Dataset Information

CT-derived Biomechanical Metrics Improve Agreement Between Spirometry and Emphysema.

ABSTRACT: RATIONALE AND OBJECTIVES:Many patients with chronic obstructive pulmonary disease (COPD) have marked discordance between forced expiratory volume in 1 second (FEV1) and degree of emphysema on computed tomography (CT). Biomechanical differences between these patients have not been studied. We aimed to identify reasons for the discordance between CT and spirometry in some patients with COPD. MATERIALS AND METHODS:Subjects with Global initiative for chronic Obstructive Lung Disease stages I-IV from a large multicenter study (The Genetic Epidemiology of COPD) were arranged by percentiles of %predicted FEV1 and emphysema on CT. Three categories were created using differences in percentiles: Catspir with predominant airflow obstruction/minimal emphysema, CatCT with predominant emphysema/minimal airflow obstruction, and Catmatched with matched FEV1 and emphysema. Image registration was used to derive Jacobian determinants, a measure of lung elasticity, anisotropy, and strain tensors, to assess biomechanical differences between groups. Regression models were created with the previously mentioned categories as outcome variable, adjusting for demographics, scanner type, quantitative CT-derived emphysema, gas trapping, and airway thickness (model 1), and after adding biomechanical CT metrics (model 2). RESULTS:Jacobian determinants, anisotropy, and strain tensors were strongly associated with FEV1. With Catmatched as control, model 2 predicted Catspir and CatCT better than model 1 (Akaike information criterion 255.8 vs. 320.8). In addition to demographics, the strongest independent predictors of FEV1 were Jacobian mean (??=?1.60,95%confidence intervals [CI]?=?1.16 to 1.98; P?

SUBMITTER: Bhatt SP

PROVIDER: S-EPMC5026854 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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CT-derived Biomechanical Metrics Improve Agreement Between Spirometry and Emphysema.

Bhatt Surya P SP Bodduluri Sandeep S Newell John D JD Hoffman Eric A EA Sieren Jessica C JC Han Meilan K MK Dransfield Mark T MT Reinhardt Joseph M JM

Academic radiology 20160404 10

<h4>Rationale and objectives</h4>Many patients with chronic obstructive pulmonary disease (COPD) have marked discordance between forced expiratory volume in 1 second (FEV1) and degree of emphysema on computed tomography (CT). Biomechanical differences between these patients have not been studied. We aimed to identify reasons for the discordance between CT and spirometry in some patients with COPD.<h4>Materials and methods</h4>Subjects with Global initiative for chronic Obstructive Lung Disease s ...[more]

PMID: 27055745

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Project description:ObjectiveTo empirically explore the level of agreement of the treatment hierarchies from different ranking metrics in network meta-analysis (NMA) and to investigate how network characteristics influence the agreement.DesignEmpirical evaluation from re-analysis of NMA.Data232 networks of four or more interventions from randomised controlled trials, published between 1999 and 2015.MethodsWe calculated treatment hierarchies from several ranking metrics: relative treatment effects, probability of producing the best value [Formula: see text] and the surface under the cumulative ranking curve (SUCRA). We estimated the level of agreement between the treatment hierarchies using different measures: Kendall's τ and Spearman's ρ correlation; and the Yilmaz [Formula: see text] and Average Overlap, to give more weight to the top of the rankings. Finally, we assessed how the amount of the information present in a network affects the agreement between treatment hierarchies, using the average variance, the relative range of variance and the total sample size over the number of interventions of a network.ResultsOverall, the pairwise agreement was high for all treatment hierarchies obtained by the different ranking metrics. The highest agreement was observed between SUCRA and the relative treatment effect for both correlation and top-weighted measures whose medians were all equal to 1. The agreement between rankings decreased for networks with less precise estimates and the hierarchies obtained from [Formula: see text] appeared to be the most sensitive to large differences in the variance estimates. However, such large differences were rare.ConclusionsDifferent ranking metrics address different treatment hierarchy problems, however they produced similar rankings in the published networks. Researchers reporting NMA results can use the ranking metric they prefer, unless there are imprecise estimates or large imbalances in the variance estimates. In this case treatment hierarchies based on both probabilistic and non-probabilistic ranking metrics should be presented.

Project description:BackgroundTobacco smoking may cause pulmonary perfusion abnormality. Assessment of the lung perfusion characteristics is very significant to timely treatment and prevent disease progression in smokers. The purpose was to investigate the value of iodine maps from spectral dual-layer detector computed tomography (DLCT) in assessing lung perfusion changes in smokers.MethodsNineteen smokers and 29 non-smokers who underwent dual-phase contrast enhanced scans on a spectral DLCT were retrospectively collected. Emphysema on non-contrast images and perfusion defect (PD) on iodine maps were scored visually at bilateral lung fields of three anatomic levels (on the slice of the aortic arch, the carina, and the aperture of the inferior pulmonary veins). The scores were calculated based on the ratio of the abnormality occupied in the pulmonary field of each slice as described below: point 0, no abnormality; point 1, 0%< abnormality scope ≤25%; points 2, 25%< abnormality scope ≤50%; points 3, 50%< abnormality scope ≤75%; points 4, abnormality scope >75%. The sum of scores for each patient was calculated. The iodine density (ID) of PD and thoracic aorta were measured respectively (IDdefect, IDthoracic aorta), then calculating the ratio as the normalized ID (nID). Emphysema index (EI) was defined as the volume percentage of the lung attenuation below -950 Hounsfield units. The percentage of forced expiratory volume in 1 second (FEV1) to the predicted value (FEV1%) and the ratio of FEV1 to forced vital capacity (FVC) were recorded. The differences of the emphysema and PD visual scores, IDdefect, nID, EI were analyzed by analysis of variance between smokers and non-smokers. Correlations between emphysema, PD and FEV1%, FEV1/FVC were evaluated by Spearman correlation analysis.ResultsThe PD visual scores on ID images were significantly higher in smokers compared with that in non-smokers (P=0.014), while no significantly difference was found for emphysema visual scores (P=0.402). Both IDdefect and nID were significantly lower in smokers compared with non-smokers (P=0.003; P=0.029), while no significantly difference was found for EI (P=0.061). Besides, PD visual scores were negatively correlated with FEV1% (r=-0.61, P=0.025) and FEV1/FVC (r=-0.62, P=0.024) for smokers.ConclusionsCompared with emphysema, the iodine map derived from spectral DLCT showed higher sensitivity for the evaluation of the pulmonary abnormalities of smokers.

Project description:Background and objectiveThis study aimed to investigate whether quantitative lung vessel morphology determined by a new fully automated algorithm is associated with functional indices in idiopathic pulmonary fibrosis (IPF).MethodsA total of 152 IPF patients had vessel volume, density, tortuosity and heterogeneity quantified from computed tomography (CT) images by a fully automated algorithm. Separate quantitation of vessel metrics in pulmonary arteries and veins was performed in 106 patients. Results were evaluated against readouts from lung function tests.ResultsNormalized vessel volume expressed as a percentage of total lung volume was moderately correlated with functional indices on univariable linear regression analysis: forced vital capacity (R2 = 0.27, P < 1 × 10-6 ), diffusion capacity for carbon monoxide (DLCO ; R2 = 0.12, P = 3 × 10-5 ), total lung capacity (TLC; R2 = 0.45, P < 1 × 10-6 ) and composite physiologic index (CPI; R2 = 0.28, P < 1 × 10-6 ). Normalized vessel volume was correlated with vessel density but not with vessel heterogeneity. Quantitatively derived vessel metrics (and artery and vein subdivision scores) were not significantly linked with the transfer factor for carbon monoxide (KCO ), and only weakly with DLCO . On multivariable linear regression analysis, normalized vessel volume and vessel heterogeneity were independently linked with DLCO , TLC and CPI indicating that they capture different aspects of lung damage. Artery-vein separation provided no additional information beyond that captured in the whole vasculature.ConclusionOur study confirms previous observations of links between vessel volume and functional measures of disease severity in IPF using a new vessel quantitation tool. Additionally, the new tool shows independent linkages of normalized vessel volume and vessel heterogeneity with functional indices. Quantitative vessel metrics do not appear to reflect vasculopathic damage in IPF.

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CT-derived Biomechanical Metrics Improve Agreement Between Spirometry and Emphysema.

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CT-derived Biomechanical Metrics Improve Agreement Between Spirometry and Emphysema.

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