E1276. When Air is a Red Herring: Benign Appearances of Air in Unusual Locations
  1. Julian Sison; Yale Department of Radiology & Biomedical Imaging
  2. Syed A. Jamal Bokhari; Yale Department of Radiology & Biomedical Imaging
The presence of air in numerous locations (pleural space, peritoneum, parenchyma of various organs) is a frequent cause for concern in the emergency setting. This finding can be a warning sign of life-threatening pathology, often in the context of trauma or infection, however, numerous benign conditions can also produce air in unusual locations. Awareness of these conditions is crucial to avoid unnecessary alarm and to prevent patient harm from unwarranted imaging or procedures. In our presentation, we will present numerous cases where air presented in unusual locations but was not indicative of underlying pathology. These cases are generalizable to a broad audience, but are especially useful to radiologists practicing in the emergency setting.

Educational Goals / Teaching Points
We will introduce this topic by stressing the importance of distinguishing benign emphysematous conditions from pathologic ones. Afterward, we will conduct a case-based review of benign causes of ectopic air. We will include common conditions as well as rare conditions that we have encountered in our experience. For each case, we will discuss the relevant pathophysiology and will describe the salient imaging features that can help the practicing radiologist confidently identify these conditions as benign.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Representative examples include, but are not limited to benign pneumatosis, benign intravascular air, vacuum phenomenon, translocation of air, postmastectomy collections, pseudopneumomediastinum, and air within gallstones.

Ectopic air can frequently be a harbinger of pathology, especially in the emergency setting. However, it can also act as a red herring when it is related to a benign process. In this presentation, we present numerous benign conditions that can produce air in atypical locations and provide guidance in distinguishing these appearances from true pathology. Trainees and attending radiologists alike should be aware of these pitfalls to avoid patient harm via additional unnecessary workup or procedures. Accurate interpretation of these benign conditions is also crucial to prevent unnecessary alarm to clinicians and patients.