Assessment of gunshot bullet injuries with the use of magnetic resonance imaging

Background: Magnetic resonance imaging (MRT) is rarely used for preoperativ e assessment of shotgun injuries because of concerns of displacing the poss ibly ferromagnetic foreign body within the surrounding tissue. Methods: A total of 56 different projectiles underwent MRT testing for ferr omagnetism and imaging quality in vitro and in pig carcasses with a commerc ially available 1.5-MRI scan. Image quality was compared with that of compu ted tomographic scans. Results: Projectiles with ferromagnetic properties can be distinguished eas ily from nonferromagnetic ones by pretesting the motion of an identical pro jectile within the MRI coil. When ferromagnetic projectiles were excluded, MRI yielded the more precise images compared with other imaging techniques. Projectile localization and associated soft tissue injuries were visualize d without artifacts in all cases. Conclusions: When ferromagnetic foreign bodies are excluded by pretesting t heir properties within the MRI with a comparative projectile, MRI portends an excellent imaging procedure for assessing the extent of injury and plann ing the removal by surgery.