Purpose

The primary and secondary aims were to investigate the prevalence of incidental mediastinal masses on low-dose chest CT examinations during health check-ups, and to review the radiological characteristics of prevascular mediastinal masses, respectively.

Materials and methods

This retrospective study included 38,861 participants (mean age: 57.1 years; range: 21–99 years; men: 51.3%; never-smokers: 57.4%) who underwent low-dose chest CT examinations between January 2011 and December 2016. All images with incidental mediastinal masses were reviewed, and prevascular mediastinal masses were assessed for qualitative and quantitative imaging characteristics by two radiologists. Univariate and multivariate analyses were performed in clinical and CT features between some combinations of participants.

Results

Overall, 653 participants (1.68%, 653 of 38,861) had incidental mediastinal masses; 578 in prevascular mediastinum, including 93 intrathymic cysts and 24 thymic epithelial tumors. Presence of mediastinal mass was not significantly associated with sex (p = 0.089) and smoking history (p = 0.098) but with age (p < 0.001). Significant differences were found between intrathymic cysts and thymic epithelial tumors in terms of shapes (p = 0.049), contours (p = 0.018), and CT values (p = 0.012).

Conclusion

The prevalence of asymptomatic mediastinal masses on low-dose chest CT was 1.68%. CT values, shapes, and contours may effectively distinguish intrathymic cysts from thymic epithelial tumors.

中文翻译：

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低剂量CT筛查发现的偶然纵隔肿块：患病率和放射学特征。

目的

主要和次要目的是调查健康检查期间低剂量胸部CT检查中偶然的纵隔肿块的患病率，并分别回顾血管前纵隔肿块的放射学特征。

材料和方法

这项回顾性研究包括38,861名参与者（2011年1月至2016年12月）接受了低剂量胸部CT检查（平均年龄：57.1岁；范围：21–99岁；男性：51.3％；从不吸烟者：57.4％）。回顾了偶然的纵隔肿块，并由两名放射科医生评估了血管前纵隔肿块的定性和定量成像特征。在参与者的某些组合之间的临床和CT特征中进行了单因素和多因素分析。

结果

总体上，有653名参与者（1.68％，在38,861名中有653名）有偶然的纵隔肿块。578个血管前纵隔，包括93个胸腺内囊肿和24个胸腺上皮肿瘤。纵隔肿物的存在与性别（p  = 0.089）和吸烟史（p  = 0.098）无关，而与年龄（p  <0.001）显着相关。发现胸腺内囊肿与胸腺上皮肿瘤在形状（p  = 0.049），轮廓（p  = 0.018）和CT值（p  = 0.012）方面存在显着差异。

结论

低剂量胸部CT的无症状纵隔肿块患病率为1.68％。CT值，形状和轮廓可有效区分胸腺内囊肿与胸腺上皮肿瘤。