胸主动脉位置的CT测量及其在纵隔肿瘤诊断中的意义

Position of the thoracic aorta:measurement by CT and its significance in diagnose of mediastinal tumors

目的：探讨纵隔大血管的正常 Ｃ Ｔ 位置及其在纵隔肿瘤诊断中的意义。方法：测量２００ 例正常成人纵隔４ 个 Ｃ Ｔ 层面胸主动脉的位置，并对照分析７ 种８０ 例常见纵隔肿瘤对邻近胸主动脉的推移情况。结果：胸廓正常的成人主动脉弓后内角为２０ ～３７°。升主动脉位于中线右侧１０ ｃｍ至左侧０５ ｃｍ 处，其前后位置位于胸廓正中矢状径中１／３ 的前份。不同的纵隔肿瘤推胸主动脉移位的情况不同。结论：主动脉弓后内角较好地反映了主动脉弓在胸廓内的位置，它以及升主动脉位置的改变可作为判断纵隔肿瘤占位效应的指标。胸腺瘤的占位效应不如纵隔畸胎类肿瘤及淋巴瘤显著。

Aim:To study the normal position of thoracic aorta by CT and its significance in diagnose of mediastinal tumors.Methods: The positions of adult's thoracic aorta were measured on four CT scans by obversing 200 normal mediastinal structures and 80 patients with 7 entities of common mediastinal tumors.Results:The normal postero-medial angle of aortic arch (PMA) was from 20° to 37°. The ascending aorta was 1.0 cm to the right and 0.5 cm to the left of the midline, and located in the anterior half of the middle third of the midsagittal diameter. The shift of the thoracic aorta pushed by various mediastinal tumors was different.Conclusion:PMA of the aortic arch reflected precisely the position of the aortic arch within the chest. The displacement of the thoracic aorta can be regarded as an index in judging space-occupying effect of mediastinal tumor. The space-occupying effect of thymoma is not as obvious as that of teratoid tumors and lymphoma, which is very useful for differential diagnosis of mediastinal tumors.