Dataset Information

The characteristics of emphysema and pulmonary perfusion derived from spectral CT in smokers.

ABSTRACT:

Background

Tobacco 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.

Methods

Nineteen 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 (ID_defect, ID_{thoracic 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, ID_defect, 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.

Results

The 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 ID_defect 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.

Conclusions

Compared with emphysema, the iodine map derived from spectral DLCT showed higher sensitivity for the evaluation of the pulmonary abnormalities of smokers.

SUBMITTER: Guan Y

PROVIDER: S-EPMC10713300 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature

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Publications

The characteristics of emphysema and pulmonary perfusion derived from spectral CT in smokers.

Guan Yu Y Zhou Xiuxiu X Zhang Di D Xia Yi Y Liu Shiyuan S Fan Li L

Journal of thoracic disease 20231117 11

<h4>Background</h4>Tobacco 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.<h4>Methods</h4>Nineteen smokers and 29 non-smokers who underwent dual-phase contrast enhanced scans on a spectral DLCT were ...[more]

PMID: 38090318

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Project description:Background The correlation between visual emphysema patterns and subsequent progression of disease may provide a way to enrich a study population for treatment trials of emphysema. Purpose To evaluate the potential relationship between emphysema visual subtypes and progression of emphysema and gas trapping. Materials and Methods Current and former smokers with and without chronic obstructive pulmonary disease (COPD) enrolled in the prospective Genetic Epidemiology of COPD (COPDGene) study (ClinicalTrials.gov identifier: NCT02445183) between 2008 and 2011 had their Fleischner Society visual CT scores assessed at baseline, quantitative inspiratory, and expiratory CT and at 5 years. They also underwent pulmonary function testing at baseline CT and at 5 years. The dependent variables were inspiratory lung density at 15th percentile (adjusted for lung volume) as a measure of emphysema and percentage of lung volume with attenuation less than -856 HU at expiratory CT as a measure of air trapping. Statistical analysis used a linear mixed model, adjusted for age, height, sex, race, smoking status, and scanner make. Results A total of 4166 participants (mean age, 60 years ± 9 [standard deviation]; 2091 [50%] men) were evaluated. In participants with COPD (1655 participants, 40%), those with visual presence of mild, moderate, and confluent emphysema at baseline CT showed a mean decline in lung density of 4.6 g/L ± 1.1 (P < .001), 6.7 g/L ± 1.1 (P < .001), and 6.4 g/L ± 1.2 (P < .001), respectively, compared with 2.4 g/L ± 1.3 (P < .001) for those with trace emphysema. For participants without COPD, those with visual presence of mild and moderate emphysema at baseline CT showed a mean decline in lung density of 3.6 g/L ± 1.0 (P < .001) and 3.1 g/L ± 1.6 (P < .001), respectively, compared with 1.8 g/L ± 1.0 (P < .001) for those with trace emphysema. Conclusion The pattern of parenchymal emphysema at baseline CT was an independent predictor of subsequent progression of emphysema in participants who are current or former cigarette smokers with and without chronic obstructive pulmonary disease. © RSNA, 2020 Online supplemental material is available for this article.

Project description:Rationale and objectivesMany 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 methodsSubjects 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).ResultsJacobian determinants, anisotropy, and strain tensors were strongly associated with FEV1. With Catmatched as control, model 2 predicted Catspir and CatCT better than model 1 (Akaike information criterion 255.8 vs. 320.8). In addition to demographics, the strongest independent predictors of FEV1 were Jacobian mean (β = 1.60,95%confidence intervals [CI] = 1.16 to 1.98; P < 0.001), coefficient of variation (CV) of Jacobian (β = 1.45,95%CI = 0.86 to 2.03; P < 0.001), and CV of strain (β = 1.82,95%CI = 0.68 to 2.95; P = 0.001). CVs of Jacobian and strain are both potential markers of biomechanical lung heterogeneity.ConclusionsCT-derived measures of lung mechanics improve the link between quantitative CT and spirometry, offering the potential for new insights into the linkage between regional parenchymal destruction and global decrement in lung function in patients with COPD.

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Dataset Information

The characteristics of emphysema and pulmonary perfusion derived from spectral CT in smokers.

Background

Methods

Results

Conclusions

Publications

The characteristics of emphysema and pulmonary perfusion derived from spectral CT in smokers.

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