Department of Medical Imaging, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
Eur J Radiol. 2012 Nov;81(11):3581-6. doi: 10.1016/j.ejrad.2011.12.015. Epub 2012 Jan 10.
The thymus changes with age. Its shape and the proportion of solid tissue and fat vary between individuals, yet there is no comprehensive work describing the size and morphology of the normal thymus on CT. As a result, many adults with some preserved soft tissue in the thymus may undergo extensive work-up to exclude mediastinal tumor. Our aim was to quantify CT characteristics of the normal thymus in an adult population.
CT chest scans of 194 trauma patients aged 14-78 years (mean 52.6 years), were retrospectively reviewed. The density, volume, shape and predominant side of the thymus were recorded for 56 patients in whom some solid tissue was preserved. Statistical analysis of these characteristics according to the patient age and gender was performed.
Thymic density and volume decreased progressively with age. No solid tissue component was seen in the thymus in patients older than 54 years. In the majority of patients, the thymus had an arrowhead shape, with middle position. However, great variability in thymic shape and border were noted. There was a highly significant relationship between density and patient age (p<0.0001).
We hope that our work will help in the definition of normal thymic CT parameters in adults, help to prevent unnecessary and expensive imaging procedures, and reduce patient exposure to ionizing radiation.
胸腺随年龄而变化。其形状和实质组织与脂肪的比例在个体之间有所不同，但目前尚无全面描述 CT 上正常胸腺大小和形态的工作。因此，许多保留有部分软组织的成年人可能需要进行广泛的检查以排除纵隔肿瘤。我们的目的是量化成年人正常胸腺的 CT 特征。
回顾性分析了 194 例年龄在 14-78 岁（平均 52.6 岁）的创伤患者的胸部 CT 扫描。对 56 例保留部分实质组织的患者记录了胸腺的密度、体积、形状和优势侧。根据患者年龄和性别对这些特征进行了统计学分析。
胸腺密度和体积随年龄逐渐下降。54 岁以上患者的胸腺内未见任何实质组织成分。在大多数患者中，胸腺呈箭头形，位于中间位置。然而，胸腺的形状和边界存在很大的可变性。密度与患者年龄之间存在高度显著的关系（p<0.0001）。
我们希望我们的工作将有助于确定成年人正常胸腺 CT 参数，有助于避免不必要和昂贵的影像学检查，并减少患者接受电离辐射的机会。
