A carotid artery vascular clamp is a medical device that is surgically placed around the carotid artery and is used to temporarily block blood flow through the carotid artery in order to treat a brain (cerebral) aneurysm.

To date, each carotid artery vascular clamp tested in association with a 1.5-Tesla MR system displayed positive magnetic field interactions. However, only the Poppen-Blaylock carotid artery vascular clamp is considered contraindicated for patients undergoing MR procedures due to the existence of substantial ferromagnetism. The other carotid artery clamps were considered safe for patients exposed to MR systems because they were deemed "weakly" ferromagnetic. With the exception of the Poppen-Blaylock clamp, patients with the other carotid artery vascular clamps that have been evaluated for magnetic field interactions have been imaged by MR systems with static magnetic fields up to 1.5-Tesla without experiencing discomfort or neurological issues.

REFERENCES
Shellock FG, Crues JV, Editors. MRI Bioeffects, Safety, and Patient Management. Biomedical Research Publishing Group, Los Angeles, CA, 2014.

Shellock FG, Kanal E. Magnetic Resonance: Bioeffects, Safety, and Patient Management. Second Edition, Lippincott-Raven Press, New York, 1996.

Teitelbaum GP, Lin MCW, Watanabe AT, et al. Ferromagnetism and MR imaging: safety of carotid vascular clamps. AJNR Am J Neuroradiol 1990;11:267-272.