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Park J, Kim EK, Lee SH, Kim MA, Kim JH, Lee SM, Lee JS, Oh YM, Lee SD, Lee JH. Phenotyping COPD Patients with Emphysema Distribution Using Quantitative CT Measurement; More Severe Airway Involvement in Lower Dominant Emphysema. Int J Chron Obstruct Pulmon Dis 2022; 17:2013-2025. [PMID: 36072609 PMCID: PMC9441583 DOI: 10.2147/copd.s362906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 07/21/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Jisoo Park
- Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Eun-Kyung Kim
- Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Se Hee Lee
- Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Mi-Ae Kim
- Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Jung-Hyun Kim
- Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Sang Min Lee
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jae Seung Lee
- Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Yeon-Mok Oh
- Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang-Do Lee
- Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Ji-Hyun Lee
- Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
- Correspondence: Ji-Hyun Lee, Department of Pulmonology, Allergy and Critical Care Medicine, CHA Bundang Medical Center, CHA University, 59, Yatap-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea, Tel +82-31-780-5205, Fax +82-31-780-2992, Email
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Lor KL, Chang YC, Yu CJ, Wang CY, Chen CM. Bullous Parametric Response Map for Functional Localization of COPD. J Digit Imaging 2022; 35:115-126. [PMID: 35018538 PMCID: PMC8921375 DOI: 10.1007/s10278-021-00561-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/27/2021] [Accepted: 12/01/2021] [Indexed: 11/26/2022] Open
Abstract
Advanced bronchoscopic lung volume reduction treatment (BLVR) is now a routine care option for treating patients with severe emphysema. Patterns of low attenuation clusters indicating emphysema and functional small airway disease (fSAD) on paired CT, which may provide additional insights to the target selection of the segmental or subsegmental lobe of the treatments, require further investigation. The low attenuation clusters (LACS) were segmented to identify the scalar and spatial distribution of the lung destructions, in terms of 10 fractions scales of low attenuation density (LAD) located in upper lobes and lower lobes. The LACs of functional small airway disease (fSAD) were delineated by applying the technique of parametric response map (PRM) on the co-registered CT image data. Both emphysematous LACs of inspiratory CT and fSAD LACs on expiratory CT were used to derive the coefficients of the predictive model for estimating the airflow limitation. The voxel-wise severity is then predicted using the regional LACs on the co-registered CT to indicate the functional localization, namely, the bullous parametric response map (BPRM). A total of 100 subjects, 88 patients with mild to very severe COPD and 12 control participants with normal lung functions (FEV1/FVC % > 70%), were evaluated. Pearson’s correlations between FEV1/FVC% and LAV%HU-950 of severe emphysema are − 0.55 comparing to − 0.67 and − 0.62 of LAV%HU-856 of air-trapping and LAV%fSAD respectively. Pearson’s correlation between FEV1/FVC% and FEV1/FVC% predicted by the proposed model using LAD% of HU-950 and fSAD on BPRM is 0.82 (p < 0.01). The result of the Bullous Parametric Response Map (BPRM) is capable of identifying the less functional area of the lung, where the BLVR treatment is aimed at removing from a hyperinflated area of emphysematous regions.
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Affiliation(s)
- Kuo-Lung Lor
- Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Yeun-Chung Chang
- Department of Medical Imaging, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chong-Jen Yu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Cheng-Yi Wang
- Department of Internal Medicine, College of Medicine, Cardinal Tien Hospital and School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Chung-Ming Chen
- Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
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Abd elsalam SM, Hafez M, Mohmed MF, Said AH. Correlation between quantitative multi-detector computed tomography lung analysis and pulmonary function tests in chronic obstructive pulmonary disease patients. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2020. [DOI: 10.1186/s43055-020-00281-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Chronic obstructive pulmonary disease [COPD] is a very common disease in developing as well as in developed countries. Using CT has a growing interest to give a phenotypic classification helping the clinical characterization of COPD patients. So, the aim of the present study was to evaluate whether there was a significant correlation between quantitative computed tomography lung analysis and pulmonary function tests in chronic obstructive pulmonary disease patients.
Results
The study included 50 male patients with a mean age of 62.82 years ± 8.65 years standard deviation [SD]. Significant correlation was found between the pulmonary function tests [FEV1 and FEV1/FVC ratio], and all parameters of quantitative assessment with – 950 HU [the percentage of low-attenuation areas (% LAA)]. Pulmonary function tests according to GOLD [Global Initiative for Chronic Obstructive Lung Disease] guidelines revealed that 4% had normal pulmonary function, 8% had mild obstructive defect, 32% had moderate obstructive defect, 26% had severe obstructive defect, and 30% had very severe obstructive defect.
Conclusion
Automated CT densitometry defining the emphysema severity was significantly correlated with the parameters of pulmonary function tests and providing an alternative, quick, simple, non-invasive study for evaluation of emphysema severity. Its main importance was the determination of the extent and distribution of affected emphysematous parts of the lungs especially for selecting the patients suitable for the lung volume reduction surgery.
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Predictive Modelling of Lung Function using Emphysematous Density Distribution. Sci Rep 2019; 9:19763. [PMID: 31875053 PMCID: PMC6930211 DOI: 10.1038/s41598-019-56351-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 12/10/2019] [Indexed: 11/08/2022] Open
Abstract
Target lung tissue selection remains a challenging task to perform for treating severe emphysema with lung volume reduction (LVR). In order to target the treatment candidate, the percentage of low attenuation volume (LAV%) representing the proportion of emphysema volume to whole lung volume is measured using computed tomography (CT) images. Although LAV% have shown to have a correlation with lung function in patients with chronic obstructive pulmonary disease (COPD), similar measurements of LAV% in whole lung or lobes may have large variations in lung function due to emphysema heterogeneity. The functional information of regional emphysema destruction is required for supporting the choice of optimal target. The purpose of this study is to develop an emphysema heterogeneity descriptor for the three-dimensional emphysematous bullae according to the size variations of emphysematous density (ED) and their spatial distribution. The second purpose is to derive a predictive model of airflow limitation based on the regional emphysema heterogeneity. Deriving the bullous representation and grouping them into four scales in the upper and lower lobes, a predictive model is computed using the linear model fitting to estimate the severity of lung function. A total of 99 subjects, 87 patients with mild to very severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I~IV) and 12 control participants with normal lung functions (forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) > 0.7) were evaluated. The final model was trained with stratified cross-validation on randomly selected 75% of the dataset (n = 76) and tested on the remaining dataset (n = 23). The dispersed cases of LAV% inconsistent with their lung function outcome were evaluated, and the correlation study suggests that comparing to LAV of larger bullae, the widely spread smaller bullae with equivalent LAV has a larger impact on lung function. The testing dataset has the correlation of r = -0.76 (p < 0.01) between the whole lung LAV% and FEV1/FVC, whereas using two ED % of scales and location-dependent variables to predict the emphysema-associated FEV1/FVC, the results shows their correlation of 0.82 (p < 0.001) with clinical FEV1/FVC.
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Li K, Gao Y, Pan Z, Jia X, Yan Y, Min X, Huang K, Jiang T. Influence of Emphysema and Air Trapping Heterogeneity on Pulmonary Function in Patients with COPD. Int J Chron Obstruct Pulmon Dis 2019; 14:2863-2872. [PMID: 31839706 PMCID: PMC6905406 DOI: 10.2147/copd.s221684] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 11/23/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose To explore the influence of emphysema and air trapping heterogeneity on pulmonary function changes in patients with stable chronic obstructive pulmonary disease (COPD). Patients and methods One hundred and seventy-nine patients with stable COPD were enrolled in this prospective study. All patients underwent low-dose inspiratory and expiratory CT scanning and pulmonary-function tests. CT quantitative data for the emphysema index (EI) on full-inspiration and air trapping (AT) on full-expiration were measured for the whole lung, the right and left lungs, and the cranial-caudal lung zones. The heterogeneity index (HI) values for emphysema and air trapping were determined as the ratio of the difference to the sum of the respective indexes. The cranial-caudal HI and left–right lung HI were compared between mild-to-moderate (GOLD stage I and II) and severe (GOLD stage III and IV) disease groups. The associations between HI and pulmonary-function measurements adjusted for age, sex, height, smoking history, EI and AT of the total lung were assessed using multiple linear regression analysis. Results The absolute values for cranial-caudal HI (AT_CC_HI) and left–right lung HI (AT_LR_HI) on full-expiration were significantly larger in the mild-to-moderate group, while no significant intergroup differences were observed on full-inspiration. COPD patients with lower-zone and/or left-lung predominance showed significantly lower pulmonary function than those with upper-zone and/or right-lung predominance on full-expiration, whereas no significant differences were observed on full-inspiration. The absolute values of AT_CC_HI and AT_LR_HI significantly correlated with pulmonary-function measurements. Higher AT_CC_HI and lower AT_LR_HI absolute values indicated better pulmonary function, after adjusting for age, sex, height, smoking history, EI and AT of the total lung. Conclusion Subjects with more heterogeneous distribution and/or upper-zone predominant and/or right-lung predominant patterns on full-expiration tend to have better pulmonary function. Thus, in comparison with emphysema heterogeneity, AT heterogeneity better reflects the pulmonary function changes in COPD patients.
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Affiliation(s)
- Kun Li
- Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, Republic of China
| | - Yanli Gao
- Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, Republic of China
| | - Zhenyu Pan
- Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, Republic of China
| | - Xiuqin Jia
- Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, Republic of China
| | - Yuchang Yan
- Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, Republic of China
| | - Xiaohong Min
- Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, Republic of China
| | - Kewu Huang
- Department of Pulmonary and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing Institute of Respiratory Medicine, Beijing, People's Republic of China
| | - Tao Jiang
- Department of Radiology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, Republic of China
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Šileikienė V, Urbonas M, Matačiūnas M, Norkūnienė J. Relationships between pulmonary function test parameters and quantitative computed tomography measurements of emphysema in subjects with chronic obstructive pulmonary disease. Acta Med Litu 2018; 24:209-218. [PMID: 29487484 PMCID: PMC5818256 DOI: 10.6001/actamedica.v24i4.3616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Objective. CT is able to precisely define the pathological process in COPD. There are a number of previous articles discussing the distribution of emphysema and its connection with pulmonary function tests. However, the results obtained by the researchers are not identical. Purpose. To assess relationships between emphysema and pulmonary function test parameters in COPD patients. Materials and methods. Fifty-nine patients diagnosed to have COPD underwent chest CT examinations and pulmonary function tests. For the quantitative assessment, percentages of low attenuation volume LAV 950 HU (%) of a both lungs, the right lung, the left lung, and each lobe were obtained. Quantitative CT measurements were compared with forced expiratory volume in 1 s (FEV1), the ratio of FEV1 to forced vital capacity (FEV1/FVC), the diffusing capacity for carbon monoxide (DLco) and total lung capacity (TLC). Results. Except for the right middle lobe and the right upper lobe, respectively, all the quantitative CT measurements showed weak to moderate negative correlations with diffusing capacity (DLco) (r = –0.35 to –0.61, p < 0.05) and weak positive correlations with TLC (r = 0.34 to 0.44, p < 0.05). Group analysis indicated that LAV–950 HU (%) values of both lungs, right lung, left lung, and each lobe, except for right middle lobe, were increased in patients with GOLD stages 3 and 4 of COPD compared to GOLD stages 1 and 2 (p < 0.05). Conclusion. CT measurements of emphysema are significantly related to pulmonary function tests results, particularly DLco.
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Affiliation(s)
- Virginija Šileikienė
- Centre of Pulmonology and Allergology of Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania.,Clinic of Infectious and Chest Diseases, Dermatovenerology and Allergology of Vilnius University, Vilnius, Lithuania
| | - Marius Urbonas
- Centre of Radiology and Nuclear Medicine of Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania
| | - Mindaugas Matačiūnas
- Centre of Radiology and Nuclear Medicine of Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania
| | - Jolita Norkūnienė
- Department of Mathematical Statistics of Vilnius Gediminas Technical University, Vilnius, Lithuania
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Crossley D, Renton M, Khan M, Low EV, Turner AM. CT densitometry in emphysema: a systematic review of its clinical utility. Int J Chron Obstruct Pulmon Dis 2018; 13:547-563. [PMID: 29445272 PMCID: PMC5808715 DOI: 10.2147/copd.s143066] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The aim of the study was to assess the relationship between computed tomography (CT) densitometry and routine clinical markers in patients with chronic obstructive pulmonary disease (COPD) and alpha-1 anti-trypsin deficiency (AATD). METHODS Multiple databases were searched using a combination of pertinent terms and those articles relating quantitatively measured CT densitometry to clinical outcomes. Studies that used visual scoring only were excluded, as were those measured in expiration only. A thorough review of abstracts and full manuscripts was conducted by 2 reviewers; data extraction and assessment of bias was conducted by 1 reviewer and the 4 reviewers independently assessed for quality. Pooled correlation coefficients were calculated, and heterogeneity was explored. RESULTS A total of 112 studies were identified, 82 being suitable for meta-analysis. The most commonly used density threshold was -950 HU, and a significant association between CT density and all included clinical parameters was demonstrated. There was marked heterogeneity between studies secondary to large variety of disease severity within commonly included cohorts and differences in CT acquisition parameters. CONCLUSION CT density shows a good relationship to clinically relevant parameters; however, study heterogeneity and lack of longitudinal data mean that it is difficult to compare studies or derive a minimal clinically important difference. We recommend that international consensus is reached to standardize CT conduct and analysis in future COPD and AATD studies.
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Affiliation(s)
- Diana Crossley
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
- Correspondence: Diana Crossley, Institute of Inflammation and Ageing, Queen Elizabeth Hospital, Mindelsohn Way, Edgbaston, Birmingham, B15 2TH, UK, Tel +44 121 371 3885, Fax +44 121 371 3203, Email
| | - Mary Renton
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Muhammad Khan
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Emma V Low
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Alice M Turner
- Institute of Applied Health Sciences, University of Birmingham, Birmingham, UK
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Boueiz A, Chang Y, Cho MH, Washko GR, San José Estépar R, Bowler RP, Crapo JD, DeMeo DL, Dy JG, Silverman EK, Castaldi PJ. Lobar Emphysema Distribution Is Associated With 5-Year Radiological Disease Progression. Chest 2017; 153:65-76. [PMID: 28943279 DOI: 10.1016/j.chest.2017.09.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/13/2017] [Accepted: 09/06/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Emphysema has considerable variability in its regional distribution. Craniocaudal emphysema distribution is an important predictor of the response to lung volume reduction. However, there is little consensus regarding how to define upper lobe-predominant and lower lobe-predominant emphysema subtypes. Consequently, the clinical and genetic associations with these subtypes are poorly characterized. METHODS We sought to identify subgroups characterized by upper-lobe or lower-lobe emphysema predominance and comparable amounts of total emphysema by analyzing data from 9,210 smokers without alpha-1-antitrypsin deficiency in the Genetic Epidemiology of COPD (COPDGene) cohort. CT densitometric emphysema was measured in each lung lobe. Random forest clustering was applied to lobar emphysema variables after regressing out the effects of total emphysema. Clusters were tested for association with clinical and imaging outcomes at baseline and at 5-year follow-up. Their associations with genetic variants were also compared. RESULTS Three clusters were identified: minimal emphysema (n = 1,312), upper lobe-predominant emphysema (n = 905), and lower lobe-predominant emphysema (n = 796). Despite a similar amount of total emphysema, the lower-lobe group had more severe airflow obstruction at baseline and higher rates of metabolic syndrome compared with subjects with upper-lobe predominance. The group with upper-lobe predominance had greater 5-year progression of emphysema, gas trapping, and dyspnea. Differential associations with known COPD genetic risk variants were noted. CONCLUSIONS Subgroups of smokers defined by upper-lobe or lower-lobe emphysema predominance exhibit different functional and radiological disease progression rates, and the upper-lobe predominant subtype shows evidence of association with known COPD genetic risk variants. These subgroups may be useful in the development of personalized treatments for COPD.
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Affiliation(s)
- Adel Boueiz
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Yale Chang
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA
| | - Michael H Cho
- Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - George R Washko
- Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Raul San José Estépar
- Surgical Planning Laboratory, Laboratory of Mathematics in Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Russell P Bowler
- Division of Pulmonary Medicine, Department of Medicine, National Jewish Health, Denver, CO
| | - James D Crapo
- Division of Pulmonary Medicine, Department of Medicine, National Jewish Health, Denver, CO
| | - Dawn L DeMeo
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Jennifer G Dy
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA
| | - Edwin K Silverman
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Peter J Castaldi
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of General Medicine and Primary Care, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
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Boueiz A, Lutz SM, Cho MH, Hersh CP, Bowler RP, Washko GR, Halper-Stromberg E, Bakke P, Gulsvik A, Laird NM, Beaty TH, Coxson HO, Crapo JD, Silverman EK, Castaldi PJ, DeMeo DL. Genome-Wide Association Study of the Genetic Determinants of Emphysema Distribution. Am J Respir Crit Care Med 2017; 195:757-771. [PMID: 27669027 DOI: 10.1164/rccm.201605-0997oc] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
RATIONALE Emphysema has considerable variability in the severity and distribution of parenchymal destruction throughout the lungs. Upper lobe-predominant emphysema has emerged as an important predictor of response to lung volume reduction surgery. Yet, aside from alpha-1 antitrypsin deficiency, the genetic determinants of emphysema distribution remain largely unknown. OBJECTIVES To identify the genetic influences of emphysema distribution in non-alpha-1 antitrypsin-deficient smokers. METHODS A total of 11,532 subjects with complete genotype and computed tomography densitometry data in the COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease [COPD]; non-Hispanic white and African American), ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints), and GenKOLS (Genetics of Chronic Obstructive Lung Disease) studies were analyzed. Two computed tomography scan emphysema distribution measures (difference between upper-third and lower-third emphysema; ratio of upper-third to lower-third emphysema) were tested for genetic associations in all study subjects. Separate analyses in each study population were followed by a fixed effect metaanalysis. Single-nucleotide polymorphism-, gene-, and pathway-based approaches were used. In silico functional evaluation was also performed. MEASUREMENTS AND MAIN RESULTS We identified five loci associated with emphysema distribution at genome-wide significance. These loci included two previously reported associations with COPD susceptibility (4q31 near HHIP and 15q25 near CHRNA5) and three new associations near SOWAHB, TRAPPC9, and KIAA1462. Gene set analysis and in silico functional evaluation revealed pathways and cell types that may potentially contribute to the pathogenesis of emphysema distribution. CONCLUSIONS This multicohort genome-wide association study identified new genomic loci associated with differential emphysematous destruction throughout the lungs. These findings may point to new biologic pathways on which to expand diagnostic and therapeutic approaches in chronic obstructive pulmonary disease. Clinical trial registered with www.clinicaltrials.gov (NCT 00608764).
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Affiliation(s)
- Adel Boueiz
- 1 Channing Division of Network Medicine.,2 Pulmonary and Critical Care Division, Department of Medicine, and
| | - Sharon M Lutz
- 3 Department of Biostatistics, Colorado School of Public Health, University of Colorado, Aurora, Colorado
| | - Michael H Cho
- 1 Channing Division of Network Medicine.,2 Pulmonary and Critical Care Division, Department of Medicine, and
| | - Craig P Hersh
- 1 Channing Division of Network Medicine.,2 Pulmonary and Critical Care Division, Department of Medicine, and
| | - Russell P Bowler
- 4 Division of Pulmonary Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - George R Washko
- 2 Pulmonary and Critical Care Division, Department of Medicine, and
| | - Eitan Halper-Stromberg
- 4 Division of Pulmonary Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Per Bakke
- 5 Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Amund Gulsvik
- 5 Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Nan M Laird
- 6 Harvard School of Public Health, Boston, Massachusetts
| | - Terri H Beaty
- 7 Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland; and
| | - Harvey O Coxson
- 8 Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - James D Crapo
- 4 Division of Pulmonary Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Edwin K Silverman
- 1 Channing Division of Network Medicine.,2 Pulmonary and Critical Care Division, Department of Medicine, and
| | - Peter J Castaldi
- 1 Channing Division of Network Medicine.,9 Division of General Medicine and Primary Care, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Dawn L DeMeo
- 1 Channing Division of Network Medicine.,2 Pulmonary and Critical Care Division, Department of Medicine, and
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Bhatt SP, Bodduluri S, Newell JD, Hoffman EA, Sieren JC, Han MK, Dransfield MT, Reinhardt JM. CT-derived Biomechanical Metrics Improve Agreement Between Spirometry and Emphysema. Acad Radiol 2016; 23:1255-63. [PMID: 27055745 DOI: 10.1016/j.acra.2016.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/04/2016] [Accepted: 02/06/2016] [Indexed: 10/22/2022]
Abstract
RATIONALE AND OBJECTIVES Many patients with chronic obstructive pulmonary disease (COPD) have marked discordance between forced expiratory volume in 1 second (FEV1) and degree of emphysema on computed tomography (CT). Biomechanical differences between these patients have not been studied. We aimed to identify reasons for the discordance between CT and spirometry in some patients with COPD. MATERIALS AND METHODS Subjects with Global initiative for chronic Obstructive Lung Disease stages I-IV from a large multicenter study (The Genetic Epidemiology of COPD) were arranged by percentiles of %predicted FEV1 and emphysema on CT. Three categories were created using differences in percentiles: Catspir with predominant airflow obstruction/minimal emphysema, CatCT with predominant emphysema/minimal airflow obstruction, and Catmatched with matched FEV1 and emphysema. Image registration was used to derive Jacobian determinants, a measure of lung elasticity, anisotropy, and strain tensors, to assess biomechanical differences between groups. Regression models were created with the previously mentioned categories as outcome variable, adjusting for demographics, scanner type, quantitative CT-derived emphysema, gas trapping, and airway thickness (model 1), and after adding biomechanical CT metrics (model 2). RESULTS Jacobian determinants, anisotropy, and strain tensors were strongly associated with FEV1. With Catmatched as control, model 2 predicted Catspir and CatCT better than model 1 (Akaike information criterion 255.8 vs. 320.8). In addition to demographics, the strongest independent predictors of FEV1 were Jacobian mean (β = 1.60,95%confidence intervals [CI] = 1.16 to 1.98; P < 0.001), coefficient of variation (CV) of Jacobian (β = 1.45,95%CI = 0.86 to 2.03; P < 0.001), and CV of strain (β = 1.82,95%CI = 0.68 to 2.95; P = 0.001). CVs of Jacobian and strain are both potential markers of biomechanical lung heterogeneity. CONCLUSIONS CT-derived measures of lung mechanics improve the link between quantitative CT and spirometry, offering the potential for new insights into the linkage between regional parenchymal destruction and global decrement in lung function in patients with COPD.
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Bastos HNE, Neves I, Redondo M, Cunha R, Pereira JM, Magalhães A, Fernandes G. Influence of emphysema distribution on pulmonary function parameters in COPD patients. J Bras Pneumol 2016; 41:489-95. [PMID: 26785956 PMCID: PMC4722999 DOI: 10.1590/s1806-37562015000000136] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 11/04/2015] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE: To evaluate the impact that the distribution of emphysema has on clinical and functional severity in patients with COPD. METHODS: The distribution of the emphysema was analyzed in COPD patients, who were classified according to a 5-point visual classification system of lung CT findings. We assessed the influence of emphysema distribution type on the clinical and functional presentation of COPD. We also evaluated hypoxemia after the six-minute walk test (6MWT) and determined the six-minute walk distance (6MWD). RESULTS: Eighty-six patients were included. The mean age was 65.2 ± 12.2 years, 91.9% were male, and all but one were smokers (mean smoking history, 62.7 ± 38.4 pack-years). The emphysema distribution was categorized as obviously upper lung-predominant (type 1), in 36.0% of the patients; slightly upper lung-predominant (type 2), in 25.6%; homogeneous between the upper and lower lung (type 3), in 16.3%; and slightly lower lung-predominant (type 4), in 22.1%. Type 2 emphysema distribution was associated with lower FEV1, FVC, FEV1/FVC ratio, and DLCO. In comparison with the type 1 patients, the type 4 patients were more likely to have an FEV1 < 65% of the predicted value (OR = 6.91, 95% CI: 1.43-33.45; p = 0.016), a 6MWD < 350 m (OR = 6.36, 95% CI: 1.26-32.18; p = 0.025), and post-6MWT hypoxemia (OR = 32.66, 95% CI: 3.26-326.84; p = 0.003). The type 3 patients had a higher RV/TLC ratio, although the difference was not significant. CONCLUSIONS: The severity of COPD appears to be greater in type 4 patients, and type 3 patients tend to have greater hyperinflation. The distribution of emphysema could have a major impact on functional parameters and should be considered in the evaluation of COPD patients.
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Affiliation(s)
| | - Inês Neves
- Centro Hospitalar de São João EPE, Porto, Portugal
| | | | - Rui Cunha
- Serviço de Radiologia, Centro Hospitalar de São João EPE, Porto, Portugal
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12
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Quantitative emphysema assessment of pulmonary function impairment by computed tomography in chronic obstructive pulmonary disease. J Comput Assist Tomogr 2015; 39:171-5. [PMID: 25474145 DOI: 10.1097/rct.0000000000000187] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The objective of this study was to determine the capability of quantitative emphysema by computed tomography (CT) to assess pulmonary function impairment in a population of current smokers with and without airflow limitation. METHODS Seventy-six subjects (30 normal smokers; 8 with mild obstruction; 17 with moderate obstruction; 13 with severe obstruction; 8 with very severe obstruction) underwent CT examinations and pulmonary function tests. For the quantitative assessment, percentages of low attenuation volume (%LAVs) of whole lung, right lung, left lung, and each lobe were obtained. Computed tomography measurements were related to lung function (forced expiratory volume in 1 second [FEV1], ratio of FEV1 to forced vital capacity, diffusing capacity for carbon monoxide [DLCO], ratio of residual volume to total lung capacity [RV/TLC]) by multivariate linear regression analysis. RESULTS Quantitative CT measurements of emphysema were moderately, negatively correlated to airflow limitation (FEV1 and ratio of FEV1 to forced vital capacity) (r = -0.68 to -0.52, P < 0.001). Except for right middle and lower lobes, all the quantitative CT measurements showed moderate, negative correlations with diffusing capacity (DLCO) (r = -0.63 to -0.54, P ≤ 0.001) and weak to moderate correlations with RV (RV/TLC) (r = 0.36-0.41, P < 0.01). As compared with control samples, the %LAV of whole lung, right lung, left lung, and each lobe was increased in patients with GOLD stages 2, 3, and 4 disease (P < 0.05), and the % LAV of whole lung, right lung and right upper lobe was increased in patients with GOLD stage 1 (P < 0.05). CONCLUSIONS Pulmonary function results, particularly DLCO and RV/TLC, were primarily affected by the % LAV of the upper lobes. Quantitative CT measurements of emphysema provides a morphological method to investigate lung function impairment in patients with chronic obstructive pulmonary disease.
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Kitano M, Iwano S, Hashimoto N, Matsuo K, Hasegawa Y, Naganawa S. Lobar analysis of collapsibility indices to assess functional lung volumes in COPD patients. Int J Chron Obstruct Pulmon Dis 2014; 9:1347-56. [PMID: 25525352 PMCID: PMC4266257 DOI: 10.2147/copd.s72616] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background We investigated correlations between lung volume collapsibility indices and pulmonary function test (PFT) results and assessed lobar differences in chronic obstructive pulmonary disease (COPD) patients, using paired inspiratory and expiratory three dimensional (3D) computed tomography (CT) images. Methods We retrospectively assessed 28 COPD patients who underwent paired inspiratory and expiratory CT and PFT exams on the same day. A computer-aided diagnostic system calculated total lobar volume and emphysematous lobar volume (ELV). Normal lobar volume (NLV) was determined by subtracting ELV from total lobar volume, both for inspiratory phase (NLVI) and for expiratory phase (NLVE). We also determined lobar collapsibility indices: NLV collapsibility ratio (NLVCR) (%) = (1 − NLVE/NLVI) × 100%. Associations between lobar volumes and PFT results, and collapsibility indices and PFT results were determined by Pearson correlation analysis. Results NLVCR values were significantly correlated with PFT results. Forced expiratory volume in 1 second, measured as percent of predicted results (FEV1%P) was significantly correlated with NLVCR values for the lower lobes (P<0.01), whereas this correlation was not significant for the upper lobes (P=0.05). FEV1%P results were also moderately correlated with inspiratory, expiratory ELV (ELVI,E) for the lower lobes (P<0.05). In contrast, the ratio of the diffusion capacity for carbon monoxide to alveolar gas volume, measured as percent of predicted (DLCO/VA%P) results were strongly correlated with ELVI for the upper lobes (P<0.001), whereas this correlation with NLVCR values was weaker for upper lobes (P<0.01) and was not significant for the lower lobes (P=0.26). Conclusion FEV1%P results were correlated with NLV collapsibility indices for lower lobes, whereas DLCO/VA%P results were correlated with NLV collapsibility indices and ELV for upper lobes. Thus, evaluating lobar NLV collapsibility might be useful for estimating pulmonary function in COPD patients.
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Affiliation(s)
- Mariko Kitano
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Shingo Iwano
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Naozumi Hashimoto
- Department of Respiratory Medicine, Graduate School of Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Keiji Matsuo
- Department of Radiology, Ichinomiya Municipal Hospital, Ichinomiya, Aichi, Japan
| | - Yoshinori Hasegawa
- Department of Respiratory Medicine, Graduate School of Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
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Boutou AK, Nair A, Douraghi-Zadeh D, Sandhu R, Hansell DM, Wells AU, Polkey MI, Hopkinson NS. A combined pulmonary function and emphysema score prognostic index for staging in Chronic Obstructive Pulmonary Disease. PLoS One 2014; 9:e111109. [PMID: 25343258 PMCID: PMC4208797 DOI: 10.1371/journal.pone.0111109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 09/29/2014] [Indexed: 11/18/2022] Open
Abstract
Introduction Chronic Obstructive Pulmonary Disease (COPD) is characterized by high morbidity and mortality. Lung computed tomography parameters, individually or as part of a composite index, may provide more prognostic information than pulmonary function tests alone. Aim To investigate the prognostic value of emphysema score and pulmonary artery measurements compared with lung function parameters in COPD and construct a prognostic index using a contingent staging approach. Material-Methods Predictors of mortality were assessed in COPD outpatients whose lung computed tomography, spirometry, lung volumes and gas transfer data were collected prospectively in a clinical database. Univariate and multivariate Cox proportional hazard analysis models with bootstrap techniques were used. Results 169 patients were included (59.8% male, 61.1 years old; Forced Expiratory Volume in 1 second % predicted: 40.5±19.2). 20.1% died; mean survival was 115.4 months. Age (HR = 1.098, 95% Cl = 1.04–1.252) and emphysema score (HR = 1.034, 95% CI = 1.007–1.07) were the only independent predictors of mortality. Pulmonary artery dimensions were not associated with survival. An emphysema score of 55% was chosen as the optimal threshold and 30% and 65% as suboptimals. Where emphysema score was between 30% and 65% (intermediate risk) the optimal lung volume threshold, a functional residual capacity of 210% predicted, was applied. This contingent staging approach separated patients with an intermediate risk based on emphysema score alone into high risk (Functional Residual Capacity ≥210% predicted) or low risk (Functional Residual Capacity <210% predicted). This approach was more discriminatory for survival (HR = 3.123; 95% CI = 1.094–10.412) than either individual component alone. Conclusion Although to an extent limited by the small sample size, this preliminary study indicates that the composite Emphysema score-Functional Residual Capacity index might provide a better separation of high and low risk patients with COPD, than other individual predictors alone.
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Affiliation(s)
- Afroditi K. Boutou
- NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, United Kingdom
| | - Arjun Nair
- NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, United Kingdom
| | - Dariush Douraghi-Zadeh
- Department of Radiology, Chelsea and Westminster NHS Foundation Trust, London, United Kingdom
| | - Ranbir Sandhu
- Department of Radiology, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - David M. Hansell
- NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, United Kingdom
| | - Athol U. Wells
- NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, United Kingdom
| | - Michael I. Polkey
- NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, United Kingdom
| | - Nicholas S. Hopkinson
- NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, United Kingdom
- * E-mail:
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Owsijewitsch M, Ley-Zaporozhan J, Kuhnigk JM, Kopp-Schneider A, Eberhardt R, Eichinger M, Heussel CP, Kauczor HU, Ley S. Quantitative Emphysema Distribution in Anatomic and Non-anatomic Lung Regions. COPD 2014; 12:257-66. [PMID: 25230093 DOI: 10.3109/15412555.2014.933950] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE The change of emphysema distribution with increasing COPD severity is not yet assessed. Especially, involvement of the upper aspect of the lower lobe is unknown. The primary aim was to quantitatively determine regional distribution of emphysema in anatomically (lung lobes) and non-anatomically defined lung regions (upper/lower lung halves as well as core and rind regions) in a cohort covering equally all COPD severity stages using CT. MATERIAL AND METHODS Basically 100 CT data sets were quantitatively evaluated for regional distribution of emphysema. Emphysema characteristics (emphysema index, mean lung density and 15th percentile of the attenuation values of lung voxels) were compared (t-test) in: upper lobes vs. upper halves, lower lobes vs. lower halves, core vs. rind region. RESULTS In patients with ≤ GOLD II, a significantly higher emphysema burden was found in the upper lobes as compared to upper halves. In subjects with GOLD III/IV the differences were not significant for all emphysema characteristics. A high difference between lobes and halves in subjects with ≤ GOLD II was found, in contrast to low difference in higher GOLD stages. CONCLUSIONS Lobar segmentation provides improved characterization of cranio-caudal emphysema distribution compared to a non-anatomic approach in subjects up to GOLD stage II.
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Affiliation(s)
- Michael Owsijewitsch
- 1Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg , Heidelberg , Germany
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16
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Bhatt SP, Sieren JC, Newell JD, Comellas AP, Hoffman EA. Disproportionate contribution of right middle lobe to emphysema and gas trapping on computed tomography. PLoS One 2014; 9:e102807. [PMID: 25054539 PMCID: PMC4108372 DOI: 10.1371/journal.pone.0102807] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 06/24/2014] [Indexed: 11/18/2022] Open
Abstract
RATIONALE Given that the diagnosis of chronic obstructive pulmonary disease (COPD) relies on demonstrating airflow limitation by spirometry, which is known to be poorly sensitive to early disease, and to regional differences in emphysema, we sought to evaluate individual lobar contributions to global spirometric measures. METHODS Subjects with COPD were compared with smokers without airflow obstruction, and non-smokers. Emphysema (% low attenuation area, LAAinsp<-950 HU, at end-inspiration) and gas trapping (%LAAexp<-856 HU at end-expiration) on CT were quantified using density mask analyses for the whole lung and for individual lobes, and distribution across lobes and strength of correlation with spirometry were compared. RESULTS The right middle lobe had the highest %LAAinsp<-950 HU in smokers and controls, and the highest %LAAexp<-856 HU in all three groups. While RML contributed to emphysema and gas trapping disproportionately to its relatively small size, it also showed the least correlation with spirometry. There was no change in correlation of whole lung CT metrics with spirometry when the middle lobe was excluded from analyses. Similarly, RML had the highest %LAAexp<-856 HU while having the least correlation with spirometry. CONCLUSIONS Because of the right middle lobe's disproportionate contribution to CT-based emphysema measurements, and low contribution to spirometry, longitudinal studies of emphysema progression may benefit from independent analysis of the middle lobe in whole lung quantitative CT assessments. Our findings may also have implications for heterogeneity assessments and target lobe selection for lung volume reduction. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov NCT00608764.
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Affiliation(s)
- Surya P. Bhatt
- Division of Pulmonary and Critical Care Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jessica C. Sieren
- Departments of Radiology and Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States of America
| | - John D. Newell
- Departments of Radiology and Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States of America
| | - Alejandro P. Comellas
- Division of Pulmonary and Critical Care Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Eric A. Hoffman
- Departments of Radiology and Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States of America
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Multidetector Computed Tomographic Imaging in Chronic Obstructive Pulmonary Disease. Radiol Clin North Am 2014; 52:137-54. [DOI: 10.1016/j.rcl.2013.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Harvey BG, Strulovici-Barel Y, Vincent TL, Mezey JG, Raviram R, Gordon C, Salit J, Tilley AE, Chung A, Sanders A, Crystal RG. High correlation of the response of upper and lower lobe small airway epithelium to smoking. PLoS One 2013; 8:e72669. [PMID: 24039793 PMCID: PMC3767732 DOI: 10.1371/journal.pone.0072669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 07/18/2013] [Indexed: 01/15/2023] Open
Abstract
The distribution of lung disease induced by inhaled cigarette smoke is complex, depending on many factors. With the knowledge that the small airway epithelium (SAE) is the earliest site of smoking-induced lung disease, and that the SAE gene expression is likely sensitive to inhaled cigarette smoke, we compared upper vs. lower lobe gene expression in the SAE within the same cigarette smokers to determine if the gene expression patterns were similar or different. Active smokers (n = 11) with early evidence of smoking-induced lung disease (normal spirometry but low diffusing capacity) underwent bronchoscopy and brushing of the upper and lower lobe SAE in order to compare upper vs lower lobe genome-wide and smoking-responsive gene expression by microarray. Cluster and principal component analysis demonstrated that, for each individual, the expression of the known SAE smoking-responsive genes were highly correlated in upper and lower lobe pairs, although, as expected, there were differences in the smoking-induced changes in gene expression from individual to individual. These observations support the concept that the heterogeneity observed among smokers in the anatomic distribution of smoking-induced disease are not secondary to the topographic differences in the effects of cigarette smoke on the airway epithelium.
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Affiliation(s)
- Ben-Gary Harvey
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, New York, United States of America
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Yael Strulovici-Barel
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Thomas L. Vincent
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Jason G. Mezey
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, New York, United States of America
| | - Ramya Raviram
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Cynthia Gordon
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Jacqueline Salit
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Ann E. Tilley
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, New York, United States of America
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Augustine Chung
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Abraham Sanders
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Ronald G. Crystal
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, New York, United States of America
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
- * E-mail:
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Takahashi M, Yamada G, Koba H, Takahashi H. Computed tomography-based centrilobular emphysema subtypes relate with pulmonary function. Open Respir Med J 2013; 7:54-9. [PMID: 23935765 PMCID: PMC3735927 DOI: 10.2174/1874306401307010054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/29/2013] [Accepted: 05/29/2013] [Indexed: 01/23/2023] Open
Abstract
Introduction: Centrilobular emphysema (CLE) is recognized as low attenuation areas (LAA) with centrilobular pattern on high-resolution computed tomography (CT). However, several shapes of LAA are observed. Our preliminary study showed three types of LAA in CLE by CT-pathologic correlations. This study was performed to investigate whether the morphological features of LAA affect pulmonary functions. Materials and Methods: A total of 73 Japanese patients with stable CLE (63 males, 10 females) were evaluated visually by CT and classified into three subtypes based on the morphology of LAA including shape and sharpness of border; patients with CLE who shows round or oval LAA with well-defined border (Subtype A), polygonal or irregular-shaped LAA with ill-defined border (Subtype B), and irregular-shaped LAA with ill-defined border coalesced with each other (Subtype C). CT score, pulmonary function test and smoking index were compared among three subtypes. Results: Twenty (27%), 45 (62%) and 8 cases (11%) of the patients were grouped into Subtype A, Subtype B and Subtype C, respectively. In CT score and smoking index, both Subtype B and Subtype C were significantly higher than Subtype A. In FEV1%, Subtype C was significantly lower than both Subtype A and Subtype B. In diffusing capacity of lung for carbon monoxide, Subtype B was significantly lower than Subtype A. Conclusion: The morphological differences of LAA may relate with an airflow limitation and alveolar diffusing capacity. To assess morphological features of LAA may be helpful for the expectation of respiratory function.
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Affiliation(s)
- Mamoru Takahashi
- Department of Respiratory Medicine and Allergology, Sapporo Medical University, School of Medicine, South-1 West-16, Chuo-ku, Sapporo 060-8543, Japan ; Department of Respirology, NTT East Corporation Sapporo Hospital, South-1 West-15, Chuo-ku, Sapporo 060-0061, Japan
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Wang Z, Gu S, Leader JK, Kundu S, Tedrow JR, Sciurba FC, Gur D, Siegfried JM, Pu J. Optimal threshold in CT quantification of emphysema. Eur Radiol 2012; 23:975-84. [PMID: 23111815 DOI: 10.1007/s00330-012-2683-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 08/24/2012] [Accepted: 08/30/2012] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine the optimal threshold by quantitatively assessing the extent of emphysema at the level of the entire lung and at the level of individual lobes using a large, diverse dataset of computed tomography (CT) examinations. METHODS This study comprises 573 chest CT examinations acquired from subjects with different levels of airway obstruction (222 none, 83 mild, 141 moderate, 63 severe and 64 very severe). The extent of emphysema was quantified using the percentage of the low attenuation area (LAA%) divided by the total lung or lobe volume(s). The correlations between the extent of emphysema, and pulmonary functions and the five-category classification were assessed using Pearson and Spearman's correlation coefficients, respectively. When quantifying emphysema using a density mask, a wide range of thresholds from -850 to -1,000 HU were used. RESULTS The highest correlations of LAA% with the five-category classification and PFT measures ranged from -925 to -965 HU for each individual lobe and the entire lung. However, the differences between the highest correlations and those obtained at -950 HU are relatively small. CONCLUSION Although there are variations in the optimal cut-off thresholds for individual lobes, the single threshold of -950 HU is still an acceptable threshold for density-based emphysema quantification.
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Affiliation(s)
- Zhimin Wang
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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Choromańska A, Macura KJ. Role of computed tomography in quantitative assessment of emphysema. Pol J Radiol 2012; 77:28-36. [PMID: 22802863 PMCID: PMC3389962 DOI: 10.12659/pjr.882578] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 01/19/2012] [Indexed: 11/09/2022] Open
Abstract
Pulmonary emphysema, together with chronic bronchitis is a part of chronic obstructive pulmonary disease (COPD), which is one of the leading causes of death in the United States and worldwide. There are many methods to diagnose emphysema. Unfortunately many of them, for example pulmonary function tests (PFTs), clinical signs and conventional radiology are able to detect emphysema usually in its late stages when a great portion of lung parenchyma has been already destroyed by the disease. Computed tomography (CT) allows for early detection of emphysema. CT also makes it possible to quantify the total amount of emphysema in the lungs which is important in order to precisely estimate the severity of the disease. Those abilities of CT are important in monitoring the course of the disease and in attempts to prevent its further progression. In this review we discuss currently available methods for imaging emphysema with emphasis on the quantitative assessment of emphysema. To date, quantitative methods have not been widely used clinically, however, the initial results of several research studies regarding this subject are very encouraging.
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3D-CT lung volumetry using multidetector row computed tomography: pulmonary function of each anatomic lobe. J Thorac Imaging 2012; 27:164-70. [PMID: 21873909 DOI: 10.1097/rti.0b013e31822641c9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE We sought to determine the volume of each anatomic lung lobe reconstructed using 3-dimensional computed tomography (3D-CT) imaging from multidetector CT images and to compare these with pulmonary function test results. MATERIALS AND METHODS We reviewed preoperative 3D-CT images and spirometry results of 111 patients (86 men and 25 women) with pulmonary neoplasms who were considered candidates for lung resections. On a 3D-CT image, the entire lung was semiautomatically separated into 5 anatomic lobes: right upper lobe, right middle lobe, right lower lobe, left upper lobe, and left lower lobe. For each lobe, total lobar volume, emphysematous lobar volume with low attenuation values of less than -950 HU, and normal lobar volume (NLV=total lobar volume-emphysematous lobar volume) were calculated. Vital capacity, forced expiratory volume in 1 second, and diffusing capacity for carbon monoxide (DLCO) were measured by spirometry. Relationships between NLV values of each lobe and pulmonary function results were determined by the Pearson correlation coefficients and multiple regression analysis. RESULTS The NLV values for both lower lobes (right lower lobe and left lower lobe) and the other lobes (right upper lobe, right middle lobe, and left upper lobe) were significantly correlated with vital capacity and forced expiratory volume in 1 second; lower lobes showed a stronger tendency toward these correlations. The NLV values of the lower lobes were significantly correlated with DLCO (P<0.001), although the NLV values of the other lobes were not correlated with DLCO (P=0.112). CONCLUSIONS Pulmonary function results, particularly DLCO, were primarily affected by the NLVs of the lower lobes.
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Iwasawa T, Takahashi H, Ogura T, Asakura A, Gotoh T, Shibata H, Inoue T. Influence of the distribution of emphysema on diaphragmatic motion in patients with chronic obstructive pulmonary disease. Jpn J Radiol 2011; 29:256-64. [PMID: 21607839 DOI: 10.1007/s11604-010-0552-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 12/13/2010] [Indexed: 11/30/2022]
Abstract
PURPOSE We investigated whether the distribution of emphysema on computed tomography (CT) images can affect chest wall motion in patients with chronic obstructive lung disease (COPD). MATERIALS AND METHODS The subjects were 35 male patients with COPD (age, 69.7 ± 6.2 years). The RA-950 (the ratio of lung volume under -950 HU to total lung volume on CT) was measured separately for the upper and lower halves of the lung. We analyzed the flatness of the diaphragm (Kdome) and its motion (ΔLappo) using dynamic magnetic resonance imaging. Paradoxical motion (Mpr) represented the ratio of the paradoxical diaphragmatic movement (downward or upward) when the lung area decreased or increased, respectively, to he total diaphragm movement (expressed as a percent). These parameters were analyzed in correlation with pulmonary function tests and St. George Respiratory Questionnaire (SGRQ) scores. RESULTS The RA-950 of the lower lung zone correlated significantly with the Kdome (P = 0.033), ΔLappo (P = 0.006), Mpr (%) (P = 0.001), forced expiratory volume at 1 s (% predicted; P < 0.001), and activity score of the SGRQ (p = 0.017). The RA-950 of the upper lung zone did not correlate with these parameters. CONCLUSION In COPD patients, the distribution of emphysema on CT correlates with airflow obstruction and abnormal diaphragmatic motion.
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Affiliation(s)
- Tae Iwasawa
- Department of Radiology, Kanagawa Cardiovascular and Respiratory Center, 6-16-1 Tomioka-Higashi, Kanazawa-ku, Yokohama 236-8651, Japan.
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Slope of emphysema index: an objective descriptor of regional heterogeneity of emphysema and an independent determinant of pulmonary function. AJR Am J Roentgenol 2010; 194:W248-55. [PMID: 20173123 DOI: 10.2214/ajr.09.2672] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to compare quantitative and visual assessments of regional heterogeneity of emphysema and to investigate the influence of regional heterogeneity on pulmonary function in smoking-related emphysema. MATERIALS AND METHODS We developed an automatic computerized algorithm to quantitatively assess heterogeneity in the upper-lower, anterior-posterior, and central-peripheral directions. The emphysema index was plotted with a linear function (emphysema index slopes: slope of emphysema index in upper-lower direction, slope of emphysema index in anterior-posterior direction, and slope of emphysema index in central-peripheral direction) for consecutive 1-pixel-thick slices using volumetric CT data of 59 patients (58 men and one woman; mean age, 65.7 years). Emphysema index was defined as the percentage area of lung with attenuation values below -950 HU. Visual assessment was performed using a 5-point scoring system. Quantitative and visual assessments were compared. Multiple linear regression was performed to evaluate the influence of emphysema index and emphysema index slopes on the pulmonary function test. RESULTS Quantitative and visual assessments were significantly correlated in both upper-lower (r(2) = 0.40 and r(2) = 0.67 for observers 1 and 2, respectively) and central-peripheral (r(2) = 0.51 and r(2) = 0.47, respectively) directions. Multiple linear regression revealed that emphysema index, slope of emphysema index in upper-lower direction, and slope of emphysema index in anterior-posterior direction were independent determinants of forced expiratory volume in 1 second (FEV(1)) (r(2) = 0.30; p < 0.001). Emphysema index and slope of emphysema index in upper-lower direction were independent determinants of the ratio of FEV(1) to forced vital capacity (FEV(1)/FVC) (r(2) = 0.32; p < 0.001). In addition to higher emphysema index, lower and posterior lung dominance was associated with a decrease in FEV(1) and FEV(1)/FVC. CONCLUSION Computerized, quantitative assessment using the emphysema index slope is comparable to visual assessment in the evaluation of regional heterogeneity of emphysema. In addition to the emphysema index, regional heterogeneity of smoking-related emphysema contributes to impairment of pulmonary function.
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Distribution of emphysema in heavy smokers: Impact on pulmonary function. Respir Med 2010; 104:76-82. [DOI: 10.1016/j.rmed.2009.08.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 07/27/2009] [Accepted: 08/05/2009] [Indexed: 11/22/2022]
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Matsuoka S, Yamashiro T, Washko GR, Kurihara Y, Nakajima Y, Hatabu H. Quantitative CT Assessment of Chronic Obstructive Pulmonary Disease. Radiographics 2010; 30:55-66. [DOI: 10.1148/rg.301095110] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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CT of pulmonary emphysema - current status, challenges, and future directions. Eur Radiol 2008; 19:537-51. [DOI: 10.1007/s00330-008-1186-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2008] [Revised: 07/16/2008] [Accepted: 08/15/2008] [Indexed: 10/21/2022]
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Hersh CP, Washko GR, Jacobson FL, Gill R, Estepar RSJ, Reilly JJ, Silverman EK. Interobserver Variability in the Determination of Upper Lobe-Predominant Emphysema. Chest 2007; 131:424-31. [PMID: 17296643 DOI: 10.1378/chest.06-1040] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Appropriateness for lung volume reduction surgery is often determined based on the results of high-resolution CT (HRCT) scanning of the chest. At many centers, radiologists and pulmonary physicians both review the images, but the agreement between readers from these specialties is not known. METHODS Two thoracic radiologists and three pulmonologists retrospectively reviewed the HRCT scans of 30 patients with emphysema involved in two clinical studies at our institution. Each reader assigned an emphysema severity score and assessed upper lobe predominance, using a methodology similar to that of the National Emphysema Treatment Trial. In addition, the percentage of emphysema at -910 Hounsfield units was objectively determined by density mask analysis. RESULTS For the emphysema severity scores, (Spearman) correlation between readers ranged from 0.59 (p = 0.0005) to 0.87 (p < 0.0001), with generally stronger correlations among readers from the same medical specialty. Emphysema severity scores were significantly correlated with prebronchodilator and postbronchodilator spirometry findings, as well as with density mask analysis. In the assessment of upper lobe predominance, kappa statistics for agreement ranged from 0.20 (p = 0.4) to 0.60 (p = 0.0008). Examining all possible radiologist-pulmonologist pairs, the two readers agreed in their assessments of emphysema distribution in 75% of the comparisons. Readers agreed on upper lobe-predominant disease in 9 of the 10 patients in which regional density mask analysis clearly showed upper lobe predominance. CONCLUSIONS In a group of patients with varying emphysema severity, interobserver agreement in the determination of upper lobe-predominant disease was poor. Agreement between readers tended to be better in cases with clear upper lobe predominance as determined by densitometry.
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Affiliation(s)
- Craig P Hersh
- Channing Laboratory, Brigham and Women's Hospital, 181 Longwood Ave, Boston, MA 02115, USA.
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Ito I, Nagai S, Handa T, Muro S, Hirai T, Tsukino M, Mishima M. Matrix metalloproteinase-9 promoter polymorphism associated with upper lung dominant emphysema. Am J Respir Crit Care Med 2005; 172:1378-82. [PMID: 16126934 DOI: 10.1164/rccm.200506-953oc] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Matrix metalloproteinase 9 (MMP-9) has proteolytic activity against connective tissue proteins and appears to play an important role in the development of chronic obstructive pulmonary disease (COPD). The functional polymorphism of MMP-9 (C-1562T) is considered as one of the candidate genes in the susceptibility to COPD. OBJECTIVES To determine if MMP-9 (C-1562T) is related to the development of COPD in the Japanese population and whether it is associated with development of pulmonary emphysema assessed by high-resolution computed tomographic (HRCT) parameters. METHODS MMP-9 (C-1562T) genotypes of 84 patients with COPD and 85 healthy smokers (control subjects) were determined by the restriction fragment length polymorphism method. We investigated the relationship between the genotypes using automatically analyzed HRCT parameters, such as percentage of low attenuation area (LAA%) and average computed tomography (CT) value density (Hounsfield units; mean CTv) in upper, middle, and lower lung fields in all patients with COPD. MEASUREMENTS AND MAIN RESULTS There was no difference in polymorphism of MMP-9 (C-1562T) between patients with COPD and control subjects. In the HRCT study, patients with COPD with a T allele (C/T or T/T) showed larger LAA% (95% confidence interval of difference, 0.5-18.7; p = 0.04), and smaller mean CTv (confidence interval, -34.3 to -1.0; p = 0.04) in the upper lung compared with patients without T alleles (C/C). However, pulmonary function tests showed no difference between the two patient groups. Patients with a T allele showed a decrease in LAA% and an increase in mean CTv from upper to lower lung fields (p = 0.006 and p = 0.002, respectively). CONCLUSIONS Polymorphism of MMP-9 (C-1562T) was associated with upper lung dominant emphysema in patients with COPD.
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Affiliation(s)
- Isao Ito
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Shogoin-kawaharacho 54, Sakyo-ku, Kyoto, 606-8507, Japan.
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Parr DG, Stoel BC, Stolk J, Stockley RA. Pattern of emphysema distribution in alpha1-antitrypsin deficiency influences lung function impairment. Am J Respir Crit Care Med 2004; 170:1172-8. [PMID: 15306534 DOI: 10.1164/rccm.200406-761oc] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
FEV(1) is fundamental to the diagnosis and staging of chronic obstructive pulmonary disease. In emphysema, airflow obstruction usually coexists with impairment of gas exchange, but discordance is not infrequent. We hypothesized that variations in the distribution of emphysema would be associated with functional differences and therefore account for discordant physiology. We used quantitative computed tomography to assess emphysema severity and distribution in 119 subjects with alpha1-antitrypsin deficiency (PiZ phenotype) and grouped them according to distribution pattern. In the 102 subjects with emphysema, 65 had a predominantly basal pattern ("basal"), but 37 (36%) had greater involvement of the upper regions ("apical"). Subjects from each group were matched for total volume of emphysema and age, and matched pairs analysis was used to relate emphysema distribution to clinical phenotype. Basal distribution was associated with greater impairment of FEV(1) (mean difference, 9.9% predicted; 95% confidence interval, 3.8 to 16.0; p = 0.002) but less impairment of gas exchange (Pa(O(2)) mean difference, 0.5 kPa, 0.03 to 0.1; p = 0.016) and alveolar-arterial oxygen gradient (mean difference, 0.7 kPa; 0.2 to 1.2; p = 0.007) than the apical distribution. Emphysema distribution correlated with physiologic discordance (r = -0.409, p < 0.001). The use of single physiologic parameters as a surrogate measure of emphysema severity may introduce systematic bias in the staging of subjects with emphysema.
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Affiliation(s)
- David G Parr
- Lung Investigation Unit, First Floor, Nuffield House, Queen Elizabeth Hospital, Birmingham, UK B15 2TH
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Madani A, Keyzer C, Gevenois PA. Quantitative computed tomography assessment of lung structure and function in pulmonary emphysema. Eur Respir J 2001; 18:720-30. [PMID: 11716178 DOI: 10.1183/09031936.01.00255701] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Accurate diagnosis and quantification of pulmonary emphysema during life is important to understand the natural history of the disease, to assess the extent of the disease, and to evaluate and follow-up therapeutic interventions. Since pulmonary emphysema is defined through pathological criteria, new methods of diagnosis and quantification should be validated by comparisons against histological references. Recent studies have addressed the capability of computed tomography (CT) to quantify pulmonary emphysema accurately. The studies reviewed in this article have been based on CT scans obtained after deep inspiration or expiration, on subjective visual grading and on objective measurements of attenuation values. Especially dedicated software was used for this purpose, which provided numerical data, on both two- and three-dimensional approaches, and compared CT data with pulmonary function tests. More recently, fractal and textural analyses were applied to computed tomography scans to assess the presence, the extent, and the types of emphysema. Quantitative computed tomography has already been used in patient selection for surgical treatment of pulmonary emphysema and in pharmacotherapeutical trials. However, despite numerous and extensive studies, this technique has not yet been standardized and important questions about how best to use computed tomography for the quantification of pulmonary emphysema are still unsolved.
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Affiliation(s)
- A Madani
- Dept of Radiology, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
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Blechschmidt RA, Werthschützky R, Lörcher U. Automated CT image evaluation of the lung: a morphology-based concept. IEEE TRANSACTIONS ON MEDICAL IMAGING 2001; 20:434-442. [PMID: 11403202 DOI: 10.1109/42.925296] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
UNLABELLED Computed tomography (CT) provides the most reliable method to detect emphysema in vivo. Commonly used methods only calculate the area of low attenuation [pixel index (PI)], while a radiologist considers the bullous morphology of emphysema. The PI is a good, well-known measure of emphysema. But it is not able to detect emphysema in cases in which emphysema and fibrosis occur at the same time. This is because fibrosis leads to a low number of low-attenuation pixels, while emphysema leads to a high number of pixels. The PI takes the average of both and, consequently, may present a result within the normal range. METHOD The main focus of this paper is to present a new algorithm of thoracic CT image evaluation based on pulmonary morphology of emphysema. The PI is extended, in that it is enabled to differentiate between small, medium, and large bullae (continuous low-attenuation areas). It is not a texture-based algorithm. The bullae are sorted by size into four size classes: class 1 being within the typical size of lung parenchyma; classes 2-4 presenting small, medium, and large bullae. It is calculated how much area the different classes take up of all low-attenuation pixels. The bullae index (BI) is derived from the percentage of areas covered, respectively, by small, medium, and large bullae. From the relation of the area of bullae belonging to class 4, to that of those belonging to class 2, a measure of the emphysema type (ET)is calculated. It classifies the lung by the type of emphysema in bullous emphysema or small-sized, diffuse emphysema, respectively. RESULTS The BI is as reliable as the PI. In cases in which the PI indicates normal values while in fact emphysema is coexisting with fibrosis, the BI, nevertheless, detects the destruction caused by the emphysema. The BI combined with the ET reflects the visual assessment of the radiological expert. CONCLUSION The BI is an objective and reliable index in order to quantify emphysematous destruction, hence, avoiding interobserver variance. This is particularly interesting for follow-up. The classification of the ET is a helpful and unique approach to achieving an exact diagnosis of emphysema.
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Affiliation(s)
- R A Blechschmidt
- University of Technology, Department of Electrical Engineering and Information Technology, Darmstadt, Germany.
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