目的　探讨胸廓径线比值与男性原发性自发性气胸（PSP）之间的关系。  方法　研究对象为2017年7月至2018年6月本科收治男性PSP患者44名，对照组为同年龄段体检健康男性30名。采集胸部CT影像数据，用Mimics Medical 20.0软件完成肺与胸廓的三维重建，计算肺高度H；在胸骨柄第1肋软骨、胸骨角、隆突、胸骨体末端、剑突末端共5个层面分别测量胸廓最大横径T（内壁左右两侧最大距离），前后径D（所在平面的胸骨与脊柱间垂直距离）。比较两组间扁平指数（flat index，FI=T/D），狭长指数（slim index，SI=H/D），上下径与横径比值（height transverse ratio，HTR=H/T）。对有显著性差异的数值进行PSP发生的相关性分析，对最大相关因素做二分类Logistic回归分析。  结果　两组间各径线比值有显著差异。按年龄段分层比较发现，PSP发生的最大相关因素为SI5（剑突末端层面），R=0.682，R2=0.465，P<0.01。二分类logistic回归计算SI5与PSP发生的关系，发现其预测准确率为82.40%，OR值为276.49，95%可信区间是21.20~3606.67，P<0.01。  结论　剑突末端平面的SI是PSP发生的最大相关因素。相较胸廓扁平程度，胸廓狭长程度与PSP具有更大相关性。剑突区域胸廓前后径偏小可能是PSP致病因素之一。

Objective　To investigate the correlation between the ratio of thorax diameter and spontaneous pneumothorax (PSP) in males.　Methods　Forty-four male patients with PSP were admitted in the department of thoracic surgery of the central hospital of Wuhan from July 2017 to June 2018. The control group was 30 healthy men of the same age. CT data of chest were collected, and the lung and thorax were reconstructed with Mimics Medical 20.0 software to calculate the lung height H. The maximum transverse diameter T (maximum distance between the left and right sides of the inner wall of the thorax) and the anterior and posterior diameter D (vertical distance from sternum to spine in the plane) were measured respectively at five planes (plane of first costal cartilage, sternal angle, carina, end of sternum and end of xiphoid). Flat index (FI=T/D), slim index (SI=H/D), height transverse ratio (HTR=H/T) were compared between the two groups. Correlation analysis of pneumothorax occurrence was performed on the values with significant differences, and binary logistic regression analysis was performed on the greatest related factor.　Results　Significant differences were showed in the diameter ratios between the two groups. According to age stratification, SI5 (the plane of the xiphoid end) was the most important risk factors for PSP (R=0.682, R2=0.465, P<0.01). The predictive accuracy of SI5 was 82.40%, OR was 276.49, 95% confidence interval was 21.20~3606.67(P<0.01).　Conclusion　The SI at the end of xiphoid is the most relevant factor for PSP. Compared with the degree of thoracic flatten, the slim degree is more correlated with PSP. Smaller anteroposterior diameter of the xphoid region is probably one of the pathogenic factors.