TY - JOUR
T1 - Kurtosis and skewness of density histograms on inspiratory and expiratory CT scans in smokers
AU - Yamashiro, Tsuneo
AU - Matsuoka, Shin
AU - Estépar, Raúl San José
AU - Bartholmai, Brian J.
AU - Diaz, Alejandro
AU - Ross, James C.
AU - Murayama, Sadayuki
AU - Silverman, Edwin K.
AU - Hatabu, Hiroto
AU - Washko, George R.
N1 - Funding Information:
This study is supported by NIH K23HL089353-01A1 and a grant from the Parker B. Francis Foundation. This study utilized data provided by the Lung Tissue Research Consortium (LTRC) supported by the National Heart, Lung, and Blood Institute (NHLBI). This study is supported by NIH K23HL089353-01A1 and a grant from the Parker B. Francis Foundation. The authors thank Alba Cid, MS, and Kerianne R. Panos, MS, for their assistance in revising the manuscript. Dr. Yamashiro, Dr. Matsuoka, Dr. San Jose Estepar, Dr. Bartholmai, Mr. Ross, Dr. Diaz, Dr. Murayama, Dr. Hatabu, and Dr. Washko have no conflicts of interest to disclose. Dr. Silverman received an honorarium for a talk on COPD genetics in 2006, and grant support and consulting fees from GlaxoSmithKline for two studies of COPD genetics. Dr. Silverman also received honoraria from Bayer in 2005, and from AstraZeneca in 2007 and 2008. The authors alone are responsible for the content and writing of the paper. Abbreviations: FEV1, forced expiratory volume in the first second; FVC, forced vital capacity; RV, residual volume; TLC, total lung capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease Correspondence to: Tsuneo Yamashiro, MD, Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa 903-0215, Japan, phone: +81-98-895-1162, fax: +81-98-895-1420. email: clatsune@yahoo.co.jp
PY - 2011/2
Y1 - 2011/2
N2 - 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.
AB - 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.
KW - Airflow limitation
KW - Chronic obstructive pulmonary disease
KW - Computed tomography
KW - Density histogram
KW - Pulmonary emphysema
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U2 - 10.3109/15412555.2010.541537
DO - 10.3109/15412555.2010.541537
M3 - Article
C2 - 21299474
AN - SCOPUS:79851486419
SN - 1541-2555
VL - 8
SP - 13
EP - 20
JO - COPD: Journal of Chronic Obstructive Pulmonary Disease
JF - COPD: Journal of Chronic Obstructive Pulmonary Disease
IS - 1
ER -