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Emergency Radiology

E2758. An Imaging Guide to Evaluating Orbital Trauma

Mohandas A,  Daruwalla V,  Abdelhadi S,  Haider M,  Shah K. Detroit Medical Center, Wayne State University, Detroit, MI

Address correspondence to A. Mohandas (aravind.utd@gmail.com)

Background Information: Approximately 3% of visits to the emergency room (ER) are due to trauma to the eye. The incidence of blindness following orbital trauma is reported to be 0.5–5%. Complete clinical assessment of the integrity of the orbit is difficult, particularly with respect to retro bulbar regions. Additionally, these cases are invariably associated with injuries to other parts of the body that may be distractors during clinical assessment. Therefore, imaging plays a crucial role in accurately delineating orbital injury. This exhibit aims to review the normal anatomy of the orbit and globe and discuss a methodologic approach to evaluating orbital trauma with imaging examples.

Educational Goals/Teaching Points: A comprehensive review of the normal anatomy of the orbit and globe will be provided followed by description of a systematic approach to evaluating the orbit in the setting of trauma. Key imaging points in the identification of orbital wall fracture, orbital emphysema, intraconal hemorrhage, extra ocular muscle entrapment, globe injury and optic nerve compromise will be discussed. A section will be dedicated to discussing patterns of injury based on the type and direction of trauma.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: In the emergent setting, CT is the mainstay in evaluating orbital injury. A step-wise systematic approach is required during assessment of orbital trauma. This includes scrutinizing the orbital wall for fractures and herniation of orbital contents. This is followed by evaluation of the globe, where attention needs to be paid to the anterior chamber, lens position, and posterior chamber. Hemorrhage, abnormal fluid collection, and presence of foreign body must be considered when evaluating these structures. Next, extra ocular muscles are examined, where asymmetric enlargement may be seen as a result of entrapment or hemorrhage. Assessment of the optic nerve and ophthalmic vein is then considered. Special attention must be given to the orbital apex, where subtle injuries may be missed.

Conclusion: Orbital trauma is encountered frequently in the ER with imaging playing a key role in comprehensive assessment. An extensive review of anatomy and methodology behind assessment of the orbit with the assistance of numerous imaging examples will aid in interpretation of cases with orbital trauma.