Diagnosis
Cerebral venous air embolism
Findings
Axial noncontrast CT images demonstrate gas throughout the cavernous sinuses, superior ophthalmic veins and superior sagittal sinus. No gas is seen outside the venous structures.
Discussion
Gas within the cerebral venous system is an uncommon but often alarming finding on CT examinations. The finding is nearly always iatrogenic and secondary to a venous line. Trauma and severe infection may also be considered, although these etiologies are usually known clinically. Air bubbles within the veins of the upper extremity will rise into the jugular veins in an upright patient, and proceed into the intracranial venous structures. The most commonly involved intracranial venous structures include the cavernous sinus, infratemporal fossa, carotid canal, straight sinus, superior ophthalmic vein, superior sagittal sinus, region of the foramen magnum, jugular veins, and the inferior petrosal sinus.
Symptoms due to cerebral venous air emboli are rare and self-limited. No treatment is indicated, although evaluation for sources of the emboli, such as venous catheters should be performed. Gas within the cerebral venous structures is reabsorbed quickly. In this particular patient, all of the venous gas resolved at the time of a repeat CT scan 7 hours later.
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