Department of Imagiology, Hospital-Escola da Universidade Fernando Pessoa, Gondomar, Porto, Portugal,
Insights Imaging. 2013 Dec;4(6):759-72. doi: 10.1007/s13244-013-0278-0. Epub 2013 Sep 25.
Air/gas outside the aero-digestive tract is abnormal; depending on its location, it is usually called emphysema, referring to trapped air/gas in tissues, or ectopic air/gas. It can be associated to a wide range of disorders, and although it usually is an innocuous condition, it should prompt a search for the underlying aetiology, since some of its causes impose an urgent treatment. In rare instances, it may itself represent a life-threatening condition, depending on the site involved and how quickly it evolves. Abnormal air/gas beyond viscera and serosal spaces, reaches its location following some anatomic boundaries, such as fascia, which may help search the source; however if the air pressure exceeds the strength of the tissues, or the time between the aggression and the imaging is too long, the air/gas is almost everywhere, which may hinder its cause. Good knowledge of the anatomic spaces and how they connect between them facilitates the quick detection of the cause. Teaching points • Ectopic air can be depicted on conventional radiographs; but CT is more sensitive and accurate • Visceral and retropharyngeal spaces directly communicate with mediastinum • Renal fascia is a single multilaminated structure, which contains potential space.
呼吸道外的气/气体会出现异常；根据其位置，通常被称为肺气肿，是指组织中滞留的气/气，或异位气/气。它可能与多种疾病相关，虽然通常是无害的，但应提示寻找潜在病因，因为一些病因需要紧急治疗。在极少数情况下，根据受累部位和演变速度，它本身可能是危及生命的情况。异常气/气超出内脏和浆膜间隙，沿某些解剖边界到达其位置，例如筋膜，这有助于寻找源头；但是如果气压超过组织强度，或者侵袭和成像之间的时间过长，气/气几乎无处不在，这可能会阻碍病因的确定。良好的解剖间隙知识以及它们之间的连接方式有助于快速发现病因。教学要点 • 异位气可在常规 X 线片上显示；但 CT 更敏感和准确 • 内脏和咽后间隙直接与纵隔相通 • 肾筋膜是一种单一的多层结构，包含潜在间隙。
