs, SCs, and subjects with mild-to-moderate COPD, which were not apparent with whole lung measurements.
Collapse
Affiliation(s)
- John S Fleming
- Southampton NIHR Respiratory and Critical Care Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Joy Conway
- Southampton NIHR Respiratory and Critical Care Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Centre for Health and Life Sciences, Brunel University, London, United Kingdom
| | - Michael J Bennett
- Southampton NIHR Respiratory and Critical Care Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Livia Tossici-Bolt
- Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Matthew Guy
- Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - François-Xavier Blé
- Translational Science and Experimental Medicine, Research and Early Development, Respiratory, Inflammation and Autoimmune (RIA), R&D BioPharmaceuticals, AstraZeneca R&D, Gothenburg, Sweden
| | - Christopher McCrae
- Translational Science and Experimental Medicine, Research and Early Development, Respiratory, Inflammation and Autoimmune (RIA), R&D BioPharmaceuticals, AstraZeneca R&D, Gothenburg, Sweden
| | - Mats Carlsson
- Patient Safety, Chief Medical Office, R&D, AstraZeneca, Gothenburg, Sweden
| | | |
Collapse
|
3
|
Alcoforado L, Dornelas de Andrade A, Herraiz JL, Brandão SCS, Barcelar JDM, Fink JB, Venegas JG. Anatomically Based Analysis of Radioaerosol Distribution in Pulmonary Scintigraphy: A Feasibility Study in Asthmatics. J Aerosol Med Pulm Drug Deliv 2018; 31:298-310. [PMID: 29672215 PMCID: PMC6161331 DOI: 10.1089/jamp.2017.1403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
INTRODUCTION Manual analysis of two-dimensional (2D) scintigraphy to evaluate aerosol deposition is usually subjective and has reduced sensitivity to quantify regional differences between central and distal airways. AIMS (1) To present a method to analyze 2D scans based on three-dimensional (3D)-linked anatomically consistent regions of interest (ROIs); (2) to evaluate peripheral-to-central counts ratio (P/C2D) and penetration indices (PIs) for a set of 16 subjects with moderate-to-severe asthma; and (3) to compare the reproducibility of this method against one with manually traced ROIs. METHODS Two-dimensional scans were analyzed using custom software that scaled onto 2D-projections' 3D anatomical features, obtained from population-averaged computed tomography (CT) chest scans. ROIs for a rectangular box (bROI) and an anatomically shaped ROI (aROI) were defined by computer and by manually tracing the standard rectangular box (manual ROI [mROI]). These ROIs were defined five nonconsecutive times for each scan and average value and variability of the P/C2D were estimated. Based on CT estimates of lung and airways, volumes lying under the bROI and aROI, a 2D penetration index (PI2D) and a 3D penetration index (PI3D), were defined as volume-normalized ratios of aerosol deposition in central and peripheral ROIs and in central and distal airways, respectively. RESULTS P/C2D values and their variability, were influenced by the shape and method to define the ROIs: The P/C2D was systematically greater and more variable for mROI versus bROI (p < 0.005). The P/C2D for aROI was higher and its variability lower than those for the bROI (p < 0.001). The PI2D was in average the same for aROI and bROI, and is substantially (∼30 × ) greater than PI3D (p < 0.001). Both PI2D and PI3D, obtained with our analysis, compared well with literature values obtained with two scans (deposition and volume). CONCLUSION Our results demonstrate that 2D scintigraphy can be analyzed using anatomically based ROIs from 3D CT data, allowing objective and enhanced reproducibility values describing the distribution pattern of radioaerosol deposition in the tracheobronchial tree.
Collapse
Affiliation(s)
- Luciana Alcoforado
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Brazil
| | | | - Joaquin L. Herraiz
- Grupo de Fisica Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Madrid, Spain
| | | | | | | | - Jose G. Venegas
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- Address correspondence to:Jose G. Venegas, PhDDepartment of AnesthesiaEdwards 410Massachusetts General Hospital55 Fruit St.Boston, MA 02114
| |
Collapse
|
4
|
Alcoforado L, Dornelas de Andrade A, Herraiz JL, Brandão SCS, Barcelar JDM, Fink JB, Venegas JG. Anatomically Based Analysis of Radioaerosol Distribution in Pulmonary Scintigraphy: A Feasibility Study in Asthmatics. J Aerosol Med Pulm Drug Deliv 2018. [DOI: https://doi.org/10.1089/jamp.2017.1403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Luciana Alcoforado
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Brazil
| | | | - Joaquin L. Herraiz
- Grupo de Fisica Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Madrid, Spain
| | | | | | | | - Jose G. Venegas
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
5
|
Kolanjiyil AV, Kleinstreuer C, Sadikot RT. Computationally efficient analysis of particle transport and deposition in a human whole-lung-airway model. Part II: Dry powder inhaler application. Comput Biol Med 2016; 84:247-253. [PMID: 27836120 DOI: 10.1016/j.compbiomed.2016.10.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 10/04/2016] [Accepted: 10/31/2016] [Indexed: 10/20/2022]
Abstract
Pulmonary drug delivery is becoming a favored route for administering drugs to treat both lung and systemic diseases. Examples of lung diseases include asthma, cystic fibrosis and chronic obstructive pulmonary disease (COPD) as well as respiratory distress syndrome (ARDS) and pulmonary fibrosis. Special respiratory drugs are administered to the lungs, using an appropriate inhaler device. Next to the pressurized metered-dose inhaler (pMDI), the dry powder inhaler (DPI) is a frequently used device because of the good drug stability and a minimal need for patient coordination. Specific DPI-designs and operations greatly affect drug-aerosol formation and hence local lung deposition. Simulating the fluid-particle dynamics after use of a DPI allows for the assessment of drug-aerosol deposition and can also assist in improving the device configuration and operation. In Part I of this study a first-generation whole lung-airway model (WLAM) was introduced and discussed to analyze particle transport and deposition in a human respiratory tract model. In the present Part II the drug-aerosols are assumed to be injected into the lung airways from a DPI mouth-piece, forming the mouth-inlet. The total as well as regional particle depositions in the WLAM, as inhaled from a DPI, were successfully compared with experimental data sets reported in the open literature. The validated modeling methodology was then employed to study the delivery of curcumin aerosols into lung airways using a commercial DPI. Curcumin has been implicated to possess high therapeutic potential as an antioxidant, anti-inflammatory and anti-cancer agent. However, efficacy of curcumin treatment is limited because of the low bioavailability of curcumin when ingested. Hence, alternative drug administration techniques, e.g., using inhalable curcumin-aerosols, are under investigation. Based on the present results, it can be concluded that use of a DPI leads to low lung deposition efficiencies because large amounts of drugs are deposited in the oral cavity. Hence, the output of a modified DPI has been evaluated to achieve improved drug delivery, especially needed when targeting the smaller lung airways. This study is the first to utilize CF-PD methodology to simulate drug-aerosol transport and deposition under actual breathing conditions in a whole lung model, using a commercial dry-powder inhaler for realistic inlet conditions.
Collapse
Affiliation(s)
- Arun V Kolanjiyil
- Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, United States
| | - Clement Kleinstreuer
- Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, United States; Joint UNC-NCSU Department of Biomedical Engineering, North Carolina State University, Raleigh, NC 27695-7910, United States.
| | - Ruxana T Sadikot
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, School of Medicine, United States; Department of Veterans Affairs, Atlanta VAMC, United States
| |
Collapse
|
6
|
Xi J, Yuan JE, Zhang Y, Nevorski D, Wang Z, Zhou Y. Visualization and Quantification of Nasal and Olfactory Deposition in a Sectional Adult Nasal Airway Cast. Pharm Res 2016; 33:1527-41. [PMID: 26943943 DOI: 10.1007/s11095-016-1896-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 03/01/2016] [Indexed: 12/11/2022]
Abstract
PURPOSE To compare drug deposition in the nose and olfactory region with different nasal devices and administration techniques. A Sar-Gel based colorimetry method will be developed to quantify local deposition rates. METHODS A sectional nasal airway cast was developed based on an MRI-based nasal airway model to visualize deposition patterns and measure regional dosages. Four nasal spray pumps and four nebulizers were tested with both standard and point-release administration techniques. Delivered dosages were measured using a high-precision scale. The colorimetry correlation for deposited mass was developed via image processing in Matlab and its performance was evaluated through comparison to experimental measurements. RESULTS Results show that the majority of nasal spray droplets deposited in the anterior nose while only a small fraction (less than 4.6%) reached the olfactory region. For all nebulizers considered, more droplets went beyond the nasal valve, leading to distinct deposition patterns as a function of both the nebulizer type (droplet size and initial speed) and inhalation flow rate. With the point-release administration, up to 9.0% (±1.9%) of administered drugs were delivered to the olfactory region and 15.7 (±2.4%) to the upper nose using Pari Sinus. CONCLUSIONS Standard nasal devices are inadequate to deliver clinically significant olfactory dosages without excess drug losses in other nasal epitheliums. The Sar-Gel based colorimetry method appears to provide a simple and practical approach to visualize and quantify regional deposition.
Collapse
Affiliation(s)
- Jinxiang Xi
- School of Engineering and Technology, Central Michigan University, 1200 South Franklin Street, Mount Pleasant, MI, 48858, USA.
| | - Jiayao Eddie Yuan
- Department of Mechanical Engineering, Columbia University, New York, New York, USA
| | - Yu Zhang
- School of Engineering and Technology, Central Michigan University, 1200 South Franklin Street, Mount Pleasant, MI, 48858, USA
| | - Dannielle Nevorski
- School of Engineering and Technology, Central Michigan University, 1200 South Franklin Street, Mount Pleasant, MI, 48858, USA
| | - Zhaoxuan Wang
- School of Engineering and Technology, Central Michigan University, 1200 South Franklin Street, Mount Pleasant, MI, 48858, USA
| | - Yue Zhou
- Aerosol and Respiratory Dosimetry Program, Lovelace Respiratory Research Institute, Albuquerque, New York, USA
| |
Collapse
|
7
|
Darquenne C, Fleming JS, Katz I, Martin AR, Schroeter J, Usmani OS, Venegas J, Schmid O. Bridging the Gap Between Science and Clinical Efficacy: Physiology, Imaging, and Modeling of Aerosols in the Lung. J Aerosol Med Pulm Drug Deliv 2016; 29:107-26. [PMID: 26829187 DOI: 10.1089/jamp.2015.1270] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Development of a new drug for the treatment of lung disease is a complex and time consuming process involving numerous disciplines of basic and applied sciences. During the 2015 Congress of the International Society for Aerosols in Medicine, a group of experts including aerosol scientists, physiologists, modelers, imagers, and clinicians participated in a workshop aiming at bridging the gap between basic research and clinical efficacy of inhaled drugs. This publication summarizes the current consensus on the topic. It begins with a short description of basic concepts of aerosol transport and a discussion on targeting strategies of inhaled aerosols to the lungs. It is followed by a description of both computational and biological lung models, and the use of imaging techniques to determine aerosol deposition distribution (ADD) in the lung. Finally, the importance of ADD to clinical efficacy is discussed. Several gaps were identified between basic science and clinical efficacy. One gap between scientific research aimed at predicting, controlling, and measuring ADD and the clinical use of inhaled aerosols is the considerable challenge of obtaining, in a single study, accurate information describing the optimal lung regions to be targeted, the effectiveness of targeting determined from ADD, and some measure of the drug's effectiveness. Other identified gaps were the language and methodology barriers that exist among disciplines, along with the significant regulatory hurdles that need to be overcome for novel drugs and/or therapies to reach the marketplace and benefit the patient. Despite these gaps, much progress has been made in recent years to improve clinical efficacy of inhaled drugs. Also, the recent efforts by many funding agencies and industry to support multidisciplinary networks including basic science researchers, R&D scientists, and clinicians will go a long way to further reduce the gap between science and clinical efficacy.
Collapse
Affiliation(s)
- Chantal Darquenne
- 1 Department of Medicine, University of California , San Diego, La Jolla, California
| | - John S Fleming
- 2 National Institute of Health Research Biomedical Research Unit in Respiratory Disease , Southampton, United Kingdom .,3 Department of Medical Physics and Bioengineering, University Hospital Southampton NHS Foundation Trust , Southampton, United Kingdom
| | - Ira Katz
- 4 Medical R&D, Air Liquide Santé International, Centre de Recherche Paris-Saclay , Jouy-en-Josas, France .,5 Department of Mechanical Engineering, Lafayette College , Easton, Pennsylvania
| | - Andrew R Martin
- 6 Department of Mechanical Engineering, University of Alberta , Edmonton, Alberta, Canada
| | | | - Omar S Usmani
- 8 Airway Disease Section, National Heart and Lung Institute , Imperial College London and Royal Brompton Hospital, London, United Kingdom
| | - Jose Venegas
- 9 Department of Anesthesia (Bioengineering), MGH/Harvard, Boston, Massachusetts
| | - Otmar Schmid
- 10 Comprehensive Pneumology Center (CPC), Member of the German Center for Lung Research , Munich, Germany .,11 Institute of Lung Biology and Disease, Helmholtz Zentrum München-German Research Center for Environmental Health , Neuherberg, Germany
| |
Collapse
|
8
|
Forbes B, Bäckman P, Christopher D, Dolovich M, Li BV, Morgan B. In Vitro Testing for Orally Inhaled Products: Developments in Science-Based Regulatory Approaches. AAPS JOURNAL 2015; 17:837-52. [PMID: 25940082 DOI: 10.1208/s12248-015-9763-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/30/2015] [Indexed: 11/30/2022]
Abstract
This article is part of a series of reports from the "Orlando Inhalation Conference-Approaches in International Regulation" which was held in March 2014, and coorganized by the University of Florida and the International Pharmaceutical Aerosol Consortium on Regulation and Science (IPAC-RS). The goal of the conference was to foster the exchange of ideas and knowledge across the global scientific and regulatory community in order to identify and help move towards strategies for internationally harmonized, science-based regulatory approaches for the development and marketing approval of inhalation medicines, including innovator and second entry products. This article provides an integrated perspective of case studies and discussion related to in vitro testing of orally inhaled products, including in vitro-in vivo correlations and requirements for in vitro data and statistical analysis that support quality or bioequivalence for regulatory applications.
Collapse
Affiliation(s)
- Ben Forbes
- Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, London, SE1 9NH, UK,
| | | | | | | | | | | |
Collapse
|
9
|
Fleming J, Conway J, Majoral C, Katz I, Caillibotte G, Pichelin M, Montesantos S, Bennett M. Controlled, Parametric, Individualized, 2-D and 3-D Imaging Measurements of Aerosol Deposition in the Respiratory Tract of Asthmatic Human Subjects for Model Validation. J Aerosol Med Pulm Drug Deliv 2015; 28:432-51. [PMID: 25859710 DOI: 10.1089/jamp.2014.1191] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Computer modeling is used to predict inhaled aerosol deposition in the lung based on definition of the aerosol characteristics and the breathing pattern and airway anatomy of the subject. Validation of the models is limited by the lack of detailed experimental data. Three-dimensional imaging provides an opportunity to address this unmet need. METHODS Radioactive aerosol was administered to six male asthmatic subjects on two occasions under carefully monitored input conditions. Input parameters varied in particle size, depth of breathing, and carrier gas. The aerosol distribution was measured by combined single photon emission computed tomography and x-ray computer tomography (SPECT/CT) and airway anatomy by high resolution CT. The deposition distribution was measured by both a 2D and 3D analysis and described in terms of the percentage of inhaled aerosol deposited in sections of the respiratory tract and in both spatial and anatomical subdivisions within each lung. The percentage deposition in the conducting airways was also assessed by 24 h clearance. RESULTS A set of imaging data of aerosol deposition has thus been produced in which the input parameters of inhalation are well described. The results in asthmatics were compared to previous measurements in healthy controls using an identical inhalation protocol. The percentages of deposition in extra-thoracic and thoracic compartments of the airways were not significantly affected by disease, but the regional pulmonary deposition pattern was, with asthma leading to increased deposition in the conducting airways. CONCLUSIONS The dataset acquired in this study will be useful in validating computer models of aerosol deposition in asthmatic subjects. Asthma did not affect the fraction of inhaled aerosol depositing in the lungs, but gave rise to a more central deposition pattern. The use of 3D SPECT imaging in combination with 24 h clearance measurements enables differentiation of deposition between bronchial and bronchiolar airways.
Collapse
Affiliation(s)
- John Fleming
- 1 National Institute of Health Research Biomedical Research Unit in Respiratory Disease , Southampton, United Kingdom .,2 Department of Medical Physics and Bioengineering, University Hospital Southampton NHS Foundation Trust , Southampton, United Kingdom .,4 Medical R&D, Air Liquide Santé International, Paris-Saclay Research Center , Les Loges-en-Josas, France
| | - Joy Conway
- 1 National Institute of Health Research Biomedical Research Unit in Respiratory Disease , Southampton, United Kingdom .,3 Faculty of Health Sciences, University of Southampton , Southampton, United Kingdom
| | - Caroline Majoral
- 4 Medical R&D, Air Liquide Santé International, Paris-Saclay Research Center , Les Loges-en-Josas, France
| | - Ira Katz
- 4 Medical R&D, Air Liquide Santé International, Paris-Saclay Research Center , Les Loges-en-Josas, France .,5 Department of Mechanical Engineering, Lafayette College , Easton, Pennsylvania
| | - Georges Caillibotte
- 4 Medical R&D, Air Liquide Santé International, Paris-Saclay Research Center , Les Loges-en-Josas, France
| | - Marine Pichelin
- 4 Medical R&D, Air Liquide Santé International, Paris-Saclay Research Center , Les Loges-en-Josas, France
| | - Spyridon Montesantos
- 4 Medical R&D, Air Liquide Santé International, Paris-Saclay Research Center , Les Loges-en-Josas, France
| | - Michael Bennett
- 1 National Institute of Health Research Biomedical Research Unit in Respiratory Disease , Southampton, United Kingdom
| |
Collapse
|
10
|
Löndahl J, Möller W, Pagels JH, Kreyling WG, Swietlicki E, Schmid O. Measurement techniques for respiratory tract deposition of airborne nanoparticles: a critical review. J Aerosol Med Pulm Drug Deliv 2014; 27:229-54. [PMID: 24151837 PMCID: PMC4120654 DOI: 10.1089/jamp.2013.1044] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 09/15/2013] [Indexed: 12/14/2022] Open
Abstract
Determination of the respiratory tract deposition of airborne particles is critical for risk assessment of air pollution, inhaled drug delivery, and understanding of respiratory disease. With the advent of nanotechnology, there has been an increasing interest in the measurement of pulmonary deposition of nanoparticles because of their unique properties in inhalation toxicology and medicine. Over the last century, around 50 studies have presented experimental data on lung deposition of nanoparticles (typical diameter≤100 nm, but here≤300 nm). These data show a considerable variability, partly due to differences in the applied methodologies. In this study, we review the experimental techniques for measuring respiratory tract deposition of nano-sized particles, analyze critical experimental design aspects causing measurement uncertainties, and suggest methodologies for future studies. It is shown that, although particle detection techniques have developed with time, the overall methodology in respiratory tract deposition experiments has not seen similar progress. Available experience from previous research has often not been incorporated, and some methodological design aspects that were overlooked in 30-70% of all studies may have biased the experimental data. This has contributed to a significant uncertainty on the absolute value of the lung deposition fraction of nanoparticles. We estimate the impact of the design aspects on obtained data, discuss solutions to minimize errors, and highlight gaps in the available experimental set of data.
Collapse
Affiliation(s)
- Jakob Löndahl
- Ergonomics and Aerosol Technology (EAT), Lund University, SE-221 00 Lund, Sweden
| | - Winfried Möller
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Joakim H. Pagels
- Ergonomics and Aerosol Technology (EAT), Lund University, SE-221 00 Lund, Sweden
| | - Wolfgang G. Kreyling
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | | | - Otmar Schmid
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| |
Collapse
|
11
|
Conway J, Fleming J, Bennett M, Havelock T. The co-imaging of gamma camera measurements of aerosol deposition and respiratory anatomy. J Aerosol Med Pulm Drug Deliv 2013; 26:123-30. [PMID: 23517170 DOI: 10.1089/jamp.2011.0960] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The use of gamma camera imaging following the inhalation of a radiolabel has been widely used by researchers to investigate the fate of inhaled aerosols. The application of two-dimensional (2D) planar gamma scintigraphy and single-photon emission computed tomography (SPECT) to the study of inhaled aerosols is discussed in this review. Information on co-localized anatomy can be derived from other imaging techniques such as krypton ventilation scans and low- and high-resolution X-ray computed tomography (CT). Radionuclide imaging, combined with information on anatomy, is a potentially useful approach when the understanding of regional deposition within the lung is central to research objectives for following disease progression and for the evaluation of therapeutic intervention.
Collapse
Affiliation(s)
- Joy Conway
- Faculty of Health Sciences, University of Southampton, Southampton, UK SO16 6YD.
| | | | | | | |
Collapse
|
12
|
Venegas J, Winkler T, Harris RS. Lung Physiology and Aerosol Deposition Imaged with Positron Emission Tomography. J Aerosol Med Pulm Drug Deliv 2013; 26:1-8. [DOI: 10.1089/jamp.2011.0944] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jose Venegas
- Department of Anesthesia (Bioengineering), MGH/Harvard, Boston, Massachusetts
| | - Tilo Winkler
- Department of Anesthesia (Bioengineering), MGH/Harvard, Boston, Massachusetts
| | - R. Scott Harris
- Department of Pulmonary, Critical Care, and Sleep Medicine, MGH/Harvard, Boston, Massachusetts
| |
Collapse
|
13
|
Newman S, Bennett WD, Biddiscombe M, Devadason SG, Dolovich MB, Fleming J, Haeussermann S, Kietzig C, Kuehl PJ, Laube BL, Sommerer K, Taylor G, Usmani OS, Zeman KL. Standardization of Techniques for Using Planar (2D) Imaging for Aerosol Deposition Assessment of Orally Inhaled Products. J Aerosol Med Pulm Drug Deliv 2012; 25 Suppl 1:S10-28. [DOI: 10.1089/jamp.2012.1su4] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Stephen Newman
- Scientific Consultant, Hunstanton, Norfolk, United Kingdom
| | - William D. Bennett
- Department of Medicine, Department of Pulmonary Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Martyn Biddiscombe
- Nuclear Medicine Department, Royal Brompton Hospital, Sydney Street, London, United Kingdom
| | - Sunalene G. Devadason
- School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia
| | - Myrna B. Dolovich
- Faculty of Sciences, Michael de Groote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - John Fleming
- University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | | | | | - Philip J. Kuehl
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Beth L. Laube
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Glyn Taylor
- Cardiff Scintigraphics and Welsh School of Pharmacy, Cardiff, United Kingdom
| | - Omar S. Usmani
- Airway Disease Section, National Heart and Lung Institute, Imperial College London and Royal Brompton Hospital, London, United Kingdom
| | - Kirby L. Zeman
- Center for Environmental Medicine, Asthma and Lung Biology, University of North Carolina, Chapel Hill, North Carolina
| |
Collapse
|
14
|
Fleming J, Bailey DL, Chan HK, Conway J, Kuehl PJ, Laube BL, Newman S. Standardization of Techniques for Using Single-Photon Emission Computed Tomography (SPECT) for Aerosol Deposition Assessment of Orally Inhaled Products. J Aerosol Med Pulm Drug Deliv 2012; 25 Suppl 1:S29-51. [DOI: 10.1089/jamp.2012.1su5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- John Fleming
- Respiratory Biomedical Research Unit, University Hospital Southampton, NHS Foundation Trust, Southampton, United Kingdom
| | | | - Hak-Kim Chan
- Advanced Drug Delivery Group, The University of Sydney, New South Wales, Australia
| | - Joy Conway
- Respiratory Biomedical Research Unit, University Hospital Southampton, NHS Foundation Trust, Southampton, United Kingdom
- School of Health Sciences, University of Southampton, Southampton, United Kingdom
| | - Philip J. Kuehl
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Beth L. Laube
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Stephen Newman
- Scientific Consultant, Hunstanton, Norfolk, United Kingdom
| |
Collapse
|
15
|
Conway J. Lung imaging - two dimensional gamma scintigraphy, SPECT, CT and PET. Adv Drug Deliv Rev 2012; 64:357-68. [PMID: 22310158 DOI: 10.1016/j.addr.2012.01.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/18/2012] [Accepted: 01/24/2012] [Indexed: 12/17/2022]
Abstract
This review will cover the principles of imaging the deposition of inhaled drugs and some of the state-of-the art imaging techniques being used today. Aerosol deposition can be imaged and quantified by the addition of a radiolabel to the aerosol formulation. The subsequent imaging of the inhaled deposition pattern can be acquired by different imaging techniques. Specifically, this review will focus on the use of two-dimensional planar, gamma scintigraphy, SPECT, CT and PET. This review will look at how these imaging techniques are used to investigate the mechanisms of drug delivery in the lung and how the lung anatomy and physiology have the potential to alter therapeutic outcomes.
Collapse
Affiliation(s)
- Joy Conway
- Faculty of Health Sciences, University of Southampton, Southampton General Hospital, UK.
| |
Collapse
|
16
|
Newman S, Fleming J. Challenges in assessing regional distribution of inhaled drug in the human lungs. Expert Opin Drug Deliv 2011; 8:841-55. [PMID: 21554149 DOI: 10.1517/17425247.2011.577063] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Both the total amount of drug deposited in the lungs (whole lung deposition) and the amount deposited in different lung regions (regional lung deposition) are potentially important factors that determine the safety and efficacy of inhaled drugs. Radionuclide imaging is well established for quantifying the whole lung deposition of inhaled drugs, but the assessment of regional lung deposition is less straightforward, because of the complex nature of the lung anatomy. AREAS COVERED This review describes the challenges and problems associated with quantifying regional lung deposition by the two-dimensional (2D) radionuclide imaging method of gamma scintigraphy, and by the three-dimensional (3D) radionuclide imaging methods of single-photon-emission computed tomography (SPECT) and positron-emission tomography (PET). The advantages and disadvantages of each method for assessing regional lung deposition are discussed. EXPERT OPINION Owing to its 2D nature, gamma scintigraphy provides limited information about regional lung deposition. SPECT provides regional lung deposition data in three dimensions, but usually involves a (99m)Tc radiolabel. PET enables the regional lung deposition of radiolabeled drug molecules to be quantified in three dimensions, but poses the greatest logistical and technical difficulties. Despite their more challenging nature, 3D imaging methods should be considered as an alternative to gamma scintigraphy whenever the determination of regional lung deposition of pharmaceutical aerosols is a major study objective.
Collapse
|
17
|
Ma B, Darquenne C. Aerosol deposition characteristics in distal acinar airways under cyclic breathing conditions. J Appl Physiol (1985) 2011; 110:1271-82. [PMID: 21330617 DOI: 10.1152/japplphysiol.00735.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Although the major mechanisms of aerosol deposition in the lung are known, detailed quantitative data in anatomically realistic models are still lacking, especially in the acinar airways. In this study, an algorithm was developed to build multigenerational three-dimensional models of alveolated airways with arbitrary bifurcation angles and spherical alveolar shape. Using computational fluid dynamics, the deposition of 1- and 3-μm aerosol particles was predicted in models of human alveolar sac and terminal acinar bifurcation under rhythmic wall motion for two breathing conditions (functional residual capacity = 3 liter, tidal volume = 0.5 and 0.9 liter, breathing period = 4 s). Particles entering the model during one inspiration period were tracked for multiple breathing cycles until all particles deposited or escaped from the model. Flow recirculation inside alveoli occurred only during transition between inspiration and expiration and accounted for no more than 1% of the whole cycle. Weak flow irreversibility and convective transport were observed in both models. The average deposition efficiency was similar for both breathing conditions and for both models. Under normal gravity, total deposition was ~33 and 75%, of which ~67 and 96% occurred during the first cycle, for 1- and 3-μm particles, respectively. Under zero gravity, total deposition was ~2-5% for both particle sizes. These results support previous findings that gravitational sedimentation is the dominant deposition mechanism for micrometer-sized aerosols in acinar airways. The results also showed that moving walls and multiple breathing cycles are needed for accurate estimation of aerosol deposition in acinar airways.
Collapse
Affiliation(s)
- Baoshun Ma
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0931, USA
| | | |
Collapse
|
18
|
Evaluation of an uncollimated printed paper transmission source used under scatter limiting conditions. Phys Med 2011; 27:11-20. [DOI: 10.1016/j.ejmp.2010.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 12/14/2009] [Accepted: 01/27/2010] [Indexed: 11/18/2022] Open
|
19
|
Fleming J, Conway J, Majoral C, Tossici-Bolt L, Katz I, Caillibotte G, Perchet D, Pichelin M, Muellinger B, Martonen T, Kroneberg P, Apiou-Sbirlea G. The use of combined single photon emission computed tomography and X-ray computed tomography to assess the fate of inhaled aerosol. J Aerosol Med Pulm Drug Deliv 2010; 24:49-60. [PMID: 21166585 DOI: 10.1089/jamp.2010.0843] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Gamma camera imaging is widely used to assess pulmonary aerosol deposition. Conventional planar imaging provides limited information on its regional distribution. In this study, single photon emission computed tomography (SPECT) was used to describe deposition in three dimensions (3D) and combined with X-ray computed tomography (CT) to relate this to lung anatomy. Its performance was compared to planar imaging. METHODS Ten SPECT/CT studies were performed on five healthy subjects following carefully controlled inhalation of radioaerosol from a nebulizer, using a variety of inhalation regimes. The 3D spatial distribution was assessed using a central-to-peripheral ratio (C/P) normalized to lung volume and for the right lung was compared to planar C/P analysis. The deposition by airway generation was calculated for each lung and the conducting airways deposition fraction compared to 24-h clearance. RESULTS The 3D normalized C/P ratio correlated more closely with 24-h clearance than the 2D ratio for the right lung [coefficient of variation (COV), 9% compared to 15% p < 0.05]. Analysis of regional distribution was possible for both lungs in 3D but not in 2D due to overlap of the stomach on the left lung. The mean conducting airways deposition fraction from SPECT for both lungs was not significantly different from 24-h clearance (COV 18%). Both spatial and generational measures of central deposition were significantly higher for the left than for the right lung. CONCLUSIONS Combined SPECT/CT enabled improved analysis of aerosol deposition from gamma camera imaging compared to planar imaging. 3D radionuclide imaging combined with anatomical information from CT and computer analysis is a useful approach for applications requiring regional information on deposition.
Collapse
Affiliation(s)
- John Fleming
- Department of Medical Physics and Bioengineering, Southampton University Hospitals, NHS Trust, Southampton, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Möller W, Felten K, Meyer G, Meyer P, Seitz J, Kreyling WG. Corrections in Dose Assessment of99mTc Radiolabeled Aerosol Particles Targeted to Central Human Airways Using Planar Gamma Camera Imaging. J Aerosol Med Pulm Drug Deliv 2009; 22:45-54. [DOI: 10.1089/jamp.2007.0664] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Winfried Möller
- Helmholtz Zentrum München–German Research Center for Environmental Health, Clinical Cooperation Group Inflammatory Lung Diseases, Institute for Inhalation Biology, and Focus Network Aerosols and Health, Gauting and Neuherberg, Germany
| | - Kathrin Felten
- Helmholtz Zentrum München–German Research Center for Environmental Health, Clinical Cooperation Group Inflammatory Lung Diseases, Institute for Inhalation Biology, and Focus Network Aerosols and Health, Gauting and Neuherberg, Germany
| | - Gabriele Meyer
- Asklepios Hospital for Respiratory Diseases, Gauting, Germany
| | - Peter Meyer
- Helmholtz Zentrum München–German Research Center for Environmental Health, Clinical Cooperation Group Inflammatory Lung Diseases, Institute for Inhalation Biology, and Focus Network Aerosols and Health, Gauting and Neuherberg, Germany
- Asklepios Hospital for Respiratory Diseases, Gauting, Germany
| | | | - Wolfgang G. Kreyling
- Helmholtz Zentrum München–German Research Center for Environmental Health, Clinical Cooperation Group Inflammatory Lung Diseases, Institute for Inhalation Biology, and Focus Network Aerosols and Health, Gauting and Neuherberg, Germany
| |
Collapse
|
21
|
Möller W, Meyer G, Kreyling WG. Advances in lung imaging techniques for the treatment of respiratory disease. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.ddstr.2008.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
22
|
Tossici-Bolt L, Fleming JS, Conway JH, Martonen TB. Analytical technique to recover the third dimension in planar imaging of inhaled aerosols: (1) impact on spatial quantification. ACTA ACUST UNITED AC 2007; 19:565-79. [PMID: 17196084 DOI: 10.1089/jam.2006.19.565] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
An analytical algorithm is described for converting planar scintigraphic images of aerosol distributions in the lungs to an equivalent three-dimensional (3D) representation. The recovery of volumetric information should benefit regional quantification. The technique has been validated using simulated planar images of eleven known aerosol distributions in ten realistic lungs. Global and regional 3D parameters, such as the total activity deposition (A), the penetration index (PI) and the relative penetration index (rPI), were quantified on the planar images and on their 3D representation. Random and systematic errors of the estimation were measured. Finally, the performance of planar imaging was compared with that of single-photon emission computed tomography (SPECT). SPECT images were simulated for the same aerosol distributions in the same subjects and quantified for A, PI, and rPI. The systematic errors in A, PI and rPI obtained from planar imaging were 8.9%, 64.8%, and 54.1%, respectively, using the two-dimensional (2D) analysis; they improved significantly to 4.4%, 19.0%, and 25.5% with the 3D analysis (p < 0.01). The corresponding values for SPECT were 5.2%, 9.8%, and 15.7%, significantly better for PI and rPI (p < 0.01). The random errors of A were similar for all techniques being about 5%; those of PI and rPI measurements were significantly higher for planar imaging (<or=14%) than SPECT (<or=8%). In conclusion, 3D spatial parameters can be derived from planar imaging that are significantly more accurate in characterizing different aerosol depositions than their 2D counterpart. However, the errors remain significantly higher than with SPECT.
Collapse
Affiliation(s)
- Livia Tossici-Bolt
- Department of Medical Physics and Bioengineering, Southampton University Hospital NHS Trust, Southampton, United Kingdom.
| | | | | | | |
Collapse
|
23
|
Fleming JS, Epps BP, Conway JH, Martonen TB. Comparison of SPECT aerosol deposition data with a human respiratory tract model. ACTA ACUST UNITED AC 2007; 19:268-78. [PMID: 17034303 DOI: 10.1089/jam.2006.19.268] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Three-dimensional (3D) radionuclide imaging provides detailed information on the distribution of inhaled aerosol material within the body. Analysis of the data can provide estimates of the deposition per airway generation. In this study, two different nebulizers have been used to deliver radiolabeled aerosols of different particle size to 12 human subjects. Medical imaging has been used to assess the deposition in the body. The deposition pattern has also been estimated using the International Commission on Radiological Protection (ICRP) empirical model and compared to values obtained by experiment. The results showed generally good agreement between model and experiment for both aerosols for the deposition in the extrathoracic and conducting airways. However, there were significant differences in the fate of the remainder of the aerosol between the amount deposited in the alveolar region and that exhaled. The inter-subject variability of deposition predicted by the model was significantly less than that measured, for all regions of the body. The model predicted quite well the differences in deposition distribution pattern between the two aerosols. In conclusion, this study has shown that the ICPR model of inhaled aerosol deposition shows areas of good agreement with results from experiment. However, there are also areas of disagreement, which may be explained by hygroscopic particle growth and individual variation in airway anatomy.
Collapse
Affiliation(s)
- John S Fleming
- Department of Medical Physics and Bioengineering, Southampton University Hospitals NHS Trust, Southampton, United Kingdom.
| | | | | | | |
Collapse
|
24
|
Fleming JS, Quint M, Bolt L, Martonen TB, Conway JH. Comparison of SPECT aerosol deposition data with twenty-four-hour clearance measurements. ACTA ACUST UNITED AC 2007; 19:261-7. [PMID: 17034302 DOI: 10.1089/jam.2006.19.261] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Three-dimensional (3D) radionuclide imaging provides detailed information on the distribution of inhaled aerosol material within the body. Analysis of the data can provide estimates of the deposition per airway generation. Information on regional distribution of deposited aerosol can also be obtained from 24-hour clearance measurements. In this study, a nebulizer was used to deliver a radiolabeled aerosol to nine human subjects. Single photon emission computed tomography (SPECT) has been used to assess the distribution of aerosol deposition per airway generation. The deposition pattern was also estimated using measurements of the aerosol remaining in the lung 24 h after inhalation. The error in the SPECT value was assessed by simulation and that in the 24-h clearance value by repeat analysis. The mean fraction of lung deposition in the conducting airway (CADF) from SPECT was 0.21. The corresponding 24-h clearance value was 0.23. These values were not significantly different. There was a weak but non-significant correlation between the SPECT and 24-h measurements (r = 0.49). The standard error of the difference was 0.11. The corresponding errors on the SPECT and 24-h clearance measurements were 0.04 and 0.05, respectively. There was no systematic difference between the values of conducting airways deposition obtained from 24-h measurements and SPECT. However, there were random differences on individual subjects, which were larger than the estimated measurement errors.
Collapse
Affiliation(s)
- John S Fleming
- Department of Medical Physics and Bioengineering, Southampton University Hospitals NHS Trust, Southampton, United Kingdom.
| | | | | | | | | |
Collapse
|
25
|
Fleming JS, Sauret V, Conway JH, Martonen TB. Validation of the Conceptual Anatomical Model of the Lung Airway. ACTA ACUST UNITED AC 2004; 17:260-9. [PMID: 15625818 DOI: 10.1089/jam.2004.17.260] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The conceptual anatomical model of the lung airway considers each lung volume divided into ten concentric shells. It specifies the volume of each airway generation in each shell, using Weibel morphometry. This study updates and validates the model and evaluates the errors obtained when using it to estimate inhaled aerosol deposition per generation from spatial imaging data. A comparison of different airway models describing the volume per generation, including data from CT images of a lung cast and a human subject, was performed. A revised version of the conceptual model was created, using the average volume per generation from these data. The new model was applied to derive the aerosol deposition per generation from 24 single photon emission computed tomography (SPECT) studies. Analysis errors were assessed by applying the same calculations but using airway models based on the minimum and maximum volumes per generation. The mean shell position of each generation in the average model was not significantly different from either CT model. However there were differences between the volumes per generation of the different models. The root mean square differences between bronchial airways deposition fraction (generations 2-8) obtained from the maximum and minimum models compared to the new average model was 0.66 percentage points (14%). For the conducting airways deposition fraction (generations 2-15) this was 1.66 percentage points (12%). The conceptual model is consistent with CT measurements of airway geometry. The errors resulting from using a generic airway model to interpret 3D radionuclide image data have been defined.
Collapse
Affiliation(s)
- John S Fleming
- Department of Medical Physics and Bioengineering, Southampton University Hospitals NHS Trust, United Kingdom.
| | | | | | | |
Collapse
|
26
|
Itti E, Fauroux B, Pigeot J, Isabey D, Clement A, Evangelista E, Harf A, Meignan M. Quantitative lung perfusion scan as a predictor of aerosol distribution heterogeneity and disease severity in children with cystic fibrosis. Nucl Med Commun 2004; 25:563-9. [PMID: 15167515 DOI: 10.1097/01.mnm.0000126508.96340.1d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The assessment of lung ventilation by radionuclide imaging has proved useful for the optimization of aerosol therapy in children with cystic fibrosis. Further analysis of lung perfusion may provide additional information. METHODS Quantitative analysis of regional lung aerosol distribution (Tc phytates) and perfusion (Tc macroaggregates) homogeneity was performed in 18 children with cystic fibrosis, using the third and fourth spatial moments (skew and Kurtosis) of count distribution. Patients were chosen from a prospective study whose goal was to compare the efficacy of two nebulization methods of a radiolabelled aerosol: one session involved a nebulizer activated by patient inspiratory flow (control session), whereas the other involved a nebulizer powered by a pressure support device (PS session). RESULTS Quantitative regional distribution of perfusion was similar to aerosol distribution, although skew and Kurtosis were lower, indicating better homogeneity. Perfusion skew was inversely correlated with pulmonary volumes and Shwachman score, even more significantly than ventilation skew. Using receiver operating characteristic curve analysis, a perfusion skew threshold of 0.67 was predictive of disease severity (FEV1 > or =60% or FEV1 <60%) with 86% sensitivity and 91% specificity. Furthermore, same skew threshold allowed the identification of patients who were 'PS responders' (greater amount of radioactivity deposited after the PS session) or 'PS non-responders' with 80% sensitivity and 77% specificity. CONCLUSION Quantification of regional lung perfusion is easy to perform and heterogeneity of the distribution is closely correlated to disease severity. Moreover, perfusion skew can identify patients who are likely to benefit from pressure support (to optimize aerosol therapy) and may be helpful for orienting potential non-responders towards alternative therapies.
Collapse
Affiliation(s)
- Emmanuel Itti
- Department of Nuclear Medicine, H. Mondor Hospital, Assistance Publique - Hôpitaux de Paris, Paris XII University, Créteil, France.
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Salvi S. Ambient particulate air pollution and childhood asthma exacerbations. Ann Allergy Asthma Immunol 2003; 91:321-3. [PMID: 14582808 DOI: 10.1016/s1081-1206(10)61675-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|