Air bubbles in the subclavian or internal jugular veins: a common finding on contrast-enhanced CT

Reduction of venous air embolism in coronary computed tomography angiography using a modified method of saline test injection

OBJECTIVES

This paper analyzed the feasibility of reducing venous air emboli introduced during tube connection in computed tomography angiography (CTA) through a modified method of saline test injection.

METHODS

A total of 386 cases of patients undergoing coronary CTA examination were randomly arranged into a control group (199 patients underwent conventional saline injection before the CTA examination) and a case group (187 patients underwent modified saline injection before the CTA examination). The two groups were compared for the location (Fisher's exact test), number (χ² test), and diameter (Mann-Whitney rank sum test) of the air emboli along the inflow direction of contrast agent within the scan.

RESULTS

The occurrence rate was 10.55% in the control group and 3.74% in the case group respectively, with a statistically different significance (P = 0.010). In the case group, there were 7 cases of small-grade venous air emboli. In the control group, there were 15 cases of small-grade venous air emboli and 6 cases of moderate-grade venous air emboli. No cases of large-grade venous air emboli were found in both groups.

CONCLUSIONS

The use of this modified method of saline test injection before CTA examination is able to effectively decrease the occurrence of venous air emboli introduced during tube connection, which has some certain practical significance.

Venous air embolism detected on computed tomography of small animals

OBJECTIVE

To describe the prevalence, location and clinical significance of abnormal gas accumulations in dogs and cats detected on computerised tomography images.

METHODS

Retrospective evaluation of all canine and feline computed tomography examinations (292 pre-contrast and 219 post-contrast) performed in a 12-month time period. All studies were evaluated for the presence of venous air emboli. The location of intravenous gas was noted and the volume of intravenous air emboli was estimated visually. The medical records of animals with venous air embolism were reviewed for signs of cardiopulmonary complications.

RESULTS

The overall prevalence of air embolism on pre- and incidence on post-contrast images was 4 · 5 and 2 · 3%, respectively. The prevalence of air embolism on pre-contrast and incidence on post-contrast thoracic images was 35 · 7 and 14 · 2%, respectively. The volume of venous air was generally small and the most common was in an axillary vein. None of the animals had any cardiopulmonary complications.

CLINICAL SIGNIFICANCE

The presence of small volume venous air embolism on routine computed tomography examinations is a frequent incidental finding that does not appear to cause cardiopulmonary complications.