Whole Brain CT Perfusion after Cerebral Air Embolism

Computer tomography perfusion patterns in iatrogenic cerebral arterial gas embolism: A retrospective cohort study

PURPOSE

Cerebral arterial gas embolism (CAGE) occurs when air or medical gas enters the systemic circulation during invasive procedures and lodges in the cerebral vasculature. Non-contrast computer tomography (CT) may not always show intracerebral gas. CT perfusion (CTP) might be a useful adjunct for diagnosing CAGE in these patients.

METHODS

This is a retrospective single-center cohort study. We included patients who were diagnosed with iatrogenic CAGE and underwent CTP within 24 h after onset of symptoms between January 2016 and October 2022. All imaging studies were evaluated by two independent radiologists. CTP studies were scored semi-quantitatively for perfusion abnormalities (normal, minimal, moderate, severe) in the following parameters: cerebral blood flow, cerebral blood volume, time-to-drain and time-to-maximum.

RESULTS

Among 27 patient admitted with iatrogenic CAGE, 15 patients underwent CTP within the designated timeframe and were included for imaging analysis. CTP showed perfusion deficits in all patients except one. The affected areas on CTP scans were in general located bilaterally and frontoparietally. The typical pattern of CTP abnormalities in these areas was hypoperfusion with an increased time-to-drain and time-to-maximum, and a corresponding minimal decrease in cerebral blood flow. Cerebral blood volume was mostly unaffected.

CONCLUSION

CTP may show specific perfusion defects in patients with a clinical diagnosis of CAGE. This suggests that CTP may be supportive in diagnosing CAGE in cases where no intracerebral gas is seen on non-contrast CT.

Unusual Cerebral Emboli

The heart and the carotid arteries are the most common sites of origin of embolic disease to the brain. Clots arising from these locations are the most common types of brain emboli. Less common cerebral emboli include air, fat, calcium, infected vegetations, and tumor cells as well as emboli originating in the venous system. Although infarcts can be the final result of any type of embolism, described herein are the ancillary and sometimes unique imaging features of less common types of cerebral emboli that may allow for a specific diagnosis to be made or at least suspected in many patients.

Hyperintensity in the subarachnoid space on contrast-enhanced fluid-attenuated inversion-recovery magnetic resonance imaging after central venous catheter removal

Cerebral air embolism is a rare complication of central venous catheterization. A 61-year-old man developed a left-sided hemiparesis immediately after his right jugular venous catheter removal. A diffusion-weighted magnetic resonance imaging (MRI) obtained 2 h after the symptom onset was normal. However, postgadolinium cerebral spinal fluid enhancement was seen on fluid-attenuated inversion-recovery MRI. A repeat diffusion-weighted MRI, 18 h later, showed restricted diffusion in the bilateral hemispheres. Disruption of the blood-brain barrier caused by the air bubbles might lead to accumulation of gadolinium in the subarachnoid space. Postgadolinium cerebral spinal fluid enhancement may be an early, sensitive predictor of blood-brain barrier disruption and impending cerebral infarct after air embolism.