Magnetic resonance imaging in lumbar gunshot wounds: an absolute contraindication?

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Performance of MR imaging in patients with gunshot wounds at or near the lumbar spinal canal is controversial. The authors reviewed the literature on the use of MR imaging in gunshot wounds to the spine. They discuss the results from in vitro and clinical studies, analyze the physical properties of common projectiles, and evaluate the safety and indications for MR imaging when metallic fragments are located near the spinal canal.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>A review of the English-language literature was performed. Data from 25 articles were analyzed, including 5 in vitro studies of the interaction between 95 projectiles and the MR system's magnetic fields, and the clinical outcomes in 22 patients with metallic fragments at or near the spinal canal who underwent MR imaging.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Properties of 95 civilian and military projectiles were analyzed at a magnet strength of 1, 1.5, 3, and 7 T. The most common projectiles were bullets with a core of lead, either with a copper jacket or unjacketed (73 [76.8%] of 95). Steel-containing (core or jacket) projectiles comprised 14.7%. No field interaction was evident in 78 (96.3%) of the 81 nonsteel projectiles. All steel projectiles showed at least positive deflection forces, longitudinal migration, or rotation. Heating of the projectiles was clinically insignificant. Image artifact was significant in all 9 steel bullets tested, but was not significant in 39 (88.6%) of the 44 nonsteel bullets tested. Overall, 22 patients with complete (82%) and incomplete (14%) spinal cord injury secondary to a projectile lodged inside the spinal canal underwent MR imaging. Discomfort and further physical or neurological deficits were not reported by any patient. Two patients with spinal cord injuries underwent MR imaging studies before surgical decompression and had subsequent, significant neurological improvement.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Metallic implants near or at the spinal canal are a relative contraindication for MR imaging. However, safe MR imaging might be feasible when a projectile's properties and a patient's individualized clinical presentation are considered.</jats:p></jats:sec>

Civilian Gun Shot Wounds Associated With Spinal Injuries

“…However, several studies have demonstrated that non-nickel and non-steel based bullets are safe to undergo MRI. 13 - 15 Venous lead levels are routinely drawn on GSW patients in order to obtain baseline values. If spinal instability is present, bracing is offered or surgical intervention consisting of instrumentation and fusion with removal of bullet fragment if encountered.…”

Intracranial bullet removal using O-arm navigation guidance

“…retained bullets from firearm injuries or fragments of missiles/bomb shells. The ferromagnetic metal objects can rotate and/or move in a magnetic field and thus possibly result in secondary damage [2,3,11].…”

Role of Whole-Body Computed Tomography Scan to Avoid Missed Foreign Body in Patients with Multiple Stab Injury: A Rare Case of Retained Impaled Knife Blade with Intact Neurology

“…MRI was deferred due to the presence of the metallic object. 2,3 The decision was made to conservatively manage her renal injury. She was planned for wound exploration and FB removal under general anesthesia.…”