Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1, Poongnap-dong, Songpa-gu, Seoul 138-736, Korea.
AJR Am J Roentgenol. 2010 Mar;194(3):W248-55. doi: 10.2214/AJR.09.2672.
The purpose of this study was to compare quantitative and visual assessments of regional heterogeneity of emphysema and to investigate the influence of regional heterogeneity on pulmonary function in smoking-related emphysema.
We developed an automatic computerized algorithm to quantitatively assess heterogeneity in the upper-lower, anterior-posterior, and central-peripheral directions. The emphysema index was plotted with a linear function (emphysema index slopes: slope of emphysema index in upper-lower direction, slope of emphysema index in anterior-posterior direction, and slope of emphysema index in central-peripheral direction) for consecutive 1-pixel-thick slices using volumetric CT data of 59 patients (58 men and one woman; mean age, 65.7 years). Emphysema index was defined as the percentage area of lung with attenuation values below -950 HU. Visual assessment was performed using a 5-point scoring system. Quantitative and visual assessments were compared. Multiple linear regression was performed to evaluate the influence of emphysema index and emphysema index slopes on the pulmonary function test.
Quantitative and visual assessments were significantly correlated in both upper-lower (r(2) = 0.40 and r(2) = 0.67 for observers 1 and 2, respectively) and central-peripheral (r(2) = 0.51 and r(2) = 0.47, respectively) directions. Multiple linear regression revealed that emphysema index, slope of emphysema index in upper-lower direction, and slope of emphysema index in anterior-posterior direction were independent determinants of forced expiratory volume in 1 second (FEV(1)) (r(2) = 0.30; p < 0.001). Emphysema index and slope of emphysema index in upper-lower direction were independent determinants of the ratio of FEV(1) to forced vital capacity (FEV(1)/FVC) (r(2) = 0.32; p < 0.001). In addition to higher emphysema index, lower and posterior lung dominance was associated with a decrease in FEV(1) and FEV(1)/FVC.
Computerized, quantitative assessment using the emphysema index slope is comparable to visual assessment in the evaluation of regional heterogeneity of emphysema. In addition to the emphysema index, regional heterogeneity of smoking-related emphysema contributes to impairment of pulmonary function.
本研究旨在比较肺气肿区域异质性的定量和视觉评估，并探讨区域异质性对吸烟相关性肺气肿患者肺功能的影响。
我们开发了一种自动计算机算法，用于定量评估上-下、前-后和中央-外周方向的异质性。使用 59 例患者（58 名男性和 1 名女性；平均年龄 65.7 岁）的容积 CT 数据，用线性函数（肺气肿指数斜率：上-下方向肺气肿指数斜率、前-后方向肺气肿指数斜率和中央-外周方向肺气肿指数斜率）绘制肺气肿指数图。肺气肿指数定义为衰减值低于-950 HU 的肺区域百分比面积。采用 5 分制进行视觉评估。比较定量和视觉评估。采用多元线性回归评估肺气肿指数和肺气肿指数斜率对肺功能检查的影响。
上-下（观察者 1 和 2 的 r²分别为 0.40 和 0.67）和中央-外周（r²分别为 0.51 和 0.47）方向的定量和视觉评估均显著相关。多元线性回归显示，肺气肿指数、上-下方向肺气肿指数斜率和前-后方向肺气肿指数斜率是 1 秒用力呼气量（FEV1）的独立决定因素（r²=0.30；p<0.001）。肺气肿指数和上-下方向肺气肿指数斜率是 FEV1 与用力肺活量（FEV1/FVC）比值的独立决定因素（r²=0.32；p<0.001）。除了肺气肿指数较高外，下肺和后肺优势与 FEV1 和 FEV1/FVC 下降有关。
使用肺气肿指数斜率进行计算机化定量评估与视觉评估在评估肺气肿的区域异质性方面具有可比性。除了肺气肿指数外，吸烟相关性肺气肿的区域异质性也会导致肺功能受损。
