Vascular air embolism: location, frequency, and cause on electron-beam CT studies of the chest

Radiology. 1997 Feb;202(2):459-62. doi: 10.1148/radiology.202.2.9015074.


Purpose: To determine the frequency and location of venous air emboli that occur with the use of electron-beam computed tomographic (CT) studies of the chest.

Materials and methods: Findings from 677 patients who underwent chest electron-beam CT with intravenous administration of contrast material were reviewed. Unenhanced CT studies were performed in 127 (18.8%) of these patients while the intravenous cannula was in place but before injection of contrast material.

Results: Air emboli were observed on CT studies in 79 (11.7%) of 677 patients. Emboli were small (up to three air bubbles less than 1 cm in diameter) in 70 (10.3%) patients and were moderate (more than three air bubbles or bubbles 1-2 cm in diameter) in nine (1.3%) patients. Air emboli were located in the main pulmonary artery (n = 54 [8.0%]), superior vena cava (n = 12 [1.8%]), right ventricle (n = 10 [1.5%]), subclavian or brachiocephalic vein (n = 6 [0.9%]), and right atrium (n = 5 [0.7%]). Seven patients (1.0%) had emboli in more than one location. Air emboli were depicted on unenhanced CT scans of seven (5.5%) of 127 patients. No association was found between the frequency of air embolism and injection flow, injection site, or amount or type of contrast agent.

Conclusion: Intravenous administration of contrast material may cause small to moderate-sized air emboli. Knowledge of the common locations of emboli can help radiologists distinguish them from image artifacts or paravasal air collections.

MeSH terms

  • Brachiocephalic Veins / diagnostic imaging
  • Contrast Media / administration & dosage*
  • Embolism, Air / diagnostic imaging*
  • Embolism, Air / etiology
  • Heart Ventricles / diagnostic imaging
  • Humans
  • Injections, Intravenous / adverse effects
  • Iohexol / analogs & derivatives
  • Pulmonary Artery / diagnostic imaging
  • Radiography, Thoracic*
  • Subclavian Vein / diagnostic imaging
  • Tomography, X-Ray Computed* / adverse effects
  • Triiodobenzoic Acids
  • Vena Cava, Superior / diagnostic imaging


  • Contrast Media
  • Triiodobenzoic Acids
  • Iohexol
  • iopromide
  • iopentol