Department of Forensic Medicine and Imaging, Institute of Forensic Medicine, University of Zurich, Winterthurerstrasse 190/52, Zurich, 8057, Switzerland.
Department of Radiology, University of Debrecen, Nagyerdei krt. 98, Debrecen, 4032, Hungary.
J Forensic Sci. 2020 Jul;65(4):1360-1364. doi: 10.1111/1556-4029.14311. Epub 2020 Feb 27.
Postmortem magnetic resonance imaging (MRI) is rarely used for the radiologic assessment of gunshot injuries, although it has clear advantages over postmortem computed tomography (CT) with regard to the imaging of soft tissue injuries. Another benefit in using MRI is that lodged projectiles composed of nonferromagnetic material such as lead present only marginal metal artifacts compared with severe artifacts on CT. This case report presents CT and MRI findings in a case with two gunshot wounds to the neck: a perforating wound and a nonperforating wound with a lead bullet lodged in the cervical spine. The decedent underwent CT and MRI before the scheduled autopsy. A ring of radiopaque material under the dermis in the fatty tissue was identified at both entrance wounds on CT, which was indicative of contact shots. The perforating gunshot was clearly indicated on CT by bullet fragments along the wound channel through the perforated 6th cervical vertebra and the fractured cricoid cartilage at the exit wound. The second trajectory, however, was only assumed based on the presence of gunshot residues at the entrance wound and the position of the lodged bullet. The radiologic assessment was severely impeded by the metal artifacts on CT. Barely noticeable metal artifacts on MRI allowed for clear visualization of the soft tissue injuries and the ruptured medulla oblongata. Only MRI clarified the soft tissue injuries of the brainstem noninvasively, which could provide specific and graphic information on the rapidity of death and the incapacitation of the victim.
尸检磁共振成像（MRI）很少用于枪击伤的放射学评估，尽管它在软组织损伤的成像方面明显优于尸检计算机断层扫描（CT）。使用 MRI 的另一个好处是，与 CT 上的严重金属伪影相比，由非铁磁性材料（如铅）组成的嵌入弹丸仅呈现轻微的金属伪影。本病例报告介绍了一例颈部两处枪击伤的 CT 和 MRI 发现：一处贯通伤和一处非贯通伤，颈椎内有一枚铅弹嵌入。死者在预定尸检前接受了 CT 和 MRI 检查。CT 上在两个入口伤处的真皮下脂肪组织中均发现了一圈不透射线的物质，这表明是接触射击。在 CT 上，通过穿过穿孔的第 6 颈椎和出口伤处的断裂环状软骨的伤口通道中的弹片，明确显示出贯通性枪击。然而，第二个弹道仅根据入口伤处的枪击残留物和嵌入弹丸的位置进行推测。CT 上的金属伪影严重阻碍了影像学评估。MRI 上几乎察觉不到的金属伪影可以清晰地显示软组织损伤和破裂的延髓。只有 MRI 可以无创性地明确脑干的软组织损伤，从而提供有关死亡速度和受害者丧失能力的具体和直观信息。
