Objective: Small venous air emboli probably occur frequently. Our purpose was to describe the locations of small venous air emboli detected on CT scans of the head and neck and their clinical presentations.
Materials and methods: The head CT scans of 17 patients and neck CT scans of 10 patients with suspected venous air emboli were reviewed and the locations of the gas collections were recorded. The charts of these patients were reviewed to identify possible sources of these gas collections and any symptoms they may have produced.
Results: The most likely source of these gas collections was venous air emboli. The neck CT scans demonstrated gas in the inferior internal jugular vein, subclavian vein, and small anterior neck veins. The head CT scans demonstrated gas in the cavernous sinus, the frontal and temporal scalp, the infratemporal fossa, the carotid canal, the straight sinus, the superior ophthalmic vein, the superior sagittal sinus, extracranially in the region of the foramen magnum, and in a canal in the skull base for an emissary vein or the inferior petrosal sinus. Most of the intravenous lines were placed within 6 h of the scans demonstrating gas. The gas collections did not produce symptoms.
Conclusion: Asymptomatic venous air emboli can be identified in several locations in the head and neck. The time between manipulation of intravenous lines and the scan, the position of the patient, and the anatomy of the patient probably all affect the likelihood of identifying venous air emboli on CT scans.