Oh Sang Young, Lee Minho, Seo Joon Beom, Kim Namkug, Lee Sang Min, Lee Jae Seung, Oh Yeon Mok
Department of Radiology.
Department of Convergence Medicine.
Int J Chron Obstruct Pulmon Dis. 2017 Jul 13;12:2043-2057. doi: 10.2147/COPD.S130081. eCollection 2017.
A novel approach of size-based emphysema clustering has been developed, and the size variation and collapse of holes in emphysema clusters are evaluated at inspiratory and expiratory computed tomography (CT). Thirty patients were visually evaluated for the size-based emphysema clustering technique and a total of 72 patients were evaluated for analyzing collapse of the emphysema hole in this study. A new approach for the size differentiation of emphysema holes was developed using the length scale, Gaussian low-pass filtering, and iteration approach. Then, the volumetric CT results of the emphysema patients were analyzed using the new method, and deformable registration was carried out between inspiratory and expiratory CT. Blind visual evaluations of EI by two readers had significant correlations with the classification using the size-based emphysema clustering method (-values of reader 1: 0.186, 0.890, 0.915, and 0.941; reader 2: 0.540, 0.667, 0.919, and 0.942). The results of collapse of emphysema holes using deformable registration were compared with the pulmonary function test (PFT) parameters using the Pearson's correlation test. The mean extents of low-attenuation area (LAA), E1 (<1.5 mm), E2 (<7 mm), E3 (<15 mm), and E4 (≥15 mm) were 25.9%, 3.0%, 11.4%, 7.6%, and 3.9%, respectively, at the inspiratory CT, and 15.3%, 1.4%, 6.9%, 4.3%, and 2.6%, respectively at the expiratory CT. The extents of LAA, E2, E3, and E4 were found to be significantly correlated with the PFT parameters (=-0.53, -0.43, -0.48, and -0.25), with forced expiratory volume in 1 second (FEV; -0.81, -0.62, -0.75, and -0.40), and with diffusing capacity of the lungs for carbon monoxide (cDLco), respectively. The fraction of emphysema that shifted to the smaller subgroup showed a significant correlation with FEV, cDLco, forced expiratory flow at 25%-75% of forced vital capacity, and residual volume (RV)/total lung capacity (=0.56, 0.73, 0.40, and -0.58). A detailed assessment of the size variation and collapse of emphysema holes may be useful for understanding the dynamic collapse of emphysema and its functional relation.
一种基于大小的肺气肿聚类新方法已经开发出来，并且在吸气和呼气计算机断层扫描（CT）中评估肺气肿聚类中孔洞的大小变化和塌陷情况。本研究中，对30例患者进行了基于大小的肺气肿聚类技术的视觉评估，共72例患者进行了肺气肿孔洞塌陷分析。利用长度尺度、高斯低通滤波和迭代方法开发了一种新的肺气肿孔洞大小区分方法。然后，使用该新方法分析肺气肿患者的容积CT结果，并在吸气和呼气CT之间进行可变形配准。两位读者对肺气肿指数（EI）的盲法视觉评估与基于大小的肺气肿聚类方法的分类具有显著相关性（读者1的相关系数：0.186、0.890、0.915和0.941；读者2的相关系数：0.540、0.667、0.919和0.942）。使用Pearson相关检验将可变形配准得到的肺气肿孔洞塌陷结果与肺功能测试（PFT）参数进行比较。吸气CT时，低衰减区（LAA）、E1（<1.5mm）、E2（<7mm）、E3（<15mm）和E4（≥15mm）的平均范围分别为25.9%、3.0%、11.4%、7.6%和3.9%，呼气CT时分别为15.3%、1.4%、6.9%、4.3%和2.6%。发现LAA、E2、E3和E4的范围与PFT参数（相关系数=-0.53、-0.43、-0.48和-0.25）、一秒用力呼气量（FEV；相关系数=-0.81、-0.62、-0.75和-0.40）以及肺一氧化碳弥散量（cDLco）分别显著相关。转移到较小亚组的肺气肿部分与FEV、cDLco、用力肺活量25%-75%时的用力呼气流量以及残气量（RV）/肺总量显著相关（相关系数=0.56、0.73、0.40和-0.58）。对肺气肿孔洞大小变化和塌陷的详细评估可能有助于理解肺气肿的动态塌陷及其功能关系。
