Browsing by Author "Washko, George R."

Now showing 1 - 11 of 11
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    Airway Count and Emphysema Assessed by Chest CT Imaging Predicts Clinical Outcome in Smokers
    (ELSEVIER, 2010) Diaz, Alejandro A.; Valim, Clarissa; Yamashiro, Tsuneo; San Jose Estepar, Raul; Ross, James C.; Matsuoka, Shin; Bartholmai, Brian; Hatabu, Hiroto; Silverman, Edwin K.; Washko, George R.
    Background: Recently, it has been shown that emphysematous destruction of the lung is associated with a decrease in the total number of terminal bronchioles. It is unknown whether a similar decrease is visible in the more proximal airways. We aimed to assess the relationships between proximal airway count, CT imaging measures of emphysema, and clinical prognostic factors in smokers, and to determine whether airway count predicts the BMI, airflow obstruction, dyspnea, and exercise capacity (BODE) index.
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    Airway wall attenuation: a biomarker of airway disease in subjects with COPD
    (AMER PHYSIOLOGICAL SOC, 2009) Washko, George R.; Dransfield, Mark T.; Estepar, Raul San Jose; Diaz, Alejandro; Matsuoka, Shin; Yamashiro, Tsuneo; Hatabu, Hiroto; Silverman, Edwin K.; Bailey, William C.; Reilly, John J.
    Washko GR, Dransfield MT, Estepar RS, 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 107: 185-191, 2009. First published April 30, 2009; doi:10.1152/japplphysiol.00216.2009.-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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    Collapsibility of Lung Volume by Paired Inspiratiory and Expiratory CT Scans: Correlations with Lung Function and Mean Lung Density
    (ELSEVIER SCIENCE INC, 2010) Yamashiro, Tsuneo; Matsuoka, Shin; Bartholmai, Brian J.; Estepar, Raul San Jose; Ross, James C.; Diaz, Alejandro; Murayama, Sadayuki; Silverman, Edwin K.; Hatabu, Hiroto; Washko, George R.
    Rationale and Objectives: To evaluate the relationship between measurements of lung volume (LV) on inspiratory/expiratory computed tomography (CT) scans, pulmonary function tests (PFT), and CT measurements of emphysema in individuals with chronic obstructive pulmonary disease.
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    CT and physiologic determinants of dyspnea and exercise capacity during the six-minute walk test in mild COPD
    (2013) Díaz, Alejandro A.; Morales, Arturo; Díaz, Juan Carlos; Ramos, Cristóbal; Klaassen Lobos, Julieta Isabel; Saldías Peñafiel, Fernando; Aravena León, Carlos Andrés; Díaz, Rodrigo; Lisboa Basualto, Carmen; Washko, George R.; Díaz, Orlando
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    Kurtosis and Skewness of Density Histograms on Inspiratory and Expiratory CT Scans in Smokers
    (INFORMA HEALTHCARE, 2011) Yamashiro, Tsuneo; Matsuoka, Shin; Estepar, Raul San Jose; Bartholmai, Brian J.; Diaz, Alejandro; Ross, James C.; Murayama, Sadayuki; Silverman, Edwin K.; Hatabu, Hiroto; Washko, George R.
    The aim of this study is to evaluate the relationship between lung function and kurtosis or skewness of lung density histograms on computed tomography (CT) in smokers. Forty-six smokers (age range 46-81 years), enrolled in the Lung Tissue Research Consortium, underwent pulmonary function tests (PFT) and chest CT at full inspiration and full expiration. On both inspiratory and expiratory scans, kurtosis and skewness of the density histograms were automatically measured by open-source software. Correlations between CT measurements and lung function were evaluated by the linear regression analysis. Although no significant correlations were found between inspiratory kurtosis or skewness and PFT results, expiratory kurtosis significantly correlated with the following: the percentage of predicted value of forced expiratory volume in the first second (FEV1), the ratio of FEV1 to forced vital capacity (FVC), and the ratio of residual volume (RV) to total lung capacity (TLC) (FEV1%predicted, R = -0.581, p < 0.001; FEV1/FVC, R = -0.612, p < 0.001; RV/TLC, R = 0.613, p < 0.001, respectively). Similarly, expiratory skewness showed significant correlations with PFT results (FEV1%predicted, R = -0.584, p < 0.001; FEV1/FVC, R = -0.619, p < 0.001; RV/TLC, R = 0.585, p < 0.001, respectively). Also, the expiratory/inspiratory (E/I) ratios of kurtosis and skewness significantly correlated with FEV1%predicted (p < 0.001), FEV1/FVC (p < 0.001), RV/TLC (p < 0.001), and the percentage of predicted value of diffusing capacity for carbon monoxide (kurtosis E/I ratio, p = 0.001; skewness E/I ratio, p = 0.03, respectively). We conclude therefore that expiratory values and the E/I ratios of kurtosis and skewness of CT densitometry reflect airflow limitation and air-trapping. Higher kurtosis or skewness on expiratory CT scan indicates more severe conditions in smokers.
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    Physiological and Computed Tomographic Predictors of Outcome from Lung Volume Reduction Surgery
    (AMER THORACIC SOC, 2010) Washko, George R.; Martinez, Fernando J.; Hoffman, Eric A.; Loring, Stephen H.; Estepar, Raul San Jose; Diaz, Alejandro A.; Sciurba, Frank C.; Silverman, Edwin K.; Han, MeiLan K.; DeCamp, Malcolm; Reilly, John J.; Natl Emphysema Treatment Trial Res
    Rationale: Previous investigations have identified several potential predictors of outcomes from lung volume reduction surgery (LVRS). A concern regarding these studies has been their small sample size, which may limit generalizability. We therefore sought to examine radiographic and physiologic predictors of surgical outcomes in a large, multicenter clinical investigation, the National Emphysema Treatment Trial.
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    Pulmonary lobe segmentation based on ridge surface sampling and shape model fitting
    (2013) Ross, James C.; Kindlmann, Gordon L.; Okajima, Yuka; Hiroto Hatabu, Díaz Fuenzalida, Alejandro; Silverman, Edwin K.; Washko, George R.; Dy, Jennifer; San José Estépar, Raúl
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    Quantitative Airway Assessment on Computed Tomography in Patients with alpha(1)-antitrypsin Deficiency
    (TAYLOR & FRANCIS INC, 2009) Yamashiro, Tsuneo; Matsuoka, Shin; Estepar, Raul San Jose; Diaz, Alejandro; Newell, John D.; Sandhaus, Robert A.; Mergo, Patricia J.; Brantly, Mark L.; Murayama, Sadayuki; Reilly, John J.; Hatabu, Hiroto; Silverman, Edwin K.; Washko, George R.
    The relationship between quantitative airway measurements on computed tomography (CT) and airflow limitation in individuals with severe alpha(1)-antitrypsin deficiency (AATD) is undefined. Thus, we planned to clarity the relationship between CT-based airway indices and airflow limitation in AATD. 52 patients with AATD underwent chest CT and pre-bronchodilator spirometry at three institutions. In the right upper (RUL) and lower (RLL) lobes, wall area percent (WA%) and luminal area (Ai) were measured in the third, fourth, and fifth generations of the bronchi. The severity of emphysema was also calculated in each lobe and expressed as low attenuation area percent (LAA%). Correlations between obtained measurements and FEV1% predicted (FEV1%P) were evaluated by the Spearman rank correlation test. In RUL, WA% of all generations was significantly correlated with FEV1%P (3rd, R = -0.33, p = 0.02; 4th, R = -0.39, p = 0.004; 5th, R = -0.57, p < 0.001; respectively). Ai also showed significant correlations (3rd, R = 0.32, p = 0.02; 4th, R = 0.34, p = 0.01; 5th, R = 0.56, p < 0.001; respectively). Measured correlation coefficients improved when the airway progressed distally from the third to fifth generations. LAA% also correlated with FEV1%P (R = -0.51, p < 0.001). In RLL, WA% showed weak correlations with FEV1%P in all generations (3rd, R = -0.34, p = 0.01; 4th, R = -0.30, P = 0.03; 5th, R = -0.31, p = 0.03; respectively). Only Ai from the fifth generation significantly correlated with FEV1%P in this lobe (R = 0.34, p = 0.01). LAA% strongly correlated with FEV1%P (R = -0.71, p < 0.001). We conclude therefore that quantitative airway measurements are significantly correlated with airflow limitation in AATD, particularly in the distal air-ways of RUL. Emphysema of the lower lung is the predominant component; however, airway disease also has a significant impact on airflow limitation in AATD.
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    Quantitative Assessment of Bronchial Wall Attenuation With Thin-Section CT: An Indicator of Airflow Limitation in Chronic Obstructive Pulmonary Disease
    (AMER ROENTGEN RAY SOC, 2010) Yamashiro, Tsuneo; Matsuoka, Shin; Estepar, Raul San Jose; Dransfield, Mark T.; Diaz, Alejandro; Reilly, John J.; Patz, Samuel; Murayama, Sadayuki; Silverman, Edwin K.; Hatabu, Hiroto; Washko, George R.
    OBJECTIVE. The purpose of this study was to evaluate the relation between bronchial wall attenuation on thin-section CT images and airflow limitation in persons with chronic obstructive pulmonary disease. SUBJECTS AND
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    Quantitative CT Measurement of Cross-sectional Area of Small Pulmonary Vessel in COPD: Correlations with Emphysema and Airflow Limitation
    (ELSEVIER SCIENCE INC, 2010) Matsuoka, Shin; Washko, George R.; Dransfield, Mark T.; Yamashiro, Tsuneo; Estepar, Raul San Jose; Diaz, Alejandro; Silverman, Edwin K.; Patz, Samuel; Hatabu, Hiroto
    Rationale and Objectives: Pulmonary vascular alteration is one of the characteristic features of chronic obstructive pulmonary disease (COPD). Recent studies suggest that vascular alteration is closely related to endothelial dysfunction and may be further influenced by emphysema. However, the relationship between morphological alteration of small pulmonary vessels and the extent of emphysema has not been assessed in vivo. The objectives of this study are: to evaluate the correlation of total cross-sectional area (CSA) of small pulmonary vessels with the extent of emphysema and airflow obstruction using CT scans and to assess the difference of total CSA between COPD phenotypes.
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    Relationship of emphysema and airway disease assessed by CT to exercise capacity in COPD
    (W B SAUNDERS CO LTD, 2010) Diaz, Alejandro A.; Bartholmai, Brian; Estepar, Raul San Jose; Ross, James; Matsuoka, Shin; Yamashiro, Tsuneo; Hatabu, Hiroto; Reilly, John J.; Silverman, Edwin K.; Washko, George R.
    Objective: To assess the association of emphysema and airway disease assessed by volumetric computed tomography (CT) with exercise capacity in subjects with chronic obstructive pulmonary disease (COPD).