Can postmortem MRI be used to assess trajectories in gunshot victims?

• Published in: International journal of legal medicine Vol. 130; no. 2; pp. 457 - 462
• Main Authors: Luijten, M., Haest, I. I. H., van Kan, R. A. T., van Lohuizen, W., Kroll, J., Schnerr, R. S., Hermsen, R., Hofman, P. A. M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2016; Springer Nature B.V
• Subjects: Electrons; Forensic Ballistics - methods; Forensic Medicine; Gelatin; Humans; Magnetic fields; Magnetic Resonance Imaging; Medical Law; Medicine; Medicine & Public Health; Models, Biological; Multidetector Computed Tomography; Original; Original Article; Phantoms, Imaging; Radiology; Scanners; Tomography; Victims of crime; Viscosity; Wounds, Gunshot - diagnostic imaging; Netherlands; Forensic radiology; Postmortem imaging; MR imaging; Safety; Projectile; Gunshot
• ISSN: 0937-9827; 1437-1596; 1437-1596
• DOI: 10.1007/s00414-015-1273-4

Purpose Multi-detector computed tomography (MDCT) has proven to be of value for the reconstruction of trajectories of projectiles and the assessment of the injuries in deceased gunshot victim. For the depiction of soft tissue injury, MRI is superior to MDCT and MRI may be of value to assess trajectories. In a clinical setting, there are guidelines for the application of MRI in patients with projectiles or projectile fragments and with precautions MRI is safe for these patients. However, this has not been studied for the postmortem application of MRI from a forensic point of view. Subjects and method To assess the behaviour of projectiles, two ferromagnetic and one non-ferromagnetic projectile were exposed to the magnetic field of a 1.5- and 3-T MRI. Projectiles were placed in six phantoms with the characteristics of human muscle tissue, with and without a simulated trajectory in the gel. Before and after exposure to the magnetic field, the gelatine phantoms were imaged with MDCT to assess the position of the projectiles. Results The ferromagnetic projectiles rotate to a position where their long axis is parallel to the z -axis of the magnetic field and five out of the six projectiles moved through, either through the simulated trajectory or through a new trajectory. This was observed in both the 1.5- and 3-T systems. Conclusion Ferromagnetic projectiles can rotate and migrate in a gelatine phantom. It is very likely that these projectiles will also migrate in a human body in a MRI system. Therefore, from a forensic point of view, postmortem MR will make a reconstruction of the trajectories in the body and of the reconstruction of the incident as a whole less reliable.