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Donovan GM. Pillars of Theoretical Biology: Airway stability and heterogeneity in the constricted lung. J Theor Biol 2023; 575:111628. [PMID: 37778618 DOI: 10.1016/j.jtbi.2023.111628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, 1142, New Zealand.
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2
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Xu Y, Souza LF, Silva IC, Marques AG, Silva FH, Nunes VX, Han T, Jia C, de Albuquerque VHC, Filho PPR. A soft computing automatic based in deep learning with use of fine-tuning for pulmonary segmentation in computed tomography images. Appl Soft Comput 2021. [DOI: 10.1016/j.asoc.2021.107810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lim JU, Lee JS, Lee JH, Lee SD, Oh YM, Rhee CK. Clinical impact of long-term change in air trapping on pulmonary function and computed tomography parameters in chronic obstructive pulmonary disease. Korean J Intern Med 2021; 36:636-646. [PMID: 33232591 PMCID: PMC8137389 DOI: 10.3904/kjim.2019.425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/27/2020] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND/AIMS Air trapping is associated with unfavorable outcomes in chronic obstructive pulmonary disease (COPD). The present study evaluated the association between longitudinal changes in air trapping with pulmonary function, computed tomography (CT) parameters and exacerbation. METHODS Patients enrolled in the Korean Obstructive Lung Disease (KOLD) study cohort from June 2005 to October 2015 were included. The study patients were categorized into four groups according to the change in residual volume to total lung capacity ratio (RV/TLC) over 3 years. The RV/TLC was considered abnormal when it was ≥ 40% and normal when it was < 40%. RESULTS A total of 279 patients were categorized into four groups: 76 in the "normal to normal" (N→N) group, 34 in the "abnormal to normal" (A→N) group, 33 in the "normal to abnormal" (N→A) group, and 136 in the "abnormal to abnormal" (A→A) group. For forced expiratory volume in 1 second and forced vital capacity (FVC), respectively, group A→N showed a large increase of 266 mL (p < 0.001) and 381 mL (p < 0.001), group N→A showed a marked decrease of 216 mL (p < 0.001) and 332 mL(p = 0.029), and group A→A showed a decrease of 16 mL (p = 0.426) and 6 mL (p = 0.011) compared to group N→N. Group A→N showed a significant decrease of -0.013 in expiratory to inspiratory ratio of the mean lung density (p < 0.001), while group A→N showed an increase of 0.005 (p < 0.001). CONCLUSION Patients with COPD whose RV/TLC changed from normal to abnormal showed deterioration of pulmonary function and worsening of CT parameters simultaneously.
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Affiliation(s)
- Jeong Uk Lim
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul,
Korea
| | - Jae Seung Lee
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
| | - Ji-Hyun Lee
- Department of Internal Medicine, Bundang CHA Medical Center, CHA University College of Medicine, Seongnam,
Korea
| | - Sang-Do Lee
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
| | - Yeon-Mok Oh
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
| | - Chin Kook Rhee
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul,
Korea
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Guerra S, Lombardi E, Stern DA, Sherrill DL, Gilbertson-Dahdal D, Wheatley-Guy CM, Snyder EM, Wright AL, Martinez FD, Morgan WJ. Fetal Origins of Asthma: A Longitudinal Study from Birth to Age 36 Years. Am J Respir Crit Care Med 2020; 202:1646-1655. [PMID: 32649838 PMCID: PMC7737573 DOI: 10.1164/rccm.202001-0194oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/10/2020] [Indexed: 11/16/2022] Open
Abstract
Rationale: Deficits in infant lung function-including the ratio of the time to reach peak tidal expiratory flow to the total expiratory time (tptef/te) and maximal expiratory flow at FRC (V̇maxFRC)-have been linked to increased risk for childhood asthma.Objectives: To examine the individual and combined effects of tptef/te and V̇maxFRC in infancy on risk for asthma and abnormalities of airway structure into mid-adult life.Methods: One hundred eighty participants in the Tucson Children's Respiratory Study birth cohort had lung function measured by the chest-compression technique in infancy (mean age ± SD: 2.0 ± 1.2 mo). Active asthma was assessed in up to 12 questionnaires between ages 6 and 36 years. Spirometry and chest high-resolution computed tomographic (HRCT) imaging were completed in a subset of participants at age 26. The relations of infant tptef/te and V̇maxFRC to active asthma and airway structural abnormalities into adult life were tested in multivariable mixed models.Measurements and Main Results: After adjustment for covariates, a 1-SD decrease in infant tptef/te and V̇maxFRC was associated with a 70% (P = 0.001) and 55% (P = 0.005) increased risk of active asthma, respectively. These effects were partly independent, and two out of three infants who were in the lowest tertile for both tptef/te and V̇maxFRC developed active asthma by mid-adult life. Infant V̇maxFRC predicted reduced airflow and infant tptef/te reduced HRCT airway caliber at age 26.Conclusions: These findings underscore the long-lasting effects of the fetal origins of asthma, support independent contributions by infant tptef/te and V̇maxFRC to development of asthma, and link deficits at birth in tptef/te with HRCT-assessed structural airway abnormalities in adult life.
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Affiliation(s)
- Stefano Guerra
- Asthma and Airway Disease Research Center
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, College of Medicine – Tucson
- Mel and Enid Zuckerman College of Public Health
| | - Enrico Lombardi
- Asthma and Airway Disease Research Center
- Department of Medical Imaging, College of Medicine – Tucson, and
| | | | - Duane L. Sherrill
- Asthma and Airway Disease Research Center
- Department of Pediatrics, University of Arizona, Tucson, Arizona
| | | | | | - Eric M. Snyder
- Department of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona; and
| | | | | | - Wayne J. Morgan
- Asthma and Airway Disease Research Center
- Geneticure, Rochester, Minnesota
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Nadeem SA, Hoffman EA, Comellas AP, Saha PK. LOCALLY ADAPTIVE HALF-MAX METHODS FOR AIRWAY LUMEN-AREA AND WALL-THICKNESS AND THEIR REPEAT CT SCAN REPRODUCIBILITY. PROCEEDINGS. IEEE INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING 2020; 2020:10.1109/isbi45749.2020.9098558. [PMID: 34422222 PMCID: PMC8375398 DOI: 10.1109/isbi45749.2020.9098558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Quantitative computed tomography (CT)-based characterization of bronchial metrics is increasingly being used to investigate chronic obstructive pulmonary disease (COPD)-related phenotypes. Automated methods for airway measurements benefit large multi-site studies by reducing cost and subjectivity errors. Critical challenges for CT-based analysis of airway morphology are related to location of lumen and wall transitions in the presence of varying scales and intensity-contrasts from proximal to distal sites. This paper introduces locally adaptive half-max methods to locate airway lumen and wall transitions and compute cross-sectional lumen area and wall-thickness. Also, the method uses a consistency analysis of wall-thickness to avoid adjoining-structure-artifacts. Experimental results show that computed bronchial measures at individual anatomic airway tree locations are repeat CT scan reproducible with intra-class correlation coefficient (ICC) values exceeding 0.9 and 0.8 for lumen-area and wall-thickness, respectively. Observed ICC values for derived morphologic measures, e.g., lumen-area compactness (ICC>0.67) and tapering (ICC>0.47) are relatively lower.
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Affiliation(s)
- Syed Ahmed Nadeem
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Eric A Hoffman
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Alejandro P Comellas
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Punam K Saha
- Department of Electrical and Computer Engineering, College of Engineering, University of Iowa, Iowa City, IA 52242, USA
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Lim JU, Kim EK, Lim SY, Lee JH, Lee JS, Lee SD, Oh YM, Rhee CK. Mixed Phenotype of Emphysema and Airway Wall Thickening Is Associated with Frequent Exacerbation in Chronic Obstructive Pulmonary Disease Patients. Int J Chron Obstruct Pulmon Dis 2019; 14:3035-3042. [PMID: 31920300 PMCID: PMC6941609 DOI: 10.2147/copd.s227377] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 12/17/2019] [Indexed: 12/20/2022] Open
Abstract
Objective The presence of both emphysema and airway wall thickening determined via volumetric computed tomography (CT) is defined as mixed phenotype. The long-term clinical course of this phenotype has not been studied in depth. This study compared the mixed phenotype to other phenotypes of chronic obstructive pulmonary disease (COPD) patients. Methods COPD patients enrolled in the Korean Obstructive Lung Disease (KOLD) study from June 2005 to October 2015 were evaluated. The emphysema index and the percentage of bronchial mean wall area were calculated from volumetric CT scans. Patients with COPD were classified into four phenotypes using two cutoffs: emphysema index of 15% and median value of mean wall area (MWA%). Results Of 435 patients with COPD, 99 (22.8%) were defined as CT-normal type, 119 (27.4%) as emphysema-dominant type, 113 (26.0%) as airway-dominant type, and 104 (23.9%) as mixed type. The mixed phenotype showed the highest baseline total COPD Assessment Test (CAT) and St. George’s Respiratory Questionnaire (SGRQ) scores. Moreover, it had the highest proportion of patients experiencing exacerbation of COPD (50.0%), and had the lowest baseline FEV1. Lower BMI, GOLD stages III–IV, and mixed phenotype were significant factors associated with severe exacerbation frequency in univariate analyses. Multivariate analyses showed that lower BMI and CT phenotype were significant factors associated with severe exacerbation frequency. Compared to the CT-normal phenotype, the mixed phenotype was significantly associated with more frequent severe exacerbation (IRR 4.134, 95% CI: 1.135–15.057, P=0.031). Conclusion Patients with mixed phenotype are more symptomatic, have poorer pulmonary function, and are associated with more frequent severe exacerbation.
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Affiliation(s)
- Jeong Uk Lim
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Eun Kyung Kim
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi-do, South Korea
| | - Seong Yong Lim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jin Hwa Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Ewha Womans University, Seoul, South Korea
| | - Jae Seung Lee
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Sang-Do Lee
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Yeon-Mok Oh
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Chin Kook Rhee
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
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Lim JU, Lee JH, Kim TH, Lee JS, Lee SD, Oh YM, Rhee CK. Alternative definitions of chronic bronchitis and their correlation with CT parameters. Int J Chron Obstruct Pulmon Dis 2018; 13:1893-1899. [PMID: 29942122 PMCID: PMC6005312 DOI: 10.2147/copd.s164055] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Introduction Phenotyping of chronic bronchitis (CB) using COPD assessment tool (CAT) scores and St George's Respiratory Questionnaire (SGRQ) has rarely been attempted. The present study defined CB using CAT 1 and 2 scores and the questions on the severity of cough and sputum from the SGRQ. Furthermore, the predictability of CT parameters was also assessed for each CB definition. Materials and methods Patients enrolled in the Korean Obstructive Lung Disease study from June 2005 to October 2015 were evaluated for this study. The patients were spirometrically diagnosed with COPD and had a smoking history of >10 pack-years. Volumetric CT scans were performed for each patient upon enrollment in the cohort. Two definitions of CB using CAT 1/2 scores and SGRQ questions were used to phenotype CB among the study patients. Receiver operating characteristic curve analysis was performed to estimate the predictability of CT parameters for the CB phenotypes. Results Using CAT 1/2 scores, 57 of 279 (20.4%) patients had CB, and 178 of 573 (31.1%) had CB when the SGRQ questions were used to phenotype it. Total CAT and SGRQ scores were significantly higher in the CB group than those in the non-CB group for both definitions of CB. Forced expiratory volume in 1 second was lower for both CAT-defined and SGRQ-defined CB than that in the non-CB group. Mean wall thickness was significantly higher for both CB groups than in the non-CB group. Expiratory lung volume was higher and mean lung density was significantly lower for the SGRQ-defined CB group than non-CB group. Conclusion The 2 CB definitions using CAT scores and the SGRQ questions correlated with associated CT airway parameters. SGRQ-defined CB better reflected the accompaniment of small airway obstruction when compared with CAT-defined CB.
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Affiliation(s)
- Jeong Uk Lim
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Ji-Hyun Lee
- Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Tae-Hyung Kim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Guri, Korea
| | - Jae Seung Lee
- Department of Pulmonary and Critical Care Medicine and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sang-Do Lee
- Department of Pulmonary and Critical Care Medicine and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Yeon-Mok Oh
- Department of Pulmonary and Critical Care Medicine and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Chin Kook Rhee
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Chung H, Ko H, Jeon SJ, Yoon KH, Lee J. Automatic Lung Segmentation With Juxta-Pleural Nodule Identification Using Active Contour Model and Bayesian Approach. IEEE JOURNAL OF TRANSLATIONAL ENGINEERING IN HEALTH AND MEDICINE-JTEHM 2018; 6:1800513. [PMID: 29910995 PMCID: PMC6001848 DOI: 10.1109/jtehm.2018.2837901] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 03/28/2018] [Accepted: 05/06/2018] [Indexed: 11/07/2022]
Abstract
OBJECTIVE chest computed tomography (CT) images and their quantitative analyses have become increasingly important for a variety of purposes, including lung parenchyma density analysis, airway analysis, diaphragm mechanics analysis, and nodule detection for cancer screening. Lung segmentation is an important prerequisite step for automatic image analysis. We propose a novel lung segmentation method to minimize the juxta-pleural nodule issue, a notorious challenge in the applications. METHOD we initially used the Chan-Vese (CV) model for active lung contours and adopted a Bayesian approach based on the CV model results, which predicts the lung image based on the segmented lung contour in the previous frame image or neighboring upper frame image. Among the resultant juxta-pleural nodule candidates, false positives were eliminated through concave points detection and circle/ellipse Hough transform. Finally, the lung contour was modified by adding the final nodule candidates to the area of the CV model results. RESULTS to evaluate the proposed method, we collected chest CT digital imaging and communications in medicine images of 84 anonymous subjects, including 42 subjects with juxta-pleural nodules. There were 16 873 images in total. Among the images, 314 included juxta-pleural nodules. Our method exhibited a disc similarity coefficient of 0.9809, modified hausdorff distance of 0.4806, sensitivity of 0.9785, specificity of 0.9981, accuracy of 0.9964, and juxta-pleural nodule detection rate of 96%. It outperformed existing methods, such as the CV model used alone, the normalized CV model, and the snake algorithm. Clinical impact: the high accuracy with the juxta-pleural nodule detection in the lung segmentation can be beneficial for any computer aided diagnosis system that uses lung segmentation as an initial step.
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Affiliation(s)
- Heewon Chung
- Department of Biomedical EngineeringWonkwang University College of MedicineIksan54538South Korea
| | - Hoon Ko
- Department of Biomedical EngineeringWonkwang University College of MedicineIksan54538South Korea
| | - Se Jeong Jeon
- Department of RadiologyWonkwang University College of MedicineIksan54538South Korea
| | - Kwon-Ha Yoon
- Department of RadiologyWonkwang University College of MedicineIksan54538South Korea
| | - Jinseok Lee
- Department of Biomedical EngineeringWonkwang University College of MedicineIksan54538South Korea
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Brown RH, Togias A. Measurement of intraindividual airway tone heterogeneity and its importance in asthma. J Appl Physiol (1985) 2016; 121:223-32. [PMID: 27103654 PMCID: PMC4967252 DOI: 10.1152/japplphysiol.00545.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 04/20/2016] [Indexed: 11/22/2022] Open
Abstract
While airways have some degree of baseline tone, the level and variability of this tone is not known. It is also unclear whether there is a difference in airway tone or in the variability of airway tone between asthmatic and healthy individuals. This study examined airway tone and intraindividual airway tone heterogeneity (variance of airway tone) in vivo in 19 individuals with asthma compared with 9 healthy adults. All participants underwent spirometry, body plethysmography, and high-resolution computed tomography at baseline and after maximum bronchodilation with albuterol. Airway tone was defined as the percent difference in airway diameter after albuterol at total lung capacity compared with baseline. The amount of airway tone in each airway varied both within and between subjects. The average airway tone did not differ significantly between the two groups (P = 0.09), but the intraindividual airway tone heterogeneity did (P = 0.016). Intraindividual airway tone heterogeneity was strongly correlated with airway tone (r = 0.78, P < 0.0001). Also, it was negatively correlated with the magnitude of the distension of the airways from functional residual capacity to total lung capacity at both baseline (r = −0.49, P = 0.03) and after maximum bronchodilation (r = −0.51, P = 0.02) in the asthma, but not the healthy group. However, we did not find any relationship between intraindividual airway tone heterogeneity and conventional lung function outcomes. Intraindividual airway tone heterogeneity appears to be an important characteristic of airway pathophysiology in asthma.
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Affiliation(s)
- Robert H Brown
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland; Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland; Department of Environmental Health Sciences, Division of Physiology, Johns Hopkins University, Baltimore, Maryland; Department of Radiology, Johns Hopkins University, Baltimore, Maryland; and
| | - Alkis Togias
- Department of Medicine, Divisions of Allergy and Clinical Immunology and Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
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10
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Effect of Reducing Field of View on Multidetector Quantitative Computed Tomography Parameters of Airway Wall Thickness in Asthma. J Comput Assist Tomogr 2015; 39:584-90. [PMID: 25938213 DOI: 10.1097/rct.0000000000000238] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE We reduced the computed tomography (CT)-reconstructed field of view (FOV), increasing pixel density across airway structures and reducing partial volume effects, to determine whether this would improve accuracy of airway wall thickness quantification. METHODS We performed CT imaging on a lung phantom and 29 participants. Images were reconstructed at 30-, 15-, and 10-cm FOV using a medium-smooth kernel. Cross-sectional airway dimensions were compared at each FOV with repeated-measures analysis of variance. RESULTS Phantom measurements were more accurate when FOV decreased from 30 to 15 cm (P < 0.05). Decreasing FOV further to 10 cm did not significantly improve accuracy. Human airway measurements similarly decreased by decreasing FOV (P < 0.001). Percent changes in all measurements when reducing FOV from 30 to 15 cm were less than 3%. CONCLUSIONS Airway measurements at 30-cm FOV are near the limits of CT resolution using a medium-smooth kernel. Reducing reconstructed FOV would minimally increase sensitivity to detect differences in airway dimensions.
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11
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Rodriguez A, Ranallo FN, Judy PF, Gierada DS, Fain SB. CT reconstruction techniques for improved accuracy of lung CT airway measurement. Med Phys 2015; 41:111911. [PMID: 25370644 DOI: 10.1118/1.4898098] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To determine the impact of constrained reconstruction techniques on quantitative CT (qCT) of the lung parenchyma and airways for low x-ray radiation dose. METHODS Measurement of small airways with qCT remains a challenge, especially for low x-ray dose protocols. Images of the COPDGene quality assurance phantom (CTP698, The Phantom Laboratory, Salem, NY) were obtained using a GE discovery CT750 HD scanner for helical scans at x-ray radiation dose-equivalents ranging from 1 to 4.12 mSv (12-100 mA s current-time product). Other parameters were 40 mm collimation, 0.984 pitch, 0.5 s rotation, and 0.625 mm thickness. The phantom was sandwiched between 7.5 cm thick water attenuating phantoms for a total length of 20 cm to better simulate the scatter conditions of patient scans. Image data sets were reconstructed using STANDARD (STD), DETAIL, BONE, and EDGE algorithms for filtered back projection (FBP), 100% adaptive statistical iterative reconstruction (ASIR), and Veo reconstructions. Reduced (half) display field of view (DFOV) was used to increase sampling across airway phantom structures. Inner diameter (ID), wall area percent (WA%), and wall thickness (WT) measurements of eight airway mimicking tubes in the phantom, including a 2.5 mm ID (42.6 WA%, 0.4 mm WT), 3 mm ID (49.0 WA%, 0.6 mm WT), and 6 mm ID (49.0 WA%, 1.2 mm WT) were performed with Airway Inspector (Surgical Planning Laboratory, Brigham and Women's Hospital, Boston, MA) using the phase congruency edge detection method. The average of individual measures at five central slices of the phantom was taken to reduce measurement error. RESULTS WA% measures were greatly overestimated while IDs were underestimated for the smaller airways, especially for reconstructions at full DFOV (36 cm) using the STD kernel, due to poor sampling and spatial resolution (0.7 mm pixel size). Despite low radiation dose, the ID of the 6 mm ID airway was consistently measured accurately for all methods other than STD FBP. Veo reconstructions showed slight improvement over STD FBP reconstructions (4%-9% increase in accuracy). The most improved ID and WA% measures were for the smaller airways, especially for low dose scans reconstructed at half DFOV (18 cm) with the EDGE algorithm in combination with 100% ASIR to mitigate noise. Using the BONE + ASIR at half BONE technique, measures improved by a factor of 2 over STD FBP even at a quarter of the x-ray dose. CONCLUSIONS The flexibility of ASIR in combination with higher frequency algorithms, such as BONE, provided the greatest accuracy for conventional and low x-ray dose relative to FBP. Veo provided more modest improvement in qCT measures, likely due to its compatibility only with the smoother STD kernel.
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Affiliation(s)
- A Rodriguez
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705
| | - F N Ranallo
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792
| | - P F Judy
- Brigham and Women's Hospital, Boston, Massachusetts 02115
| | - D S Gierada
- Department of Radiology, Washington University, St. Louis, Missouri 63110
| | - S B Fain
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705; Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792; and Department of Biomedical Engineering,University of Wisconsin School of Engineering, Madison, Wisconsin 53706
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12
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Xu Z, Bagci U, Foster B, Mansoor A, Udupa JK, Mollura DJ. A hybrid method for airway segmentation and automated measurement of bronchial wall thickness on CT. Med Image Anal 2015; 24:1-17. [PMID: 26026778 DOI: 10.1016/j.media.2015.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 09/04/2014] [Accepted: 05/05/2015] [Indexed: 11/29/2022]
Abstract
Inflammatory and infectious lung diseases commonly involve bronchial airway structures and morphology, and these abnormalities are often analyzed non-invasively through high resolution computed tomography (CT) scans. Assessing airway wall surfaces and the lumen are of great importance for diagnosing pulmonary diseases. However, obtaining high accuracy from a complete 3-D airway tree structure can be quite challenging. The airway tree structure has spiculated shapes with multiple branches and bifurcation points as opposed to solid single organ or tumor segmentation tasks in other applications, hence, it is complex for manual segmentation as compared with other tasks. For computerized methods, a fundamental challenge in airway tree segmentation is the highly variable intensity levels in the lumen area, which often causes a segmentation method to leak into adjacent lung parenchyma through blurred airway walls or soft boundaries. Moreover, outer wall definition can be difficult due to similar intensities of the airway walls and nearby structures such as vessels. In this paper, we propose a computational framework to accurately quantify airways through (i) a novel hybrid approach for precise segmentation of the lumen, and (ii) two novel methods (a spatially constrained Markov random walk method (pseudo 3-D) and a relative fuzzy connectedness method (3-D)) to estimate the airway wall thickness. We evaluate the performance of our proposed methods in comparison with mostly used algorithms using human chest CT images. Our results demonstrate that, on publicly available data sets and using standard evaluation criteria, the proposed airway segmentation method is accurate and efficient as compared with the state-of-the-art methods, and the airway wall estimation algorithms identified the inner and outer airway surfaces more accurately than the most widely applied methods, namely full width at half maximum and phase congruency.
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Affiliation(s)
- Ziyue Xu
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Science Department, National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Ulas Bagci
- Center for Research in Computer Vision (CRCV), Department of Computer Science, University of Central Florida (UCF), Orlando, FL 32816, United States.
| | - Brent Foster
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Science Department, National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Awais Mansoor
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Science Department, National Institutes of Health (NIH), Bethesda, MD 20892, United States
| | - Jayaram K Udupa
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Daniel J Mollura
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Science Department, National Institutes of Health (NIH), Bethesda, MD 20892, United States
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Hoegger MJ, Fischer AJ, McMenimen JD, Ostedgaard LS, Tucker AJ, Awadalla MA, Moninger TO, Michalski AS, Hoffman EA, Zabner J, Stoltz DA, Welsh MJ. Impaired mucus detachment disrupts mucociliary transport in a piglet model of cystic fibrosis. Science 2014; 345:818-22. [PMID: 25124441 DOI: 10.1126/science.1255825] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Lung disease in people with cystic fibrosis (CF) is initiated by defective host defense that predisposes airways to bacterial infection. Advanced CF is characterized by a deficit in mucociliary transport (MCT), a process that traps and propels bacteria out of the lungs, but whether this deficit occurs first or is secondary to airway remodeling has been unclear. To assess MCT, we tracked movement of radiodense microdisks in airways of newborn piglets with CF. Cholinergic stimulation, which elicits mucus secretion, substantially reduced microdisk movement. Impaired MCT was not due to periciliary liquid depletion; rather, CF submucosal glands secreted mucus strands that remained tethered to gland ducts. Inhibiting anion secretion in non-CF airways replicated CF abnormalities. Thus, impaired MCT is a primary defect in CF, suggesting that submucosal glands and tethered mucus may be targets for early CF treatment.
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Affiliation(s)
- Mark J Hoegger
- Department of Molecular Physiology and Biophysics, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Anthony J Fischer
- Department of Pediatrics, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - James D McMenimen
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Lynda S Ostedgaard
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Alex J Tucker
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Maged A Awadalla
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Thomas O Moninger
- Central Microscopy Research Facility, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Andrew S Michalski
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Eric A Hoffman
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. Department of Radiology, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Joseph Zabner
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - David A Stoltz
- Department of Molecular Physiology and Biophysics, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA.
| | - Michael J Welsh
- Department of Molecular Physiology and Biophysics, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. Howard Hughes Medical Institute (HHMI), University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA.
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Abstract
Assessing airway wall surfaces and the lumen from high resolution computed tomography (CT) scans are of great importance for diagnosing pulmonary diseases. However, accurately determining inner and outer airway wall surfaces of a complete 3-D tree structure can be quite challenging because of its complex nature. In this paper, we introduce a computational framework to accurately quantify airways through (i) a precise segmentation of the lumen, and (ii) a spatially constrained Markov random walk method to estimate the airway walls. Our results demonstrate that the proposed airway analysis platform identified the inner and outer airway surfaces better than methods commonly used in clinics, such as full width at half maximum and phase congruency.
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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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Liu X, Chen DZ, Tawhai MH, Wu X, Hoffman EA, Sonka M. Optimal graph search based segmentation of airway tree double surfaces across bifurcations. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:493-510. [PMID: 23070299 PMCID: PMC4086865 DOI: 10.1109/tmi.2012.2223760] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Identification of both the luminal and the wall areas of the bronchial tree structure from volumetric X-ray computed tomography (CT) data sets is of critical importance in distinguishing important phenotypes within numerous major lung diseases including chronic obstructive pulmonary diseases (COPD) and asthma. However, accurate assessment of the inner and outer airway wall surfaces of a complete 3-D tree structure is difficult due to their complex nature, particularly around the branch areas. In this paper, we extend a graph search based technique (LOGISMOS) to simultaneously identify multiple inter-related surfaces of branching airway trees. We first perform a presegmentation of the input 3-D image to obtain basic information about the tree topology. The presegmented image is resampled along judiciously determined paths to produce a set of vectors of voxels (called voxel columns). The resampling process utilizes medial axes to ensure that voxel columns of appropriate lengths and directions are used to capture the object surfaces without interference. A geometric graph is constructed whose edges connect voxels in the resampled voxel columns and enforce validity of the smoothness and separation constraints on the sought surfaces. Cost functions with directional information are employed to distinguish inner and outer walls. The assessment of wall thickness measurement on a CT-scanned double-wall physical phantom (patterned after an in vivo imaged human airway tree) achieved highly accurate results on the entire 3-D tree. The observed mean signed error of wall thickness ranged from -0.09 ±0.24 mm to 0.07 ±0.23 mm in bifurcating/nonbifurcating areas. The mean unsigned errors were 0.16±0.12 mm to 0.20±0.11 mm. When the airway wall surface was partitioned into meaningful subregions, the airway wall thickness accuracy was the same in most tested bifurcation/nonbifurcation and carina/noncarina regions (p=NS). Once validated on phantoms, our method was applied to human in vivo volumetric CT data to demonstrate relationships of airway wall thickness as a function of luminal dimension and airway tree generation. Wall thickness differences between the bifurcation/nonbifurcation regions were statistically significant (p < 0.05) for tree generations 6, 7, 8, and 9. In carina/noncarina regions, the wall thickness was statistically different in generations 1, 4, 5, 6, 7, and 8.
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Affiliation(s)
- Xiaomin Liu
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
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CT attenuation of the bronchial wall in patients with asthma: comparison with geometric parameters and correlation with function and histologic characteristics. AJR Am J Roentgenol 2013; 199:1226-33. [PMID: 23169712 DOI: 10.2214/ajr.11.8396] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purposes of this study were to compare airway wall attenuation in subjects with asthma and subjects without asthma; to correlate this value with pulmonary function test results, standard bronchial CT parameters, and immunohistologic data; and to identify CT parameters that influence obstructive indexes. SUBJECTS AND METHODS Bronchial airway wall attenuation was averaged over four bronchi in 27 subjects with asthma and 15 control subjects without asthma. The following five standard bronchial parameters also were assessed: lumen area, wall area, wall thickness, wall-to-lumen area ratio, and wall-to-total area ratio (wall area percentage). These parameters were compared between groups and correlated with functional data. Ability to predict patient group with these parameters was determined by comparison of receiver operating characteristic curves and areas under the curve. The influence of the parameters on obstructive indexes was assessed by multivariate analysis. Correlations between wall attenuation value and histologic data were studied in 11 patients with asthma. RESULTS Wall attenuation value was greater in patients with asthma (-322 ± 79 HU) than in control subjects (-463 ± 69 HU). Correlation coefficients of wall attenuation value with functional obstructive parameters were significant and greater than those obtained for any other CT parameter. The area under the curve of wall attenuation value was greater than that of bronchial lumen area and bronchial wall area. In the model of multiple regression that included wall attenuation value and wall-to-total area ratio, wall attenuation value was the only measurement that significantly influenced obstructive indexes (R(2) = 0.39-0.43). Wall attenuation value correlated with mast cell infiltration. CONCLUSION Compared with the usual bronchial CT parameters, airway wall attenuation better differentiates patients with asthma from control subjects and better correlates with obstruction.
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Mumcuoğlu EU, Long FR, Castile RG, Gurcan MN. Image analysis for cystic fibrosis: computer-assisted airway wall and vessel measurements from low-dose, limited scan lung CT images. J Digit Imaging 2013; 26:82-96. [PMID: 22549245 PMCID: PMC3553364 DOI: 10.1007/s10278-012-9476-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Cystic fibrosis (CF) is a life-limiting genetic disease that affects approximately 30,000 Americans. When compared to those of normal children, airways of infants and young children with CF have thicker walls and are more dilated in high-resolution computed tomographic (CT) imaging. In this study, we develop computer-assisted methods for assessment of airway and vessel dimensions from axial, limited scan CT lung images acquired at low pediatric radiation doses. Two methods (threshold- and model-based) were developed to automatically measure airway and vessel sizes for pairs identified by a user. These methods were evaluated on chest CT images from 16 pediatric patients (eight infants and eight children) with different stages of mild CF related lung disease. Results of threshold-based, corrected with regression analysis, and model-based approaches correlated well with both electronic caliper measurements made by experienced observers and spirometric measurements of lung function. While the model-based approach results correlated slightly better with the human measurements than those of the threshold method, a hybrid method, combining these two methods, resulted in the best results.
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Affiliation(s)
- Erkan U Mumcuoğlu
- Health Informatics Department, Informatics Institute, Middle East Technical University, Ankara, Turkey.
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Hackx M, Bankier AA, Gevenois PA. Chronic obstructive pulmonary disease: CT quantification of airways disease. Radiology 2012; 265:34-48. [PMID: 22993219 DOI: 10.1148/radiol.12111270] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is an increasing cause of morbidity and mortality worldwide and results in substantial social and economic burdens. COPD is a heterogeneous disease with both extrapulmonary and pulmonary components. The pulmonary component is characterized by an airflow limitation that is not fully reversible. In the authors' opinion, none of the currently available classifications combining airflow limitation measurements with clinical parameters is sufficient to determine the prognosis and treatment of a particular patient with COPD. With regard to the causes of airflow limitation, CT can be used to quantify the two main contributions to COPD: emphysema, and small airways disease (a narrowing of the airways). CT quantification--with subsequent COPD phenotyping--can contribute to improved patient care, assessment of COPD progression, and identification of severe COPD with increasing risk of mortality. Small airways disease can be quantified through measurements reflecting morphology, quantification of obstruction, and changes in airways walls. This article details these three approaches and concludes with perspectives and directions for further research.
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Affiliation(s)
- Maxime Hackx
- Department of Radiology, Hôpital Erasme, Université Libre de Bruxelles, 808 Route de Lennik, 1070 Brussels, Belgium
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Donohue KM, Hoffman EA, Baumhauer H, Guo J, Budoff M, Austin JH, Kalhan R, Kawut S, Tracy R, Barr RG. Cigarette smoking and airway wall thickness on CT scan in a multi-ethnic cohort: the MESA Lung Study. Respir Med 2012; 106:1655-64. [PMID: 22974831 PMCID: PMC3549633 DOI: 10.1016/j.rmed.2012.08.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 08/07/2012] [Accepted: 08/10/2012] [Indexed: 01/26/2023]
Abstract
BACKGROUND Autopsy studies show that smoking contributes to airway wall hyperplasia and narrowing of the airway lumen. Studies of smoking and airway measures on computed tomography (CT) scan are limited to case-control studies of measures that combine airway lumen and wall thickness. OBJECTIVES We hypothesized that cumulative cigarette smoking would be associated with increased airway wall thickness in a large, population-based cohort. METHODS The Multi-Ethnic Study of Atherosclerosis enrolled participants age 45-84 years from the general population. Smoking history was assessed via standardized questionnaire items; current smoking was confirmed in half the cohort with cotinine. Airway lumen and wall thickness were measured in two dimensions in posterior basal segmental bronchi on cardiac-gated CT scans. Analyses were adjusted for age, gender, genetic ancestry, education, height, weight, asthma history, particulate matter, scanner type, and scanner current. RESULTS Half of the 7898 participants had smoked and 14% were current smokers. Pack-years of smoking were associated with thicker airway walls (mean increase 0.002 mm per ten pack-years [95% CI: 0.00002, 0.004] p = 0.03). Current smoking was associated with narrower airway lumens (mean decrease -0.11 mm [95% CI: -0.2, -0.02] p = 0.02). There was no evidence that either association was modified by genetic ancestry, and findings persisted among participants without clinical disease. CONCLUSIONS Long-term cigarette smoking was associated with subclinical increases in wall thickness of sub-segmental airways whereas current smoking was associated with narrower airway lumen diameters. Smoking may contribute to airway wall thickening prior to the development of overt chronic obstructive pulmonary disease.
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Affiliation(s)
| | | | | | - Junfeng Guo
- University of Iowa, Iowa City, IA 52242, USA
| | - Matthew Budoff
- Los Angeles Biomedical Research Institute, Torrance, CA 90502, USA
| | | | - Ravi Kalhan
- Northwestern University, Chicago, IL 60611, USA
| | - Steven Kawut
- University of Pennsylvania, Philadelphia, PA 19104, USA
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Mean Bronchial Wall Attenuation Value in Chronic Obstructive Pulmonary Disease: Comparison With Standard Bronchial Parameters and Correlation With Function. AJR Am J Roentgenol 2012; 198:800-8. [DOI: 10.2214/ajr.11.6895] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Sheehy A, Gutiérrez-Chico JL, Diletti R, Oberhauser JP, Glauser T, Harrington J, Kossuth MB, Rapoza RJ, Onuma Y, Serruys PW. In vivo characterisation of bioresorbable vascular scaffold strut interfaces using optical coherence tomography with Gaussian line spread function analysis. EUROINTERVENTION 2012; 7:1227-35. [DOI: 10.4244/eijv7i10a195] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Siddiqui S, Tsuchiya K, Risse PA, Bullimore SR, Benedetti A, Martin JG. Site of allergic airway narrowing and the influence of exogenous surfactant in the Brown Norway rat. PLoS One 2012; 7:e29381. [PMID: 22276110 PMCID: PMC3261862 DOI: 10.1371/journal.pone.0029381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 11/28/2011] [Indexed: 11/18/2022] Open
Abstract
Background The parameters RN (Newtonian resistance), G (tissue damping), and H (tissue elastance) of the constant phase model of respiratory mechanics provide information concerning the site of altered mechanical properties of the lung. The aims of this study were to compare the site of allergic airway narrowing implied from respiratory mechanics to a direct assessment by morphometry and to evaluate the effects of exogenous surfactant administration on the site and magnitude of airway narrowing. Methods We induced airway narrowing by ovalbumin sensitization and challenge and we tested the effects of a natural surfactant lacking surfactant proteins A and D (Infasurf®) on airway responses. Sensitized, mechanically ventilated Brown Norway rats underwent an aerosol challenge with 5% ovalbumin or vehicle. Other animals received nebulized surfactant prior to challenge. Three or 20 minutes after ovalbumin challenge, airway luminal areas were assessed on snap-frozen lungs by morphometry. Results At 3 minutes, RN and G detected large airway narrowing whereas at 20 minutes G and H detected small airway narrowing. Surfactant inhibited RN at the peak of the early allergic response and ovalbumin-induced increase in bronchoalveolar lavage fluid cysteinyl leukotrienes and amphiregulin but not IgE-induced mast cell activation in vitro. Conclusion Allergen challenge triggers the rapid onset of large airway narrowing, detected by RN and G, and subsequent peripheral airway narrowing detected by G and H. Surfactant inhibits airway narrowing and reduces mast cell-derived mediators.
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Affiliation(s)
- Sana Siddiqui
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Kimitake Tsuchiya
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Paul-André Risse
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Sharon R. Bullimore
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Andrea Benedetti
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - James G. Martin
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
- * E-mail:
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Lung imaging in asthmatic patients: the picture is clearer. J Allergy Clin Immunol 2011; 128:467-78. [PMID: 21636118 DOI: 10.1016/j.jaci.2011.04.051] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Revised: 04/10/2011] [Accepted: 04/18/2011] [Indexed: 01/11/2023]
Abstract
Imaging of the lungs in patients with asthma has evolved dramatically over the last decade with sophisticated techniques, such as computed tomography, magnetic resonance imaging, positron emission tomography, and single photon emission computed tomography. New insights into current and future modalities for imaging in asthmatic patients and their application are discussed to potentially shed a clearer picture of the underlying pathophysiology of asthma, especially severe asthma, and the proposed clinical utility of imaging in patients with this common disease.
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Brown RH, Kaczka DW, Fallano K, Shapiro S, Mitzner W. Individual canine airway response variability to a deep inspiration. CLINICAL MEDICINE INSIGHTS-CIRCULATORY RESPIRATORY AND PULMONARY MEDICINE 2011; 5:7-15. [PMID: 21487453 PMCID: PMC3072207 DOI: 10.4137/ccrpm.s6531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In healthy individuals, a DI can reverse (bronchodilation) or prevent (bronchoprotection) induced airway constriction. For individuals with asthma or COPD, these effects may be attenuated or absent. Previous work showed that the size and duration of a DI affected the subsequent response of the airways. Also, increased airway tone lead to increased airway size variability. The present study examined how a DI affected the temporal variability in individual airway baseline size and after methacholine challenge in dogs using High-Resolution Computed Tomography. Dogs were anesthetized and ventilated, and on 4 separate days, HRCT scans were acquired before and after a DI at baseline and during a continuous intravenous infusion of methacholine (Mch) at 3 dose rates (17, 67, and 200 μg/min). The Coefficient of Variation was used as an index of temporal variability in airway size.We found that at baseline and the lowest dose of Mch, variability decreased immediately and 5 minutes after the DI (P < 0.0001). In contrast, with higher doses of Mch, the DI caused a variable response. At a rate of 67 μg/min of Mch, the temporal variability increased after 5 minutes, while at a rate of 200 μg/min of Mch, the temporal variability increased immediately after the DI. Increased airway temporal variability has been shown to be associated with asthma. Although the mechanisms underlying this temporal variability are poorly understood, the beneficial effects of a DI to decrease airway temporal variability was eliminated when airway tone was increased. If this effect is absent in asthmatics, this may suggest a possible mechanism for the loss of bronchoprotective and bronchodilatory effects after a DI in asthma.
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Affiliation(s)
- Robert H Brown
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
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Borges JB, Velikyan I, Långström B, Sörensen J, Ulin J, Maripuu E, Sandström M, Widström C, Hedenstierna G. Ventilation Distribution Studies Comparing Technegas and “Gallgas” Using 68GaCl3 as the Label. J Nucl Med 2011; 52:206-9. [DOI: 10.2967/jnumed.110.083881] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Measuring small airways in transverse CT images correction for partial volume averaging and airway tilt. Acad Radiol 2010; 17:1525-34. [PMID: 20947386 DOI: 10.1016/j.acra.2010.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 07/17/2010] [Accepted: 07/27/2010] [Indexed: 11/21/2022]
Abstract
RATIONALE AND OBJECTIVES Airway wall dimensions can be determined in vivo using transverse computed tomographic (CT) images, but the measurement of airway phantoms shows that the wall thickness is consistently overestimated for small airways. This phantom study was performed to derive and test corrections to the measurements on the basis of consideration of partial volume averaging and tilt effects. MATERIALS AND METHODS A lung phantom with six polycarbonate tubes embedded in foam was scanned, and the cross-sectional dimensions of the tubes were determined using the full width at half maximum, zero crossing, and phase congruency edge detection methods. Equations were derived using the reported wall intensity to correct for partial volume averaging. Corrections for the overestimation of the wall thickness due to the tilt of the tube with respect to the CT z-axis were also derived. RESULTS All three methods (full width at half maximum, zero crossing, and phase congruency) overestimated the wall thickness of the small polycarbonate tubes. It was verified that two sources of error were partial volume averaging and tilt that was introduced when the phantom was positioned with tube axes at an angle to the CT z-axis. The corrections were applied to the measured tube wall dimensions and substantially reduced the deviation of the CT measurements from the true values. CONCLUSIONS Correcting for partial volume effects and airway tilt greatly increases the accuracy of simulated airway wall measurements in transverse CT images.
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Pyrgos G, Scichilone N, Togias A, Brown RH. Bronchodilation response to deep inspirations in asthma is dependent on airway distensibility and air trapping. J Appl Physiol (1985) 2010; 110:472-9. [PMID: 21071596 DOI: 10.1152/japplphysiol.00603.2010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In healthy individuals, deep inspirations (DIs) have a potent bronchodilatory ability against methacholine (MCh)-induced bronchoconstriction. This is variably attenuated in asthma. We hypothesized that inability to bronchodilate with DIs is related to reduced airway distensibility. We examined the relationship between DI-induced bronchodilation and airway distensibility in 15 asthmatic individuals with a wide range of baseline lung function [forced expired volume in 1 s (FEV(1)) = 60-99% predicted]. After abstaining from DIs for 20 min, subjects received a single-dose MCh challenge and then asked to perform DIs. The effectiveness of DIs was assessed by the ability of the subjects to improve FEV(1). The same subjects were studied by two sets of high-resolution CT scans, one at functional residual capacity (FRC) and one at total lung capacity (TLC). In each subject, the areas of 21-41 airways (0.8-6.8 mm diameter at FRC) were matched and measured, and airway distensibility (increase in airway diameter from FRC to TLC) was calculated. The bronchodilatory ability of DIs was significantly lower in individuals with FEV(1) <75% predicted than in those with FEV(1) ≥75% predicted (15 ± 11% vs. 46 ± 9%, P = 0.04) and strongly correlated with airway distensibility (r = 0.57, P = 0.03), but also with residual volume (RV)/TLC (r = -0.63, P = 0.01). In multiple regression, only RV/TLC was a significant determinant of DI-induced bronchodilation. These relationships were lost when the airways were examined after maximal bronchodilation with albuterol. Our data indicate that the loss of the bronchodilatory effect of DI in asthma is related to the ability to distend the airways with lung inflation, which is, in turn, related to the extent of air trapping and airway smooth muscle tone. These relationships only exist in the presence of airway tone, indicating that structural changes in the conducting airways visualized by high-resolution CT do not play a pivotal role.
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Affiliation(s)
- George Pyrgos
- Johns Hopkins Univ., 615 N. Wolfe St., Rm. E7614, Baltimore, MD 21205, USA
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Eberlein M, Permutt S, Brown RH, Brooker A, Chahla MF, Bolukbas S, Nathan SD, Pearse DB, Orens JB, Brower RG. Supranormal expiratory airflow after bilateral lung transplantation is associated with improved survival. Am J Respir Crit Care Med 2010; 183:79-87. [PMID: 20693376 DOI: 10.1164/rccm.201004-0593oc] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
RATIONALE flow volume loops (FVL) in some bilateral lung transplant (BLT) and heart-lung transplant (HLT) patients suggest variable extrathoracic obstruction in the absence of identifiable causes. These FVLs usually have supranormal expiratory and normal inspiratory flow rates (SUPRA pattern). OBJECTIVES characterize the relationship of the SUPRA pattern to predicted donor and recipient lung volumes, airway size, and survival. METHODS we performed a retrospective review of adult BLT/HLT patients. We defined the SUPRA FVL pattern as: (1) mid-vital capacity expiratory to inspiratory flow ratio (Ve50:Vi50) > 1.0, (2) absence of identifiable causes of extrathoracic obstruction, and (3) Ve50/FVC ≥ 1.5 s(-1). We calculated predicted total lung capacity (pTLC) ratio by dividing the donor pTLC by the recipient pTLC. We measured airway luminal areas on thoracic computer tomographic scans. We compared survival in patients with and without the SUPRA pattern. MEASUREMENTS AND MAIN RESULTS the SUPRA FVL pattern occurred in 56% of the 89 patients who qualified for the analysis. The pTLC ratio of SUPRA and non-SUPRA patients was 1.11 and 0.99, respectively (P = 0.004). A higher pTLC ratio was correlated with increased probability of the SUPRA pattern (P = 0.0072). Airway luminal areas were larger in SUPRA patients (P = 0.009). Survival was better in the SUPRA cohort (P = 0.009). CONCLUSIONS the SUPRA FVL pattern was frequent in BLT/HLT patients. High expiratory flows in SUPRA patients could result from increased lung elastic recoil or reduced airway resistance, both of which could be caused by the pTLC mismatch. Improved survival in the SUPRA cohort suggests potential therapeutic approaches to improve outcomes in BLT/HLT patients.
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Affiliation(s)
- Michael Eberlein
- M.D. Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument Street, 5th floor, Baltimore, MD 21205, USA.
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Brown RH, Kaczka DW, Mitzner W. Effect of parenchymal stiffness on canine airway size with lung inflation. PLoS One 2010; 5:e10332. [PMID: 20436667 PMCID: PMC2859932 DOI: 10.1371/journal.pone.0010332] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 02/25/2010] [Indexed: 11/18/2022] Open
Abstract
Although airway patency is partially maintained by parenchymal tethering, this structural support is often ignored in many discussions of asthma. However, agonists that induce smooth muscle contraction also stiffen the parenchyma, so such parenchymal stiffening may serve as a defense mechanism to prevent airway narrowing or closure. To quantify this effect, specifically how changes in parenchymal stiffness alter airway size at different levels of lung inflation, in the present study, we devised a method to separate the effect of parenchymal stiffening from that of direct airway narrowing. Six anesthetized dogs were studied under four conditions: baseline, after whole lung aerosol histamine challenge, after local airway histamine challenge, and after complete relaxation of the airways. In each of these conditions, we used High resolution Computed Tomography to measure airway size and lung volume at five different airway pressures (0, 12, 25, 32, and 45 cm H(2)O). Parenchymal stiffening had a protective effect on airway narrowing, a fact that may be important in the airway response to deep inspiration in asthma. When the parenchyma was stiffened by whole lung aerosol histamine challenge, at every lung volume above FRC, the airways were larger than when they were directly challenged with histamine to the same initial constriction. These results show for the first time that a stiff parenchyma per se minimizes the airway narrowing that occurs with histamine challenge at any lung volume. Thus in clinical asthma, it is not simply increased airway smooth muscle contraction, but perhaps a lack of homogeneous parenchymal stiffening that contributes to the symptomatic airway hyperresponsiveness.
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Affiliation(s)
- Robert H. Brown
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - David W. Kaczka
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Wayne Mitzner
- Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
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Abstract
Computed tomography has facilitated recognition that chronic obstructive pulmonary disease is not a single disease but encompasses several overlapping entities, including emphysema, bronchitis, and small airways disease. Quantitative computed tomography can effectively characterize and quantify the extent of emphysema, airway wall thickening, and air trapping related to small airways disease.
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Distribution of airway narrowing responses across generations and at branching points, assessed in vitro by anatomical optical coherence tomography. Respir Res 2010; 11:9. [PMID: 20092657 PMCID: PMC2824705 DOI: 10.1186/1465-9921-11-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 01/22/2010] [Indexed: 11/20/2022] Open
Abstract
Background Previous histological and imaging studies have shown the presence of variability in the degree of bronchoconstriction of airways sampled at different locations in the lung (i.e., heterogeneity). Heterogeneity can occur at different airway generations and at branching points in the bronchial tree. Whilst heterogeneity has been detected by previous experimental approaches, its spatial relationship either within or between airways is unknown. Methods In this study, distribution of airway narrowing responses across a portion of the porcine bronchial tree was determined in vitro. The portion comprised contiguous airways spanning bronchial generations (#3-11), including the associated side branches. We used a recent optical imaging technique, anatomical optical coherence tomography, to image the bronchial tree in three dimensions. Bronchoconstriction was produced by carbachol administered to either the adventitial or luminal surface of the airway. Luminal cross sectional area was measured before and at different time points after constriction to carbachol and airway narrowing calculated from the percent decrease in luminal cross sectional area. Results When administered to the adventitial surface, the degree of airway narrowing was progressively increased from proximal to distal generations (r = 0.80 to 0.98, P < 0.05 to 0.001). This 'serial heterogeneity' was also apparent when carbachol was administered via the lumen, though it was less pronounced. In contrast, airway narrowing was not different at side branches, and was uniform both in the parent and daughter airways. Conclusions Our findings demonstrate that the bronchial tree expresses intrinsic serial heterogeneity, such that narrowing increases from proximal to distal airways, a relationship that is influenced by the route of drug administration but not by structural variations accompanying branching sites.
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Górska K, Krenke R, Kosciuch J, Korczynski P, Zukowska M, Domagala-Kulawik J, Maskey-Warzechowska M, Chazan R. Relationship between airway inflammation and remodeling in patients with asthma and chronic obstructive pulmonary disease. Eur J Med Res 2009; 14 Suppl 4:90-6. [PMID: 20156734 PMCID: PMC3521369 DOI: 10.1186/2047-783x-14-s4-90] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED Despite a number of important differences in the pathogenesis, course and prognosis of asthma and chronic obstructive pulmonary disease (COPD), these two entities also have common features with airway inflammation being one of them. Airway remodeling is a characteristic feature of asthma, but data on the bronchial wall thickening in COPD patients are still scarce. AIM To assess the relation between the inflammatory cell count in the bronchoalveolar lavage fluid (BALF) and thickness of bronchial walls assessed by high resolution computed tomography (HRCT) in asthma and COPD patients. MATERIAL AND METHODS The study was conducted in 9 patients with mild-to-moderate asthma (M/F 4/5, mean age 35 +/- 10 years) and 11 patients with mild-to-moderate COPD (M/F 7/4, mean age 57 +/- 9 years). In all subjects lung function tests and HRCT scanning of the chest were performed. External (D) and internal (L) diameters of the airways were assessed at five selected lung levels. The lumen area (A(L)), wall area (WA), wall thickness (WT) and bronchial wall thickness (WT/D ratio) were calculated. Eight patients with asthma and 8 patients with COPD underwent fiberoptic bronchoscopy and bronchoalveolar lavage (BAL). Total and differential cell counts were assessed in the BAL fluid. RESULTS Mean FEV(1)% pred was 80 +/- 19%, and 73 +/- 20% in asthma and COPD patients, respectively (NS). No significant differences in the total and differential cell counts in BALF were found in patients with asthma and COPD. There were no significant differences in the airway diameter or airway wall thickness. The mean inner airway diameter was 1.4 +/- 0.3 and 1.2 +/- 0.3 mm and the mean lumen area was 1.8 +/- 0.7 and 1.6 +/- 0.7 mm(2) in asthma and COPD, respectively (NS). Negative correlations between the eosinophil count in BALF and inner airway diameter (r=-0.7, P<0.05) and lumen area (r=-0.7, P<0.05) were found in asthmatics. There was no significant relationship between the BALF cell count and airway wall thickness in COPD patients. - CONCLUSIONS In mild-to-moderate asthma and COPD the airway diameter and thickness are similar. In asthmatics, the airway diameter might be associated with eosinophil count in BAL fluid.
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Affiliation(s)
- K Górska
- Department of Internal Medicine, Pneumology and Allergology, Medical University of Warsaw, Warsaw, Poland.
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Groeben H, Brown RH, Kaba S, Mitzner W. DIFFERENT MECHANISMS OF ATELECTASIS FORMATION REQUIRE DIFFERENT TREATMENT STRATEGIES. Exp Lung Res 2009; 34:115-24. [DOI: 10.1080/01902140701884356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Washko GR, Dransfield MT, Estépar RSJ, Diaz A, Matsuoka S, Yamashiro T, Hatabu H, Silverman EK, Bailey WC, Reilly JJ. Airway wall attenuation: a biomarker of airway disease in subjects with COPD. J Appl Physiol (1985) 2009; 107:185-91. [PMID: 19407254 DOI: 10.1152/japplphysiol.00216.2009] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The computed tomographic (CT) densities of imaged structures are a function of the CT scanning protocol, the structure size, and the structure density. For objects that are of a dimension similar to the scanner point spread function, CT will underestimate true structure density. Prior investigation suggests that this process, termed contrast reduction, could be used to estimate the strength of thin structures, such as cortical bone. In this investigation, we endeavored to exploit this process to provide a CT-based measure of airway disease that can assess changes in airway wall thickening and density that may be associated with the mural remodeling process in subjects with chronic obstructive pulmonary disease (COPD). An initial computer-based study using a range of simulated airway wall sizes and densities suggested that CT measures of airway wall attenuation could detect changes in both wall thickness and structure density. A second phantom-based study was performed using a series of polycarbonate tubes of known density. The results of this again demonstrated the process of contrast reduction and further validated the computer-based simulation. Finally, measures of airway wall attenuation, wall thickness, and wall area (WA) divided by total cross-sectional area, WA percent (WA%), were performed in a cohort of 224 subjects with COPD and correlated with spirometric measures of lung function. The results of this analysis demonstrated that wall attenuation is comparable to WA% in predicting lung function on univariate correlation and remain as a statistically significant correlate to the percent forced expiratory volume in 1 s predicted when adjusted for measures of both emphysema and WA%. These latter findings suggest that the quantitative assessment of airway wall attenuation may offer complementary information to WA% in characterizing airway disease in subjects with COPD.
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Affiliation(s)
- George R Washko
- Pulmonary and Critical Care Division, Dept. of Medicine, Brigham and Women's Hospital, 75 Francis St., Boston, MA 02115, USA.
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Kim WJ, Oh YM, Sung J, Lee YK, Seo JB, Kim N, Kim TH, Huh JW, Lee JH, Kim EK, Lee JH, Lee SM, Lee S, Lim SY, Shin TR, Yoon HI, Kwon SY, Lee SD. CT scanning-based phenotypes vary with ADRB2 polymorphisms in chronic obstructive pulmonary disease. Respir Med 2009; 103:98-103. [DOI: 10.1016/j.rmed.2008.07.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 07/21/2008] [Accepted: 07/25/2008] [Indexed: 11/28/2022]
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Cohen J, Douma WR, van Ooijen PMA, Willems TP, Dicken V, Kuhnigk JM, ten Hacken NHT, Postma DS, Oudkerk M. Localization and quantification of regional and segmental air trapping in asthma. J Comput Assist Tomogr 2008; 32:562-9. [PMID: 18664844 DOI: 10.1097/rct.0b013e31815f2bb0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE To assess the feasibility of volumetric and densitometric software to localize and quantify signs of regional air trapping after methacholine bronchoprovocations in asthma. METHODS Eight atopic subjects with mild-to-moderate asthma using short-acting beta2-agonists only, with hyperresponsiveness to methacholine, were evaluated. Low-dose baseline expiratory 16-slice multidetector computed tomography scans before and after a methacholine bronchoprovocation were acquired. MeVisPULMO3D software (Bremen, Germany) was applied to the scans, providing quantitative information on volume and density measures of the total lung and each lobe. RESULTS After methacholine, the expiratory scan showed a median (interquartile range) increase in volume of 534 mL (357-1279 mL), a decrease in lung density (mean and 15th percentile) of 52 Hounsfield Units (HU) (116-39 HU) and 34 HU (78-25 HU), respectively, and an increase in percentage low attenuation areas of 3% (2%-6%) for the total lung, with similar patterns in individual lung lobes. The right and left lower lung lobes showed the largest increases in air trapping, 211 mL (117-363 mL) and 229 mL (155-315 mL), respectively, versus a volume increase of 70 mL (20-249 mL), 26 mL (-16-92 mL), and 91 mL (-28-241 mL) for the right upper, middle, and left upper lobes, respectively. Volume changes in the lower lobes were associated with baseline forced expiratory flow between 25% and 75% of forced vital capacity, whereas low attenuation areas changes in the lower lobes were not. CONCLUSIONS This study suggests that multidetector computed tomography scans are able to localize and quantify regional air trapping in asthma after methacholine bronchoprovocations. Volumetric measurements of the lobes as compared to densitometric measurements are superior in detecting local air trapping in gravity-dependent areas of the lung.
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Affiliation(s)
- Judith Cohen
- Department of Pulmonology, University Medical Center Groningen, University of Groningen, the Netherlands
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MDCT assessment of airway wall thickness in COPD patients using a new method: correlations with pulmonary function tests. Eur Radiol 2008; 18:2731-8. [PMID: 18641993 DOI: 10.1007/s00330-008-1089-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 05/12/2008] [Accepted: 05/24/2008] [Indexed: 12/21/2022]
Abstract
Quantitative assessment of airway-wall dimensions by computed tomography (CT) has proven to be a marker of airway-wall remodelling in chronic obstructive pulmonary disease (COPD) patients. The objective was to correlate the wall thickness of large and small airways with functional parameters of airflow obstruction in COPD patients on multi-detector (MD) CT images using a new quantification procedure from a three-dimensional (3D) approach of the bronchial tree. In 31 patients (smokers/COPD, non-smokers/controls), we quantitatively assessed contiguous MDCT cross-sections reconstructed orthogonally along the airway axis, taking the point-spread function into account to circumvent over-estimation. Wall thickness and wall percentage were measured and the per-patient mean/median correlated with FEV1 and FEV1%. A median of 619 orthogonal airway locations was assessed per patient. Mean wall percentage/mean wall thickness/median wall thickness in non-smokers (29.6%/0.69 mm/0.37 mm) was significantly different from the COPD group (38.9%/0.83 mm/0.54 mm). Correlation coefficients (r) between FEV1 or FEV1% predicted and intra-individual means of the wall percentage were -0.569 and -0.560, respectively, with p < 0.001. Depending on the parameter, they were increased for airways of 4 mm and smaller in total diameter, being -0.621 (FEV1) and -0.537 (FEV1%) with p < 0.002. The wall thickness was significantly higher in smokers than in non-smokers. In COPD patients, the wall thickness measured as a mean for a given patient correlated with the values of FEV1 and FEV1% predicted. Correlation with FEV1 was higher when only small airways were considered.
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Tzeng YS, Hoffman E, Cook-Granroth J, Gereige J, Mansour J, Washko G, Cho M, Stepp E, Lutchen K, Albert M. Investigation of hyperpolarized 3He magnetic resonance imaging utility in examining human airway diameter behavior in asthma through comparison with high-resolution computed tomography. Acad Radiol 2008; 15:799-808. [PMID: 18486015 DOI: 10.1016/j.acra.2008.02.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 01/16/2008] [Accepted: 02/11/2008] [Indexed: 11/17/2022]
Abstract
RATIONALE AND OBJECTIVES Application of a previously developed model-based algorithm on hyperpolarized (HP) (3)He magnetic resonance (MR) dynamic projection images of phantoms was extended to investigate the utility of HP (3)He MR imaging (MRI) in quantifying airway caliber changes associated with asthma. MATERIALS AND METHODS Airways of seven volunteers were imaged and measured using HP (3)He MRI and multidetector-row computed tomography (MDCT) before and after a methacholine (MCh) challenge. MDCT data were obtained at functional residual capacity and 1 L above functional residual capacity. RESULTS Comparison of the resultant data showed that HP (3)He MRI did not match MDCT in measuring the ratios of airway calibers before and after the MCh challenge in 37% to 43% of the airways from the first six generations at the two lung volumes tested. However, MDCT did yield the observation that 49% to 69% of these airways displayed bronchodilation following MCh challenge. CONCLUSION The current implementation of HP (3)He MRI did not match the MCh-induced postchallenge-to-prechallenge airway caliber ratios as measured with MDCT. Elevated parenchymal tethering due to bronchoconstriction-induced hyperinflation was proposed as a possible explanation for this airway dilation.
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Affiliation(s)
- Yang-Sheng Tzeng
- Department of Radiology, Brigham & Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA.
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Kim N, Seo JB, Song KS, Chae EJ, Kang SH. Semi-automatic measurement of the airway dimension by computed tomography using the full-width-half-maximum method: a study on the measurement accuracy according to the CT parameters and size of the airway. Korean J Radiol 2008; 9:226-35. [PMID: 18525225 PMCID: PMC2627250 DOI: 10.3348/kjr.2008.9.3.226] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Accepted: 11/16/2007] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To assess the influence of variable factors such as the size of the airway and the CT imaging parameters such as the reconstruction kernel, field-of-view (FOV), and slice thickness on the automatic measurement of airway dimension. MATERIALS AND METHODS An airway phantom was fabricated that contained eleven poly-acryl tubes of various lumen diameters and wall thicknesses. The measured density of the poly-acryl wall was 150 HU, and the measured density of the airspace filled with polyurethane foam was -900 HU. CT images were obtained using a 16-MDCT (multidetector CT) scanner and were reconstructed with various reconstruction kernels, thicknesses and FOV. The luminal radius and wall thickness were measured using in-house software based on the full-width-half-maximum method. The measured values as determined by CT and the actual dimensions of the tubes were compared. RESULTS Measurements were most accurate on images reconstructed with use of a standard kernel (mean error: -0.03 +/- 0.21 mm for wall thickness and -0.12 +/- 0.11 mm for the luminal radius). There was no significant difference in accuracy among images with the use of variable slice thicknesses or a variable FOV. Below a 1-mm threshold, the measurement failed to represent the change of the real dimensions. CONCLUSION Measurement accuracy was strongly influenced by the specific reconstruction kernel utilized. For accurate measurement, standardization of the imaging protocol and selection of the appropriate anatomic level are essential.
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Affiliation(s)
- Namkug Kim
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea
- Department of Industrial Engineering, Seoul National University, Seoul 138-736, Korea
| | - Joon Beom Seo
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea
| | - Koun-Sik Song
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea
| | - Eun Jin Chae
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea
| | - Suk-Ho Kang
- Department of Industrial Engineering, Seoul National University, Seoul 138-736, Korea
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Quantitative assessment of emphysema, air trapping, and airway thickening on computed tomography. Lung 2008; 186:157-165. [PMID: 18351420 DOI: 10.1007/s00408-008-9071-0] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Accepted: 01/08/2008] [Indexed: 10/22/2022]
Abstract
The severity of chronic obstructive pulmonary disease (COPD) is evaluated not only by airflow limitation but also by factors such as exercise capacity and body mass index. Recent advances in CT technology suggest that it might be a useful tool for evaluating the severity of the disease components of COPD. The aim of this study is to evaluate the correlation between the parameters measured on volumetric CT, including the extent of emphysema, air trapping, and airway thickening, and clinical parameters. CT scans were performed in 34 patients with COPD at full inspiration and expiration. We used in-house software to measure CT parameters, including volume fraction of emphysema (V(950)), mean lung density (MLD), CT air trapping index (CT ATI), segmental bronchial wall area (WA), lumen area (LA), and wall area percent (WA%). We found that the CT parameters were correlated with the pulmonary function test (PFT) results, body mass index (BMI), the modified Medical Research Council Dyspnea scale (MMRC scale), the six-minute-walk distance (6MWD), and the BODE index. V(950 insp) correlated to the BMI, FEV(1), 6MWD, and the BODE index. The CT ATI correlated with the physiologic ATI (VC-FVC) (R=0.345, p=0.045) and the MMRC scale (R=0.532, p=0.001). There was a positive correlation between the WA% and the BMI (R=0.563, p<0.001). MLD(exp) showed the strongest correlation with the BODE index (R= -0.756, p<0.001). We conclude that the severity of emphysema and air trapping measured on CT correlated with the PFT parameters 6MWD and BMI.
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Abstract
Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled multi-detector row CT allow for quantification of presence and distribution of parenchymal and airway pathology; xenon gas can be employed to assess regional ventilation of the lungs, and rapid bolus injections of iodinated contrast agent can provide a quantitative measure of regional parenchymal perfusion. Advances in MRI of the lung include gadolinium-enhanced perfusion imaging and hyperpolarized gas imaging, which allow functional assessment, including ventilation/perfusion, microscopic air space measurements, and gas flow and transport dynamics.
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Affiliation(s)
- Edwin J R van Beek
- Department of Radiology, Carver College of Medicine, University of Iowa, C-751 GH, 200 Hawkins Drive, Iowa City, IA 52242-1077, USA.
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Brown RH, Kaczka DW, Fallano K, Chen S, Mitzner W. Temporal variability in the responses of individual canine airways to methacholine. J Appl Physiol (1985) 2008; 104:1381-6. [PMID: 18309091 DOI: 10.1152/japplphysiol.01348.2007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous work showed that individual airway size, before any spasmogen, varied widely in the same animals on different days. The effect of this variable baseline size on the airway response to a subsequent challenge is unknown. The present study examined how the variability in individual airway baseline size in dogs was related to that after methacholine challenge on 4 different days using high-resolution computed tomography scans. Dogs were anesthetized and ventilated, and on 4 separate days randomly varying between 1 and 8 wk apart, baseline scans were acquired, followed by a continuous intravenous infusion of methacholine at three rates in increasing order (17, 67, and 200 microg/min). As the measure of variability, we used the coefficient of variation (CV) of the four airway luminal measurements of each airway at baseline and at each dose of methacholine. For most airways, there was wide variability both between and within dogs in the response to a given dose of methacholine (CV = 33-38%). Airways with any level of methacholine stimulation had greater variability than those at baseline. The airway variability was greatest at the lowest dose of methacholine administered but was elevated at all the doses. In conclusion, there was substantial day-to-day variability in baseline airway size. Most importantly, the same dose of methacholine to the same individual airway showed even greater variability than that at baseline. If we consider that increased heterogeneity may potentiate clinical symptoms, then airway response variability may play an important role in the manifestation of airway disease.
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Affiliation(s)
- Robert H Brown
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA.
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Tzeng YS, Hoffman E, Cook-Granroth J, Maurer R, Shah N, Mansour J, Tschirren J, Albert M. Comparison of airway diameter measurements from an anthropomorphic airway tree phantom using hyperpolarized 3He MRI and high-resolution computed tomography. Magn Reson Med 2007; 58:636-42. [PMID: 17763351 PMCID: PMC2943874 DOI: 10.1002/mrm.21285] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An anthropomorphic airway tree phantom was imaged with both hyperpolarized (HP) 3He MRI using a dynamic projection scan and computed tomography (CT). Airway diameter measurements from the HP 3He MR images obtained using a newly developed model-based algorithm were compared against their corresponding CT values quantified with a well-established method. Of the 45 airway segments that could be evaluated with CT, only 14 airway segments (31%) could be evaluated using HP 3He MRI. No airway segments smaller than approximately 4 mm in diameter and distal to the fourth generation were adequate for analysis in MRI. For the 14 airway segments measured, only two airway segments yielded a non-equivalent comparison between the two imaging modalities, while eight more had inconclusive comparison results, leaving only four airway segments (29%) that satisfied the designed equivalence criteria. Some of the potential problems in airway diameter quantification described in the formulation of the model-based algorithm were observed in this study. These results suggest that dynamic projection HP 3He MRI may have limited utility for measuring airway segment diameters, particularly those of the central airways.
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Affiliation(s)
- Yang-Sheng Tzeng
- Department of Radiology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
| | - Eric Hoffman
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | | | - Rie Maurer
- Department of Gastroenterology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Niral Shah
- Department of Radiology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
| | - Joey Mansour
- Department of Radiology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Juerg Tschirren
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | - Mitchell Albert
- Department of Radiology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Correspondence to: Mitchell Albert, Department of Radiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655.
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Cheng Y, Wang S, Yamazaki T, Zhao J, Nakajima Y, Tamura S. Hip cartilage thickness measurement accuracy improvement. Comput Med Imaging Graph 2007; 31:643-55. [PMID: 17904821 DOI: 10.1016/j.compmedimag.2007.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 07/27/2007] [Accepted: 08/02/2007] [Indexed: 11/30/2022]
Abstract
Accurate measurement of the distance separating two adjacent sheet structures, such as femoral cartilage and acetabular cartilage in the hip joint is important in evaluation of osteoarthritis. A new method, insensitive to the influence of adjacent sheet structures, was developed to improve the accuracy of hip cartilage thickness measurement. A theoretical simulation for investigating the influence of adjacent sheet structures on the accuracy of cartilage thickness measurement in MR images was performed. The thickness is defined as the distance between zero-crossings of the second directional derivatives along the sheet surface normal direction. The simulation measurement showed considerable underestimation in thickness measurement occurred due to the influence of the adjacent sheet. A new method based on a model of the MR imaging process to eliminate the influence of adjacent sheet structure was developed and tested using phantoms and two cadaveric human hip joint MR scans. The new method reduced the influence of the adjacent sheet structure was more accurate than the conventional method for measuring hip cartilage thickness.
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Affiliation(s)
- Yuanzhi Cheng
- School of Computer Science and Technology, Harbin Institute of Technology in Weihai, China.
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Brown R, Wizeman W, Danek C, Mitzner W. Effect of Bronchial Thermoplasty on Airway Closure. CLINICAL MEDICINE. CIRCULATORY, RESPIRATORY AND PULMONARY MEDICINE 2007; 1:1-6. [PMID: 19865588 DOI: 10.4137/ccrpm.s365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND: Bronchial Thermoplasty, a procedure that applies thermal energy to the airway wall has been shown to impair the ability of airway to contract in response to methacholine chloride (Mch). The technique has been advocated as an alternative treatment for asthma that may permanently limit airway narrowing. In previous experimental studies in dogs and humans, it was shown that those airways treated with bronchial thermoplasty had significant impairment of Mch responsiveness. METHODS: In the present study, we investigated the ability of canine airways to close completely with very high concentrations of Mch after bronchial thermoplasty. Bronchial thermoplasty was performed on dogs using the Alair System, comprising a low power RF controller and a basket catheter with four electrodes. A local atomization of Mch agonist was delivered directly to the epithelium of the same airway locations with repeated challenges. Airway size was measured with computed tomography, and closure was considered to occur in any airway where the lumen fell below the resolution of the scanner (< 1 mm). RESULTS: Our results show that, while treated airways still have the capacity to close at very high doses of Mch, this ability is seriously impaired after treatment, requiring much higher doses. CONCLUSIONS: Bronchial thermoplasty as currently applied seems to simply shift the entire dose response curve toward increasing airway size. Thus, this procedure simply serves to minimize the ability of airways to narrow under any level of stimulation.
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Kleinsasser A, Olfert IM, Loeckinger A, Prisk GK, Hopkins SR, Wagner PD. Tidal volume dependency of gas exchange in bronchoconstricted pig lungs. J Appl Physiol (1985) 2007; 103:148-55. [PMID: 17395763 DOI: 10.1152/japplphysiol.00451.2006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Independent of airway pressure, pulmonary resistance is known to fall with increasing tidal volumes, traditionally thought to result from radial traction on the airways. R. C. Anafi and T. A. Wilson ( J Appl Physiol 91: 1185–1192, 2001) recently presented a model of a single terminal airway that explains the tidal volume-associated fall in resistance with an additional mechanism pertinent to narrow airways: a stable, nearly closed airway that is challenged with an increase in tidal volume “pops open” to become a stable, well-opened airway, and thus resistance drops suddenly. To test this model in vivo, the effects of high (24 ml/kg) and low (9 ml/kg) tidal volume in bronchoconstricted lungs were assessed using 1) the multiple inert gas elimination technique (MIGET) and 2) a 15-breath multiple breath inert gas washout (MBW) technique in anesthetized pigs. With high tidal volume, ventilation/perfusion (V̇a/Q̇) mismatch was reduced (log SD Q̇ from 1.30 ± 0.11 to 1.09 ± 0.12, P < 0.05), and blood flow to lung units with V̇a/Q̇ ratios < 0.1 was significantly reduced (37 ± 4% of cardiac output to 7 ± 4%, P < 0.05). Dynamic compliance was twice as high during high-tidal-volume ventilation ( P = 0.002). MBW analysis revealed that, while heterogeneity of ventilation during bronchoconstriction was not significantly different between either low or high tidal volume (log SD V̇mbw = 1.39 ± 0.09 and 1.34 ± 0.02, respectively), preinspiratory lung volume (PILV) decreased by 42% with low-tidal-volume ventilation ( P < 0.05), whereas it did not change with high-tidal-volume ventilation. The higher PILV during high tidal volume is also consistent with Anafi and Wilson's model. In summary, the outcomes from MIGET, and to some extent the MBW, in our anesthetized and mechanically ventilated pigs are consistent with a bistable terminal airway model as proposed by Anafi and Wilson. However, our data do not allow exclusion of other mechanisms that may lead to improved ventilatory distribution when tidal volume is increased.
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Affiliation(s)
- Axel Kleinsasser
- Department of Medicine, Division of Physiology, University of California-San Diego, La Jolla, California 92093-0623, USA
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Chang HYS, Togias A, Brown RH. The effects of systemic lidocaine on airway tone and pulmonary function in asthmatic subjects. Anesth Analg 2007; 104:1109-15, tables of contents. [PMID: 17456660 DOI: 10.1213/01.ane.0000260638.57139.87] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND To prevent reflex-induced bronchoconstriction in patients with asthma, local anesthetics are commonly administered by aerosol or IV as adjunct medication. Lidocaine attenuates responsiveness to a neurally active stimulus that increases tone, but there is scant information about the effect of lidocaine on baseline airway tone. Therefore we examined the effects of IV lidocaine on baseline airway tone in asthmatic subjects. METHODS Small, medium, and large airways (2-5, 5-8, >8 mm diameter) were analyzed by computed tomography in 15 asthmatic volunteers under baseline conditions and during infusion of lidocaine. Changes in luminal airway diameter and wall thickness from baseline to during lidocaine infusion, and the change in pulmonary function induced by lidocaine, were analyzed. RESULTS Lidocaine caused a significant decrease in the forced expiratory volume in 1 s pulmonary function measure (7 +/- 2%, P = 0.006). There was also a small but significant decrease in the airway luminal diameter at total lung capacity during lidocaine infusion compared to baseline (-3 +/- 0.5%, P < 0.001). Moreover, there was a significant correlation between the change in forced expiratory volume in 1 s and the change in airway luminal diameter at total lung capacity (r2 = 0.47, P = 0.01). CONCLUSION Lidocaine, which reduces airway responsiveness to drugs that cause bronchospasm through sensory nerve activation, did not reduce baseline airway tone. Instead, even when administered IV, lidocaine significantly increased airway tone and caused airway narrowing. Therefore, while the administration of lidocaine can prevent intubation-induced bronchospasm, the airways should be constantly monitored by auscultation even during IV lidocaine administration.
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Affiliation(s)
- Herng-Yu Sucie Chang
- Department of Environmental Health Sciences, The Johns Hopkins University, Baltimore, Maryland 21205, USA
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