RATIONALE: Bronchiolitis obliterans syndrome (BOS) is a late, non-infectious pulmonary complication following hematopoietic stem cell transplantation (HSCT). There is minimal data published on quantitative radiologic characterization of airway remodeling in these subjects.
OBJECTIVES: To examine quantitative measurements of airway morphology and their correlation with lung function in a cohort of patients who underwent HSCT and developed BOS.
METHODS: All adult patients who underwent allogeneic HSCT at the Dana-Farber Cancer Institute/Brigham and Women's Hospital (n = 1854) between January 1st 2000 and June 30th 2010 were screened for the development of BOS. Clinically acquired high resolution CT (HRCT) scans of the chest were collected. For each subjects discrete measures of airway wall area were performed and the square root of wall area of a 10-mm luminal perimeter (Pi10) was calculated.
MEASUREMENTS AND MAIN RESULTS: We identified 88 cases of BOS, and 37 of these patients had available HRCT. On CT scans obtained after BOS diagnosis, the Pi10 decreased (consistent with airway dilation) as compared with pre-BOS values (p < 0.001). After HSCT the Pi10 correlated with FEV(1)% predicted (r = 0.636, p < 0.0001), and RV/TLC% predicted (r = -0.736, p < 0.0001), even after adjusting for age, sex and total lung capacity (p < 0.0001 for both).
CONCLUSIONS: On HRCT scan BOS is characterized by central airway dilation, the degree of which is correlated to decrements in lung function. This is opposite of what has been previously demonstrated in COPD and asthma that quantitative measure of proximal airway wall thickening directly correlate with pulmonary function. Our data suggests that the pathologic process affecting the central airways is different from the pathology observed in the distal airways. Further work is needed to determine if such change can be used as a sensitive and specific tool for the future diagnosis and staging of BOS.
BACKGROUND: Lung cancer is the leading cause of cancer death and a major public health challenge across the entire world. Computed tomography (CT) imaging of the lung is a rapidly improving medical imaging technique. Spiral CT has been reported to not only improve the early detection of lung cancer in screening high-risk tobacco-exposed populations but also to assist in the clinical assessment of new agents for therapy in lung cancer.
METHODS: The Prevent Cancer Foundation has sponsored a series of workshops to accelerate progress in using quantitative imaging to advance lung cancer research progress, of which this report summarizes the Ninth Workshop. The defining strategy of this forum to support innovation in quantitative research for early lung cancer management was to enable software validations by assembling collections of high-quality images for which long-term clinical follow-up is known. An additional approach was to define a process for high-quality and economical national implementation of lung cancer screening. Representatives from the Quantitative Imaging Biomarker Alliance, the International Association for the Study of Lung Cancer, the Lung Cancer Alliance, and other organizations outlined their efforts in this regard. A major opportunity exists to advance the dialogue on the use of quantitative imaging tools to cross-fertilize and accelerate image-processing research across lung cancer and chronic obstructive pulmonary disease (COPD).
CONCLUSION: The use of high-resolution CT imaging provides a window into a much earlier stage of COPD as well as coronary artery disease, both being tobacco-induced diseases. Progress in this area was reviewed and opportunities for enhanced collaborative progress defined. Key sessions reviewed emerging developments with imaging technology and the infrastructure to support the storage and distribution of these high-content modalities. Cooperation among diverse collaborators is essential to enable the rapid organic evolution of this field, so that improved outcomes with lung cancer, artery disease, and COPD can be obtained.
BACKGROUND: CT scanning is increasingly used to characterize COPD. Although it is possible to obtain CT scan-measured lung lobe volumes, normal ranges remain unknown. Using COPDGene data, we developed reference equations for lobar volumes at maximal inflation (total lung capacity [TLC]) and relaxed exhalation (approximating functional residual capacity [FRC]).
METHODS: Linear regression was used to develop race-specific (non-Hispanic white [NHW], African American) reference equations for lobar volumes. Covariates included height and sex. Models were developed in a derivation cohort of 469 subjects with normal pulmonary function and validated in 546 similar subjects. These cohorts were combined to produce final prediction equations, which were applied to 2,191 subjects with old GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage II to IV COPD.
RESULTS: In the derivation cohort, women had smaller lobar volumes than men. Height positively correlated with lobar volumes. Adjusting for height, NHWs had larger total lung and lobar volumes at TLC than African Americans; at FRC, NHWs only had larger lower lobes. Age and weight had no effect on lobar volumes at TLC but had small effects at FRC. In subjects with COPD at TLC, upper lobes exceeded 100% of predicted values in GOLD II disease; lower lobes were only inflated to this degree in subjects with GOLD IV disease. At FRC, gas trapping was severe irrespective of disease severity and appeared uniform across the lobes.
CONCLUSIONS: Reference equations for lobar volumes may be useful in assessing regional lung dysfunction and how it changes in response to pharmacologic therapies and surgical or endoscopic lung volume reduction.
BACKGROUND: Natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy (MED) through the esophagus has proved to be feasible in the animal model. However, injury of the adjacent pleura and pneumothorax has been reported as a frequent adverse event when using a blind access.
OBJECTIVE: To assess the utility and safety of a CT-based image registration system (IRS) for navigation in the mediastinum.
DESIGN: Prospective, randomized, controlled trial in 30 Yorkshire pigs. Thirty-minute MEDs were performed: 15 MEDs were performed with IRS guidance (MED-IRS), and 15 MEDs were performed with a blind access.
SETTING: Animal research laboratory.
INTERVENTIONS: In both groups, the mediastinum was accessed through a 10-cm submucosal tunnel in the esophageal wall. Timed exploration was performed with identification of 8 mediastinal structures.
MAIN OUTCOME MEASUREMENTS: Technical feasibility, adverse events, and the number of mediastinal structures identified.
RESULTS: Thirty animals weighing 31.5 ± 3.5 kg were included in this study. MED was not possible in 2 animals in the "MED with blind access" group but was possible in all MEDs performed with IRS. The mean number of identified organs was slightly higher in "with IRS-MED" (6.13 ± 1.3) than with MED with blind access (4.7 ± 2.3; P = .066). Moreover, the right atrium and vena cava were identified in more cases with IRS-MED than in MED with blind access (13 vs 3 and 15 vs 11, P = .000 and P = .03, respectively). There were 3 (23%) adverse events with IRS-MED and 4 (27%) with "MED with blind access" (P = not significant), with pneumothorax being the most frequent (2 and 3, respectively).
LIMITATIONS: Nonsurvival animal study.
CONCLUSIONS: This study demonstrates that the IRS system appears feasible in natural orifice transluminal endoscopic surgery MED and suggests that IRS guidance might be useful for selected procedures.
OBJECTIVES: We aimed to explore physiological responses to the six-minute walk test (6MWT) and assess computed tomographic (CT) features of the lungs and thigh muscle in order to determine contributors to dyspnea intensity and exercise limitation in dyspneic and non-dyspneic subjects with GOLD-1 COPD and controls.
METHODS: We compared Borg dyspnea ratings, ventilatory responses to 6MWT, and CT-measures of emphysema, airway lumen caliber, and cross-sectional area of the thigh muscle (RTMCT-CSA) in 19 dyspneic, 22 non-dyspneic, and 30 control subjects.
RESULTS: Dyspneic subjects walked less and experienced greater exertional breathlessness than non-dyspneic (105 m less and 2.4 Borg points more, respectively) and control subjects (94 m less and 2.6 Borg points more, respectively (P < 005 for all comparisons). At rest, dyspneic subjects had significant greater expiratory airflow obstruction, air trapping, ventilation/perfusion mismatch, burden of emphysema, narrower airway lumen, and lower RTMCT-CSA than comparison subjects. During walking dyspneic subjects had a decreased inspiratory capacity (IC) along with high ventilatory demand. Dyspneic subjects exhibited higher end-exercise tidal expiratory flow limitation and oxygen saturation drop than comparison subjects. In regression analysis, dyspnea intensity was best explained by ΔIC and forced expiratory volume in 1 s %predicted. RTMCT-CSA and ΔIC were independent determinants of distance walked.
CONCLUSIONS: Among subjects with mild COPD, those with daily-life dyspnea have worse exercise outcomes; distinct lung and thigh muscle morphologic features; and different pulmonary physiologic characteristics at rest and exercise. ΔIC was the main contributor to dyspnea intensity and ΔIC and thigh muscle wasting were determinants of exercise capacity.
BACKGROUND: In CT scans of smokers with COPD, the subsegmental airway wall area percent (WA%) is greater and more strongly correlated with FEV1 % predicted than WA% obtained in the segmental airways. Because emphysema is linked to loss of airway tethering and may limit airway expansion, increases in WA% may be related to emphysema and not solely to remodeling. We aimed to first determine whether the stronger association of subsegmental vs segmental WA% with FEV1 % predicted is mitigated by emphysema and, second, to assess the relationships among emphysema, WA%, and total bronchial area (TBA).
METHODS: We analyzed CT scan segmental and subsegmental WA% (WA% = 100 × wall area/TBA) of six bronchial paths and corresponding lobar emphysema, lung function, and clinical data in 983 smokers with COPD.
RESULTS: Compared with segmental WA%, the subsegmental WA% had a greater effect on FEV1% predicted (-0.8% to -1.7% vs -1.9% to -2.6% per 1-unit increase in WA%, respectively; P < .05 for most bronchial paths). After adjusting for emphysema, the association between subsegmental WA% and FEV1 % predicted was weakened in two bronchial paths. Increases in WA% between bronchial segments correlated directly with emphysema in all bronchial paths (P < .05). In multivariate regression models, emphysema was directly related to subsegmental WA% in most bronchial paths and inversely related to subsegmental TBA in all bronchial paths.
CONCLUSION: The greater effect of subsegmental WA% on airflow obstruction is mitigated by emphysema. Part of the emphysema effect might be due to loss of airway tethering, leading to a reduction in TBA and an increase in WA%.
Said MA, Johnson HL, Nonyane BAS, Deloria-Knoll M, O'Brien KL, Andreo F, Beovic B, Blanco S, Boersma WG, Boulware DR, Butler JC, Carratalà J, Chang F-Y, Charles PGP, Diaz AA, Domínguez J, Ehara N, Endeman H, Falcó V, Falguera M, Fukushima K, Garcia-Vidal C, Genne D, Guchev IA, Gutierrez F, Hernes SS, Hoepelman AIM, Hohenthal U, Johansson N, Kolek V, Kozlov RS, Lauderdale T-L, Mareković I, Masiá M, Matta MA, Miró Ò, Murdoch DR, Nuermberger E, Paolini R, Perelló R, Snijders D, Plečko V, Sordé R, Strålin K, van der Eerden MM, Vila-Corcoles A, Watt JP. Estimating the burden of pneumococcal pneumonia among adults: a systematic review and meta-analysis of diagnostic techniques. PLoS One 2013;8(4):e60273.Abstract
BACKGROUND: Pneumococcal pneumonia causes significant morbidity and mortality among adults. Given limitations of diagnostic tests for non-bacteremic pneumococcal pneumonia, most studies report the incidence of bacteremic or invasive pneumococcal disease (IPD), and thus, grossly underestimate the pneumococcal pneumonia burden. We aimed to develop a conceptual and quantitative strategy to estimate the non-bacteremic disease burden among adults with community-acquired pneumonia (CAP) using systematic study methods and the availability of a urine antigen assay.
METHODS AND FINDINGS: We performed a systematic literature review of studies providing information on the relative yield of various diagnostic assays (BinaxNOW® S. pneumoniae urine antigen test (UAT) with blood and/or sputum culture) in diagnosing pneumococcal pneumonia. We estimated the proportion of pneumococcal pneumonia that is bacteremic, the proportion of CAP attributable to pneumococcus, and the additional contribution of the Binax UAT beyond conventional diagnostic techniques, using random effects meta-analytic methods and bootstrapping. We included 35 studies in the analysis, predominantly from developed countries. The estimated proportion of pneumococcal pneumonia that is bacteremic was 24.8% (95% CI: 21.3%, 28.9%). The estimated proportion of CAP attributable to pneumococcus was 27.3% (95% CI: 23.9%, 31.1%). The Binax UAT diagnosed an additional 11.4% (95% CI: 9.6, 13.6%) of CAP beyond conventional techniques. We were limited by the fact that not all patients underwent all diagnostic tests and by the sensitivity and specificity of the diagnostic tests themselves. We address these resulting biases and provide a range of plausible values in order to estimate the burden of pneumococcal pneumonia among adults.
CONCLUSIONS: Estimating the adult burden of pneumococcal disease from bacteremic pneumococcal pneumonia data alone significantly underestimates the true burden of disease in adults. For every case of bacteremic pneumococcal pneumonia, we estimate that there are at least 3 additional cases of non-bacteremic pneumococcal pneumonia.
BACKGROUND: The 2011 GOLD (Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease [COPD]) consensus report uses symptoms, exacerbation history, and forced expiratory volume (FEV1)% to categorise patients according to disease severity and guide treatment. We aimed to assess both the influence of symptom instrument choice on patient category assignment and prospective exacerbation risk by category.
METHODS: Patients were recruited from 21 centres in the USA, as part of the COPDGene study. Eligible patients were aged 45-80 years, had smoked for 10 pack-years or more, and had an FEV1/forced vital capacity (FVC) <0·7. Categories were defined with the modified Medical Research Council (mMRC) dyspnoea scale (score 0-1 vs ≥2) and the St George's Respiratory Questionnaire (SGRQ; ≥25 vs <25 as a surrogate for the COPD Assessment Test [CAT] ≥10 vs <10) in addition to COPD exacerbations in the previous year (<2 vs ≥ 2), and lung function (FEV1% predicted ≥50 vs <50). Statistical comparisons were done with k-sample permutation tests. This study cohort is registered with ClinicalTrials.gov, number NCT00608764.
FINDINGS: 4484 patients with COPD were included in this analysis. Category assignment using the mMRC scale versus SGRQ were similar but not identical. On the basis of the mMRC scale, 1507 (33·6%) patients were assigned to category A, 919 (20·5%) to category B, 355 (7·9%) to category C, and 1703 (38·0%) to category D; on the basis of the SGRQ, 1317 (29·4%) patients were assigned to category A, 1109 (24·7%) to category B, 221 (4·9%) to category C, and 1837 (41·0%) to category D (κ coefficient for agreement, 0·77). Significant heterogeneity in prospective exacerbation rates (exacerbations/person-years) were seen, especially in the D subcategories, depending on the risk factor that determined category assignment (lung function only [0·89, 95% CI 0·78-1·00]), previous exacerbation history only [1·34, 1·0-1·6], or both [1·86, 1·6-2·1; p<0·0001]).
INTERPRETATION: The GOLD classification emphasises the importance of symptoms and exacerbation risk when assessing COPD severity. The choice of symptom measure influences category assignment. The relative number of patients with low symptoms and high risk for exacerbations (category C) is low. Differences in exacerbation rates for patients in the highest risk category D were seen depending on whether risk was based on lung function, exacerbation history, or both.
FUNDING: National Heart, Lung, and Blood Institute, and the COPD Foundation through contributions from AstraZeneca, Boehringer Ingelheim, Novartis, and Sepracor.
Chronic obstructive pulmonary disease (COPD) involves aberrant airway inflammatory responses to cigarette smoke (CS) that are associated with epithelial cell dysfunction, cilia shortening, and mucociliary clearance disruption. Exposure to CS reduced cilia length and induced autophagy in vivo and in differentiated mouse tracheal epithelial cells (MTECs). Autophagy-impaired (Becn1+/- or Map1lc3B-/-) mice and MTECs resisted CS-induced cilia shortening. Furthermore, CS increased the autophagic turnover of ciliary proteins, indicating that autophagy may regulate cilia homeostasis. We identified cytosolic deacetylase HDAC6 as a critical regulator of autophagy-mediated cilia shortening during CS exposure. Mice bearing an X chromosome deletion of Hdac6 (Hdac6-/Y) and MTECs from these mice had reduced autophagy and were protected from CS-induced cilia shortening. Autophagy-impaired Becn1-/-, Map1lc3B-/-, and Hdac6-/Y mice or mice injected with an HDAC6 inhibitor were protected from CS-induced mucociliary clearance (MCC) disruption. MCC was preserved in mice given the chemical chaperone 4-phenylbutyric acid, but was disrupted in mice lacking the transcription factor NRF2, suggesting that oxidative stress and altered proteostasis contribute to the disruption of MCC. Analysis of human COPD specimens revealed epigenetic deregulation of HDAC6 by hypomethylation and increased protein expression in the airways. We conclude that an autophagy-dependent pathway regulates cilia length during CS exposure and has potential as a therapeutic target for COPD.
BACKGROUND: Toll-like receptors (TLRs) on T cells can modulate their responses, however, the extent and significance of TLR expression by lung T cells, NK cells, or NKT cells in chronic obstructive pulmonary disease (COPD) is unknown.
METHODS: Lung tissue collected from clinically-indicated resections (n = 34) was used either: (a) to compare the expression of TLR1, TLR2, TLR2/1, TLR3, TLR4, TLR5, TLR6 and TLR9 on lung CD8+ T cells, CD4+ T cells, NK cells and NKT cells from smokers with or without COPD; or (b) to isolate CD8+ T cells for culture with anti-CD3ε without or with various TLR ligands. We measured protein expression of IFN-γ, TNF-α, IL-13, perforin, granzyme A, granzyme B, soluble FasL, CCL2, CCL3, CCL4, CCL5, CCL11, and CXCL9 in supernatants.
RESULTS: All the lung subsets analyzed demonstrated low levels of specific TLR expression, but the percentage of CD8+ T cells expressing TLR1, TLR2, TLR4, TLR6 and TLR2/1 was significantly increased in COPD subjects relative to those without COPD. In contrast, from the same subjects, only TLR2/1 and TLR2 on lung CD4+ T cells and CD8+ NKT cells, respectively, showed a significant increase in COPD and there was no difference in TLR expression on lung CD56+ NK cells. Production of the Tc1 cytokines IFN-γ and TNF-α by lung CD8+ T cells were significantly increased via co-stimulation by Pam3CSK4, a specific TLR2/1 ligand, but not by other agonists. Furthermore, this increase in cytokine production was specific to lung CD8+ T cells from patients with COPD as compared to lung CD8+ T cells from smokers without COPD.
CONCLUSIONS: These data suggest that as lung function worsens in COPD, the auto-aggressive behavior of lung CD8+ T cells could increase in response to microbial TLR ligands, specifically ligands against TLR2/1.
BACKGROUND: Gas trapping quantified on chest CT scans has been proposed as a surrogate for small airway disease in COPD. We sought to determine if measurements using paired inspiratory and expiratory CT scans may be better able to separate gas trapping due to emphysema from gas trapping due to small airway disease.
METHODS: Smokers with and without COPD from the COPDGene Study underwent inspiratory and expiratory chest CT scans. Emphysema was quantified by the percent of lung with attenuation < -950HU on inspiratory CT. Four gas trapping measures were defined: (1) Exp(-856), the percent of lung < -856HU on expiratory imaging; (2) E/I MLA, the ratio of expiratory to inspiratory mean lung attenuation; (3) RVC(856-950), the difference between expiratory and inspiratory lung volumes with attenuation between -856 and -950 HU; and (4) Residuals from the regression of Exp(-856) on percent emphysema.
RESULTS: In 8517 subjects with complete data, Exp(-856) was highly correlated with emphysema. The measures based on paired inspiratory and expiratory CT scans were less strongly correlated with emphysema. Exp(-856), E/I MLA and RVC(856-950) were predictive of spirometry, exercise capacity and quality of life in all subjects and in subjects without emphysema. In subjects with severe emphysema, E/I MLA and RVC(856-950) showed the highest correlations with clinical variables.
CONCLUSIONS: Quantitative measures based on paired inspiratory and expiratory chest CT scans can be used as markers of small airway disease in smokers with and without COPD, but this will require that future studies acquire both inspiratory and expiratory CT scans.
Hansel NN, Washko GR, Foreman MG, Han MLK, Hoffman EA, DeMeo DL, Barr GR, van Beek EJR, Kazerooni EA, Wise RA, Brown RH, Black-Shinn J, Hokanson JE, Hanania NA, Make B, Silverman EK, Crapo JD, Dransfield MT. Racial differences in CT phenotypes in COPD. COPD 2013;10(1):20-7.Abstract
BACKGROUND: Whether African Americans (AA) are more susceptible to COPD than non-Hispanic Whites (NHW) and whether racial differences in disease phenotype exist is controversial. The objective is to determine racial differences in the extent of emphysema and airway remodeling in COPD.
METHODS: First, 2,500 subjects enrolled in the COPDGene study were used to evaluate racial differences in quantitative CT (QCT) parameters of% emphysema, air trapping and airway wall thickness. Independent variables studied included race, age, gender, education, BMI, pack-years, smoking status, age at smoking initiation, asthma, previous work in dusty job, CT scanner and center of recruitment.
RESULTS: Of the 1,063 subjects with GOLD Stage II-IV COPD, 200 self-reported as AA. AAs had a lower mean% emphysema (13.1% vs. 16.1%, p = 0.005) than NHW and proportionately less emphysema in the lower lung zones. After adjustment for covariates, there was no statistical difference by race in air trapping or airway wall thickness. Measured QCT parameters were more predictive of poor functional status in NHWs compared to AAs.
CONCLUSIONS: AAs have less emphysema than NHWs but the same degree of airway disease. Additional factors not easily assessed by current QCT techniques may account for the poor functional status in AAs.
RATIONALE: Short-term exposure to ambient air pollution has been associated with lower lung function. Few studies have examined whether these associations are detectable at relatively low levels of pollution within current U.S. Environmental Protection Agency (EPA) standards.
OBJECTIVES: To examine exposure to ambient air pollutants within EPA standards and lung function in a large cohort study.
METHODS: We included 3,262 participants of the Framingham Offspring and Third Generation cohorts living within 40 km of the Harvard Supersite monitor in Boston, Massachusetts (5,358 examinations, 1995-2011) who were not current smokers, with previous-day pollutant levels in compliance with EPA standards. We compared lung function (FEV1 and FVC) after previous-day exposure to particulate matter less than 2.5 μm in diameter (PM2.5), nitrogen dioxide (NO2), and ozone (O3) in the "moderate" range of the EPA Air Quality Index to exposure in the "good" range. We also examined linear relationships between moving averages of pollutant concentrations 1, 2, 3, 5, and 7 days before spirometry and lung function.
MEASUREMENTS AND MAIN RESULTS: Exposure to pollutant concentrations in the "moderate" range of the EPA Air Quality Index was associated with a 20.1-ml lower FEV1 for PM2.5 (95% confidence interval [CI], -33.4, -6.9), a 30.6-ml lower FEV1 for NO2 (95% CI, -60.9, -0.2), and a 55.7-ml lower FEV1 for O3 (95% CI, -100.7, -10.8) compared with the "good" range. The 1- and 2-day moving averages of PM2.5, NO2, and O3 before testing were negatively associated with FEV1 and FVC.
CONCLUSIONS: Short-term exposure to PM2.5, NO2, and O3 within current EPA standards was associated with lower lung function in this cohort of adults.
This paper investigates a diffeomorphic point-set registration based on non-stationary mixture models. The goal is to improve the non-linear registration of anatomical structures by representing each point as a general non-stationary kernel that provides information about the shape of that point. Our framework generalizes work done by others that use stationary models. We achieve this by integrating the shape at each point when calculating the point-set similarity and transforming it according to the calculated deformation. We also restrict the non-rigid transform to the space of symmetric diffeomorphisms. Our algorithm is validated in synthetic and human datasets in two different applications: fiber bundle and lung airways registration. Our results shows that nonstationary mixture models are superior to Gaussian mixture models and methods that do not take into account the shape of each point. View full abstract