Idris Diallo, Presenter: Grant, Guerbet SA

Mathieu Auffret, Abstract Co-Author: Nothing to Disclose

Julien Ognard MD, MSc, Abstract Co-Author: Nothing to Disclose

Lakdar Attar, Abstract Co-Author: Nothing to Disclose

Elise Bouvard, Abstract Co-Author: Nothing to Disclose

Jean Rousset, Abstract Co-Author: Nothing to Disclose

Douraied Ben Salem MD, PhD, Abstract Co-Author: Nothing to Disclose

Gunshot injuries, resulting in retained bullets are frequent incidents. It is therefore crucial to evaluate the risks involved with performing magnetic resonance imaging (MRI), for patients with retained ferromagnetic objects. Furthermore, post-mortem MRI is now quite common and a retained ferromagnetic bullet can be problematic. In addition, most of the prior studies are focusing on civilian bullets and small caliber bullets. The objective of this study is to assess the magnetic field interactions at 1.5- and 3-Tesla (T) for a representative sample of military and law enforcement ballistic objects.

Twenty-nine different bullets from different manufacturers underwent MRI evaluation regarding translational attraction and torque. The deflecting angle method and a qualitative torque scale were used in the 1.5- and 3-T magnetic resonance (MR) systems. The samples were representative of those commonly used in the North Atlantic Treaty Organization (NATO) military forces (e.g. 5.56mm NATO), law enforcement agencies (e.g. 9mm Parabellum) and encountered in war injuries and crime-related trauma (e.g. 7.62mm Kalashnikov).

At all static magnetic field strengths, all non-nickel- and non-steel-containing bullets exhibited no movement. Whereas eight bullets containing steel core, steel jacket or nickel jacket exhibited substantial magnetic field interactions in excess of what might be considered safe for patients. The deflection angle was equal to 90° and their torque superior to 4. 

 Military and law enforcement non-nickel- or non-steel-containing bullets appear to be safe for patients at 1.5- and 3-T whereas ballistics containing nickel and / or steel may be dangerous because of strong magnetic field interactions. If the exact bullets’ composition is known and does not contain a ferromagnetic metal, it is safe to perform the MRI examination.

It iscrucial to evaluate the risks involved with performing magnetic resonance imaging (MRI), for patients with retained ferromagnetic objects.

Diallo, I, Auffret, M, Ognard, J, Attar, L, Bouvard, E, Rousset, J, Ben Salem, D, Military/law Enforcement Bullets and MRI: Magnetic Field Interactions at 1.5- and 3-Tesla.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018321.html