1
|
West CM, Wearing OH, Rhem RG, Scott GR. Pulmonary hypertension is attenuated and ventilation-perfusion matching is maintained during chronic hypoxia in deer mice native to high altitude. Am J Physiol Regul Integr Comp Physiol 2021; 320:R800-R811. [PMID: 33826424 DOI: 10.1152/ajpregu.00282.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hypoxia at high altitude can constrain metabolism and performance and can elicit physiological adjustments that are deleterious to health and fitness. Hypoxic pulmonary hypertension is a particularly serious and maladaptive response to chronic hypoxia, which results from vasoconstriction and pathological remodeling of pulmonary arteries, and can lead to pulmonary edema and right ventricle hypertrophy. We investigated whether deer mice (Peromyscus maniculatus) native to high altitude have attenuated this maladaptive response to chronic hypoxia and whether evolved changes or hypoxia-induced plasticity in pulmonary vasculature might impact ventilation-perfusion (V-Q) matching in chronic hypoxia. Deer mouse populations from both high and low altitudes were born and raised to adulthood in captivity at sea level, and various aspects of lung function were measured before and after exposure to chronic hypoxia (12 kPa O2, simulating the O2 pressure at 4,300 m) for 6-8 wk. In lowlanders, chronic hypoxia increased right ventricle systolic pressure (RVSP) from 14 to 19 mmHg (P = 0.001), in association with thickening of smooth muscle in pulmonary arteries and right ventricle hypertrophy. Chronic hypoxia also impaired V-Q matching in lowlanders (measured at rest using SPECT-CT imaging), as reflected by increased log SD of the perfusion distribution (log SDQ) from 0.55 to 0.86 (P = 0.031). In highlanders, chronic hypoxia had attenuated effects on RVSP and no effects on smooth muscle thickness, right ventricle mass, or V-Q matching. Therefore, evolved changes in lung function help attenuate maladaptive plasticity and contribute to hypoxia tolerance in high-altitude deer mice.
Collapse
Affiliation(s)
- Claire M West
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Oliver H Wearing
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Rod G Rhem
- Division of Respirology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
2
|
Bajc M, Lindqvist A. Ventilation/Perfusion SPECT Imaging Diagnosing PE and Other Cardiopulmonary Diseases. Clin Nucl Med 2020. [DOI: 10.1007/978-3-030-39457-8_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
3
|
Bajc M, Schümichen C, Grüning T, Lindqvist A, Le Roux PY, Alatri A, Bauer RW, Dilic M, Neilly B, Verberne HJ, Delgado Bolton RC, Jonson B. EANM guideline for ventilation/perfusion single-photon emission computed tomography (SPECT) for diagnosis of pulmonary embolism and beyond. Eur J Nucl Med Mol Imaging 2019; 46:2429-2451. [PMID: 31410539 PMCID: PMC6813289 DOI: 10.1007/s00259-019-04450-0] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/17/2019] [Indexed: 12/18/2022]
Abstract
These guidelines update the previous EANM 2009 guidelines on the diagnosis of pulmonary embolism (PE). Relevant new aspects are related to (a) quantification of PE and other ventilation/perfusion defects; (b) follow-up of patients with PE; (c) chronic PE; and (d) description of additional pulmonary physiological changes leading to diagnoses of left ventricular heart failure (HF), chronic obstructive pulmonary disease (COPD) and pneumonia. The diagnosis of PE should be reported when a mismatch of one segment or two subsegments is found. For ventilation, Technegas or krypton gas is preferred over diethylene triamine pentaacetic acid (DTPA) in patients with COPD. Tomographic imaging with V/PSPECT has higher sensitivity and specificity for PE compared with planar imaging. Absence of contraindications makes V/PSPECT an essential method for the diagnosis of PE. When V/PSPECT is combined with a low-dose CT, the specificity of the test can be further improved, especially in patients with other lung diseases. Pitfalls in V/PSPECT interpretation are discussed. In conclusion, V/PSPECT is strongly recommended as it accurately establishes the diagnosis of PE even in the presence of diseases like COPD, HF and pneumonia and has no contraindications.
Collapse
Affiliation(s)
- Marika Bajc
- Department of Clinical Sciences, Clinical Physiology and Nuclear Medicine, University of Lund, Lund, Sweden.
| | - Carl Schümichen
- University of Rostock, Formerly Clinic for Nuclear Medicine, Rostock, Germany
| | - Thomas Grüning
- Department of Nuclear Medicine, University Hospitals Plymouth, Plymouth, UK
| | - Ari Lindqvist
- Research Unit of Pulmonary Diseases, Clinical Research Institute, HUS Helsinki University Hospital, Helsinki, Finland
| | | | - Adriano Alatri
- Division of Angiology, Heart and Vessel Department, Lausanne University Hospital, Lausanne, Switzerland
| | - Ralf W Bauer
- RNS Gemeinschaftspraxis, Wiesbaden, Germany
- Department of Diagnostic and Interventional Radiology, Goethe University Frankfurt (Main), Frankfurt, Germany
| | - Mirza Dilic
- Clinic of Heart and Blood Vessel Disease, Clinical Center University of Sarajevo, Sarajevo, Bosnia and Herzegovina
| | - Brian Neilly
- Department of Nuclear Medicine, Royal Infirmary, Glasgow, UK
| | - Hein J Verberne
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, Location AMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Roberto C Delgado Bolton
- Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, University Hospital San Pedro and Centre for Biomedical Research of La Rioja (CIBIR), Logroño, La Rioja, Spain
| | - Bjorn Jonson
- Department of Clinical Sciences, Clinical Physiology and Nuclear Medicine, University of Lund, Lund, Sweden
| |
Collapse
|
4
|
Bajc M, Lindqvist A. Ventilation/Perfusion SPECT Imaging—Diagnosing Other Cardiopulmonary Diseases Beyond Pulmonary Embolism. Semin Nucl Med 2019; 49:4-10. [DOI: 10.1053/j.semnuclmed.2018.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
5
|
Preissner M, Murrie RP, Bresee C, Carnibella RP, Fouras A, Weir EK, Dubsky S, Pinar IP, Jones HD. Application of a novel in vivo imaging approach to measure pulmonary vascular responses in mice. Physiol Rep 2018; 6:e13875. [PMID: 30284390 PMCID: PMC6170880 DOI: 10.14814/phy2.13875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 12/19/2022] Open
Abstract
Noninvasive imaging of the murine pulmonary vasculature is challenging due to the small size of the animal, limits of resolution of the imaging technology, terminal nature of the procedure, or the need for intravenous contrast. We report the application of laboratory-based high-speed, high-resolution x-ray imaging, and image analysis to detect quantitative changes in the pulmonary vascular tree over time in the same animal without the need for intravenous contrast. Using this approach, we detected an increased number of vessels in the pulmonary vascular tree of animals after 30 min of recovery from a brief exposure to inspired gas with 10% oxygen plus 5% carbon dioxide (mean ± standard deviation: 2193 ± 382 at baseline vs. 6177 ± 1171 at 30 min of recovery; P < 0.0001). In a separate set of animals, we showed that the total pulmonary blood volume increased (P = 0.0412) while median vascular diameter decreased from 0.20 mm (IQR: 0.15-0.28 mm) to 0.18 mm (IQR: 0.14-0.26 mm; P = 0.0436) over the respiratory cycle from end-expiration to end-inspiration. These findings suggest that the noninvasive, nonintravenous contrast imaging approach reported here can detect dynamic responses of the murine pulmonary vasculature and may be a useful tool in studying these responses in models of disease.
Collapse
Affiliation(s)
- Melissa Preissner
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Rhiannon P. Murrie
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Catherine Bresee
- Cedars‐Sinai Medical CenterBiostatistics & Bioinformatics Research InstituteLos AngelesCalifornia
| | | | - Andreas Fouras
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
- 4Dx LimitedMelbourneVictoriaAustralia
- Department of Biomedical SciencesCedars‐Sinai Medical CenterBiomedical Imaging Research InstituteLos AngelesCalifornia
| | - E. Kenneth Weir
- Department of MedicineUniversity of MinnesotaMinneapolisMinnesota
| | - Stephen Dubsky
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Isaac P. Pinar
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Heather D. Jones
- Department of Biomedical SciencesCedars‐Sinai Medical CenterBiomedical Imaging Research InstituteLos AngelesCalifornia
| |
Collapse
|
6
|
Pinar IP, Jones HD. Novel imaging approaches for small animal models of lung disease (2017 Grover Conference series). Pulm Circ 2018; 8:2045894018762242. [PMID: 29480066 PMCID: PMC5888832 DOI: 10.1177/2045894018762242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Imaging in small animal models of lung disease is challenging, as existing technologies are limited either by resolution or by the terminal nature of the imaging approach. Here, we describe the current state of small animal lung imaging, the technological advances of laboratory-sourced phase contrast X-ray imaging, and the application of this novel technology and its attendant image analysis techniques to the in vivo imaging of the large airways and pulmonary vasculature in murine models of lung health and disease.
Collapse
Affiliation(s)
- Isaac P Pinar
- 1 Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.,2 Division of Biological Engineering, Faculty of Engineering, Monash University, Melbourne, VIC, Australia
| | - Heather D Jones
- 3 Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| |
Collapse
|
7
|
Bajc M, Chen Y, Wang J, Li XY, Shen WM, Wang CZ, Huang H, Lindqvist A, He XY. Identifying the heterogeneity of COPD by V/P SPECT: a new tool for improving the diagnosis of parenchymal defects and grading the severity of small airways disease. Int J Chron Obstruct Pulmon Dis 2017; 12:1579-1587. [PMID: 28603413 PMCID: PMC5457181 DOI: 10.2147/copd.s131847] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Introduction Airway obstruction and possible concomitant pulmonary diseases in COPD cannot be identified conventionally with any single diagnostic tool. We aimed to diagnose and grade COPD severity and identify pulmonary comorbidities associated with COPD with ventilation/perfusion single-photon emission computed tomography (V/P SPECT) using Technegas as the functional ventilation imaging agent. Methods 94 COPD patients (aged 43–86 years, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages I–IV) were examined with V/P SPECT and spirometry. Ventilation and perfusion defects were analyzed blindly according to the European guidelines. Penetration grade of Technegas in V SPECT measured the degree of obstructive small airways disease. Total preserved lung function and penetration grade of Technegas in V SPECT were assessed by V/P SPECT and compared to GOLD stages and spirometry. Results Signs of small airway obstruction in the ventilation SPECT images were found in 92 patients. Emphysema was identified in 81 patients. Two patients had no signs of COPD, but both of them had a pulmonary embolism, and in one of them we also suspected a lung tumor. The penetration grade of Technegas in V SPECT and total preserved lung function correlated significantly to GOLD stages (r=0.63 and −0.60, respectively, P<0.0001). V/P SPECT identified pulmonary embolism in 30 patients (32%). A pattern typical for heart failure was present in 26 patients (28%). Parenchymal changes typical for pneumonia or lung tumor were present in several cases. Conclusion V/P SPECT, using Technegas as the functional ventilation imaging agent, is a new tool to diagnose COPD and to grade its severity. Additionally, it revealed heterogeneity of COPD caused by pulmonary comorbidities. The characteristics of these comorbidities suggest their significant impact in clarifying symptoms, and also their influence on the prognosis.
Collapse
Affiliation(s)
- M Bajc
- Department of Clinical Science Physiology and Nuclear Medicine, Skåne University Hospital, Lund, Sweden
| | - Y Chen
- Respiratory Department, Changzheng Hospital, Shanghai
| | - J Wang
- Respiratory Department, Xinqiao Hospital, Chongqing
| | - X Y Li
- Respiratory Department, Huadong Hospital, Shanghai, China
| | - W M Shen
- Respiratory Department, Huadong Hospital, Shanghai, China
| | - C Z Wang
- Respiratory Department, Xinqiao Hospital, Chongqing
| | - H Huang
- Respiratory Department, Changzheng Hospital, Shanghai
| | - A Lindqvist
- Department of Pulmonary Medicine, Heart and Lung Center, Helsinki University Hospital and Helsinki University, Helsinki, Finland
| | - X Y He
- Suzhou University Affiliated Tumor Hospital, Wuxi, China
| |
Collapse
|
8
|
Dubsky S, Fouras A. Imaging regional lung function: a critical tool for developing inhaled antimicrobial therapies. Adv Drug Deliv Rev 2015; 85:100-9. [PMID: 25819486 DOI: 10.1016/j.addr.2015.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 12/11/2022]
Abstract
Alterations in regional lung function due to respiratory infection have a significant effect on the deposition of inhaled treatments. This has consequences for treatment effectiveness and hence recovery of lung function. In order to advance our understanding of respiratory infection and inhaled treatment delivery, we must develop imaging techniques that can provide regional functional measurements of the lung. In this review, we explore the role of functional imaging for the assessment of respiratory infection and development of inhaled treatments. We describe established and emerging functional lung imaging methods. The effect of infection on lung function is described, and the link between regional disease, function, and inhaled treatments is discussed. The potential for lung function imaging to provide unique insights into the functional consequences of infection, and its treatment, is also discussed.
Collapse
Affiliation(s)
- Stephen Dubsky
- Department of Mechanical & Aerospace Engineering, Monash University, Victoria 3800, Australia.
| | - Andreas Fouras
- Department of Mechanical & Aerospace Engineering, Monash University, Victoria 3800, Australia.
| |
Collapse
|
9
|
Jögi J, Markstad H, Tufvesson E, Bjermer L, Bajc M. The added value of hybrid ventilation/perfusion SPECT/CT in patients with stable COPD or apparently healthy smokers. Cancer-suspected CT findings in the lungs are common when hybrid imaging is used. Int J Chron Obstruct Pulmon Dis 2014; 10:25-30. [PMID: 25565797 PMCID: PMC4279608 DOI: 10.2147/copd.s73423] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ventilation/perfusion (V/P) single-photon emission computed tomography (SPECT) is recognized as a diagnostic method with potential beyond the diagnosis of pulmonary embolism. V/P SPECT identifies functional impairment in diseases such as heart failure (HF), pneumonia, and chronic obstructive pulmonary disease (COPD). The development of hybrid SPECT/computed tomography (CT) systems, combining functional with morphological imaging through the addition of low-dose CT (LDCT), may be useful in COPD, as these patients are prone to lung cancer and other comorbidities. The aim of this study was to investigate the added value of LDCT among healthy smokers and patients with stable COPD, when examined with V/P SPECT/CT hybrid imaging. Sixty-nine subjects, 55 with COPD (GOLD I-IV) and 14 apparently healthy smokers, were examined with V/P SPECT and LDCT hybrid imaging. Spirometry was used to verify COPD grade. Only one apparently healthy smoker and three COPD patients had a normal or nearly normal V/P SPECT. All other patients showed various degrees of airway obstruction, even when spirometry was normal. The same interpretation was reached on both modalities in 39% of the patients. LDCT made V/P SPECT interpretation more certain in 9% of the patients and, in 52%, LDCT provided additional diagnoses. LDCT better characterized the type of emphysema in 12 patients. In 19 cases, tumor-suspected changes were reported. Three of these 19 patients (ie, 4.3% of all subjects) were in the end confirmed to have lung cancer. The majority of LDCT findings were not regarded as clinically significant. V/P SPECT identified perfusion patterns consistent with decompensated left ventricular HF in 14 COPD patients. In 16 patients (23%), perfusion defects were observed. HF and perfusion defects were not recognized with LDCT. In COPD patients and long-time smokers, hybrid imaging had added value compared to V/P SPECT alone, by identifying patients with lung malignancy and more clearly identifying emphysema. V/P SPECT visualizes comorbidities to COPD not seen with LDCT, such as pulmonary embolism and left ventricular HF.
Collapse
Affiliation(s)
- Jonas Jögi
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital and Lund University, Lund, Sweden
| | - Hanna Markstad
- Department of Radiology, Skåne University Hospital and Lund University, Lund, Sweden
| | - Ellen Tufvesson
- Department of Respiratory Medicine and Allergology, Skåne University Hospital and Lund University, Lund, Sweden
| | - Leif Bjermer
- Department of Respiratory Medicine and Allergology, Skåne University Hospital and Lund University, Lund, Sweden
| | - Marika Bajc
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital and Lund University, Lund, Sweden
| |
Collapse
|
10
|
Norberg P, Persson HL, Schmekel B, Carlsson GA, Wahlin K, Sandborg M, Gustafsson A. Does quantitative lung SPECT detect lung abnormalities earlier than lung function tests? Results of a pilot study. EJNMMI Res 2014; 4:39. [PMID: 26055938 PMCID: PMC4884006 DOI: 10.1186/s13550-014-0039-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/02/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heterogeneous ventilation in lungs of individuals with allergies, cigarette smokers, asthmatics and chronic obstructive pulmonary disease (COPD) patients has been demonstrated using imaging modalities such as positron emission tomography (PET), magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT). These individuals suffer from narrow and/or closed airways to various extents. By calculating regional heterogeneity in lung ventilation SPECT images as the coefficient of variation (CV) in small elements of the lung, heterogeneity maps and CV-density curves can be generated and used to quantitatively measure heterogeneity. This work explores the potential to use such measurements to detect mild ventilation heterogeneities in lung-healthy subjects. METHOD Fourteen healthy subjects without documented lung disease or respiratory symptoms, and two patients with documented airway disease, inhaled on average approximately 90 MBq (99m)Tc-Technegas immediately prior to the 20-min SPECT acquisition. Variation in activity uptake between subjects was compensated for in resulting CV values. The area under the compensated CV density curve (AUC), for CV values greater than a threshold value CVT, AUC(CV > CVT), was used as the measure of ventilation heterogeneity. RESULTS Patients with lung function abnormalities, according to lung function tests, generated higher AUC(CV > 20%) values compared to healthy subjects (p = 0.006). Strong linear correlations with the AUC(CV > 20%) values were found for age (p = 0.006) and height (p = 0.001). These demonstrated that ventilation heterogeneities increased with age and that they depend on lung size. Strong linear correlations were found for the lung function value related to indices of airway closure/air trapping, residual volume/total lung capacity (RV/TLC; p = 0.009), and diffusion capacity of the lung for carbon monoxide adjusted for haemoglobin concentration in the blood (DLCOc; p = 0.009), a value partly related to supposed ventilation/perfusion mismatch. These findings support the association between conventional lung function tests and the AUC(CV > 20%) value. CONCLUSIONS Among the healthy subjects, there is a group with increased AUC(CV > 20%) values, but with normal lung function tests, which implies that it might be possible to differentiate ventilation heterogeneities earlier in a disease process than by lung function tests.
Collapse
Affiliation(s)
- Pernilla Norberg
- />Medical Radiation Physics, County Council of Östergötland, Linköping, 581 85 Sweden
- />Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, 581 83 Sweden
- />Department of Medical and Health Sciences, Linköping University, Linköping, 581 83 Sweden
| | - Hans Lennart Persson
- />Department of Respiratory Medicine and Department of Medical and Health Sciences, Linköping University, Linköping, 581 83 Sweden
| | - Birgitta Schmekel
- />Department of Clinical Physiology and Department of Medical and Health Sciences, Linköping University, Linköping, 581 83 Sweden
| | - Gudrun Alm Carlsson
- />Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, 581 83 Sweden
- />Department of Medical and Health Sciences, Linköping University, Linköping, 581 83 Sweden
| | - Karl Wahlin
- />Department of Computer and Information Science, Linköping University, Linköping, 581 83 Sweden
| | - Michael Sandborg
- />Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, 581 83 Sweden
- />Department of Medical and Health Sciences, Linköping University, Linköping, 581 83 Sweden
| | - Agnetha Gustafsson
- />Department of Medical Physics, Karolinska University Hospital, Huddinge, Stockholm 141 86 Sweden
| |
Collapse
|
11
|
Bajc M, Markstad H, Jarenbäck L, Tufvesson E, Bjermer L, Jögi J. Grading obstructive lung disease using tomographic pulmonary scintigraphy in patients with chronic obstructive pulmonary disease (COPD) and long-term smokers. Ann Nucl Med 2014; 29:91-9. [PMID: 25315109 PMCID: PMC4284371 DOI: 10.1007/s12149-014-0913-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/30/2014] [Indexed: 01/08/2023]
Abstract
UNLABELLED The severity of chronic obstructive lung disease (COPD) is defined by the degree of flow limitation measured as forced expiratory volume in 1 s, which mainly reflects impairment of large and intermediate airways. However, COPD is primarily a small airways disease. Therefore, better diagnostic tools are needed. Ventilation-Perfusion (V/P) SPECT is a sensitive method to detect obstructive lung changes but criteria for staging airway obstruction are missing. PURPOSE To define and validate criteria to stage COPD using V/P SPECT. METHOD 74 subjects (healthy non-smokers, healthy smokers or with stable COPD) were included. All were examined with V/P SPECT in a hybrid SPECT/CT system. Spirometry was performed and patients were evaluated with the clinical COPD questionnaire (CCQ). V/P SPECT was interpreted independently. Preserved lung function (%) was evaluated. The degree of airway obstruction on V/P SPECT was graded according to newly-developed grading criteria. The degree of airway obstruction was graded from normal (0) to severe (3). The airway obstructivity-grade and degree of preserved lung function were compared to GOLD, CCQ and LDCT emphysema extent. RESULTS Obstructivity-grade (r = 0.66, P < 0.001) and the degree of preserved lung function (r = -0.70, P < 0.001) both correlated to GOLD. Total preserved lung function decreased in relation to higher GOLD stage. There was a significant difference between healthy controls and apparently healthy long time smokers both regarding obstructivity-grade (P = 0.001) and preserved lung function (P < 0.001). Long-time smokers did not differ significantly from GOLD 1 COPD patients (P = 0.14 and P = 0.55 for obstructivity-grade and preserved lung function, respectively). However, patients in GOLD 1 differed in obstructivity-grade from non-smoking controls (P = 0.02). CONCLUSION Functional imaging with V/P SPECT enables standardized grading of airway obstruction as well as reduced lung function, both of which correlate with GOLD stage. V/P SPECT shows that long-term smokers in most cases have signs of ventilatory impairment and airway obstruction not shown by spirometry.
Collapse
Affiliation(s)
- Marika Bajc
- Department of Clinical Physiology and Nuclear Medicine, Department of Imaging and Physiology, Skåne University Hospital and Lund University, 22185, Lund, Sweden,
| | | | | | | | | | | |
Collapse
|
12
|
Jobse BN, McCurry CA, Morissette MC, Rhem RG, Stämpfli MR, Labiris NR. Impact of inflammation, emphysema, and smoking cessation on V/Q in mouse models of lung obstruction. Respir Res 2014; 15:42. [PMID: 24730756 PMCID: PMC4021179 DOI: 10.1186/1465-9921-15-42] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 04/01/2014] [Indexed: 01/05/2023] Open
Abstract
Background Chronic obstructive pulmonary disease (COPD) is known to greatly affect ventilation (V) and perfusion (Q) of the lung through pathologies such as inflammation and emphysema. However, there is little direct evidence regarding how these pathologies contribute to the V/Q mismatch observed in COPD and models thereof. Also, little is known regarding how smoking cessation affects V/Q relationships after inflammation and airspace enlargement have become established. To this end, we have quantified V/Q on a per-voxel basis using single photon emission computed tomography (SPECT) in mouse models of COPD and lung obstruction. Methods Three distinct murine models were used to investigate the impact of different pathologies on V/Q, as measured by SPECT. Lipopolysaccharide (LPS) was used to produce neutrophilic inflammation, porcine pancreatic elastase (PPE) was used to produce emphysema, and long-term cigarette smoke (CS) exposure and cessation were used to investigate the combination of these pathologies. Results CS exposure resulted in an increase in mononuclear cells and neutrophils, an increase in airspace enlargement, and an increase in V/Q mismatching. The inflammation produced by LPS was more robust and predominantly neutrophilic, compared to that of cigarette smoke; nevertheless, inflammation alone caused V/Q mismatching similar to that seen with long-term CS exposure. The emphysematous lesions caused by PPE administration were also capable of causing V/Q mismatch in the absence of inflammation. Following CS cessation, inflammatory cell levels returned to those of controls and, similarly, V/Q measures returned to normal despite evidence of persistent mild airspace enlargement. Conclusions Both robust inflammation and extensive airspace enlargement, on their own, were capable of producing V/Q mismatch. As CS cessation resulted in a return of V/Q mismatching and inflammatory cell counts to control levels, lung inflammation is likely a major contributor to V/Q mismatch observed in the cigarette smoke exposure model as well as in COPD patients. This return of V/Q mismatching to control values also took place in the presence of mild airspace enlargement, indicating that emphysematous lesions must be of a larger volume before affecting the lung significantly. Early smoking cessation is therefore critical before emphysema has an irreversible impact on gas exchange.
Collapse
Affiliation(s)
| | | | | | | | | | - Nancy Renée Labiris
- Department of Medicine, Division of Respirology, McMaster University, Hamilton, Canada.
| |
Collapse
|
13
|
Jobse BN, Rhem RG, Wang IQ, Counter WB, Stämpfli MR, Labiris NR. Detection of lung dysfunction using ventilation and perfusion SPECT in a mouse model of chronic cigarette smoke exposure. J Nucl Med 2013; 54:616-23. [PMID: 23397007 DOI: 10.2967/jnumed.112.111419] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Chronic obstructive pulmonary disease is a leading cause of morbidity and mortality worldwide. Exposure to cigarette smoke (CS) is a major risk factor for developing this chronic airflow impairment, but the early progression of disease is not well defined or understood. Ventilation/perfusion (V/Q) SPECT provides a noninvasive assessment of lung function to further our current understanding of how CS affects the lung. METHODS BALB/c mice were imaged with V/Q SPECT and CT after 8 and 24 wk of whole-body exposure to mainstream CS. Bronchoalveolar lavage was collected and cell differentials produced to determine inflammatory patterns. Histologic lung sections were collected, and a semiautomated quantitative analysis of airspace enlargement was applied to whole histology slices. RESULTS Exposure to CS induced an inflammatory response that included increases in the numbers of both mononuclear cells and neutrophils. Airspace enlargement was also significantly increased at 8 wk of CS exposure and was still more pronounced at 24 wk. Ventilation and perfusion correlation at the voxel level depicted a significant decrease in matching at 8 wk of CS exposure that was also apparent after 24 wk. The standard deviation (SD) of the log(V/Q) curve, a basic measure of heterogeneity, was increased from 0.44 ± 0.02 in age-matched controls to 0.62 ± 0.05 with CS exposure at 24 wk, indicating an increase in V/Q mismatching between 8 and 24 wk of CS exposure. CT, however, was not capable of discriminating control from CS-exposed animals at either time point, even with greater resolution and respiratory gating. CONCLUSION This study demonstrated that, before CT detection of structural changes, V/Q imaging detected changes in gas-exchange potential. This functional impairment corresponded to increased lung inflammation and increased airspace enlargement. In vivo V/Q imaging can detect early changes to the lung caused by CS exposure and thus provides a noninvasive method of longitudinally studying lung dysfunction in preclinical models. In the future, these measures could be applied clinically to study and diagnose the early stages of chronic obstructive pulmonary disease.
Collapse
Affiliation(s)
- Brian N Jobse
- Department of Medicine, Division of Respirology, McMaster University, Hamilton, Ontario, Canada
| | | | | | | | | | | |
Collapse
|