Suicide is the eighth cause of mortality in France and the leading cause in people aged between 25 and 34 years. The most common methods of suicide are hanging, self-poisoning with medicines and firearms. Postmortem computed tomography (CT) is a useful adjunct to autopsy to confirm suicide and exclude other causes of death. At autopsy, fractures of the hyoid bone or thyroid cartilage, or both, are found in more than 50% of suicidal hangings. Cervical vertebra fractures are rare and only seen in suicide victims jumping from a great height. Three-dimensional reconstructions from CT data are useful to visualize the ligature mark on the neck. In suicides by firearm, postmortem CT shows entry and exit wounds, parenchymal lesions along the bullet path, as well as projectiles in case of penetrating trauma. However, in the chest and abdomen it is more difficult to identify the path of the projectile. Postmortem CT also shows specific features of suicide by drowning or stabbing, but its use is limited in cases of self-poisoning. The use of postmortem CT is also limited by decomposition and change of body position. This article presents the imaging features seen on postmortem CT according to the method of suicide.

Objectives: The goal of this ex vivo study was to determine if Dual-Energy Computed Tomography (DECT) can discriminate ferromagnetic bullets from non-ferromagnetic bullets. Methods: Twelve different bullets, placed in the center of the scanner on a gelatin phantom, underwent DECT evaluation. These projectiles were both ancient bullets from the 19Th century (eg. 8mm 1890 ECP) and recent bullets from the late 20th century (eg. 9mm Lüger; 7.92mm Mauser; 7mm sport carabin). Two independent radiologists who were blinded to the properties of bullets performed all measurement on an external workstation with extended CT scale. Regions of interest (ROI) were placed in the core of each projectile. From these data, a dual-energy index (DEI) was calculated. A bootstrap method with a p value of less than 0.05 was used to demote statistical significance. Results: Five bullets were ferromagnetic and seven were non-ferromagnetic. The DEI calculated were significantly (p<0.05) different between the ferromagnetic and nonferromagnetic projectiles. There were no significant difference (p>0.05) for intrareader and interreader agreement analysis. Conclusion: Dual-energy CT, despite several limitations, could be a valid method to differentiate ferromagnetic from non-ferromagnetic bullets in an ex-vivo environment with extended CT-scale. This approach could contribute to MR safety but further studies are necessary before using dual-energy CT as a routine technique for screening gunshots victims.

Objective The aim was to determine if dual-energy computed tomography (DECT) can discriminate ferromagnetic bullets from nonferromagnetic ones. Methods The ferromagnetic properties of 29 bullets were determined. All bullets underwent a DECT evaluation, and a manual measurement of the dual-energy index was performed by 2 radiologists, followed by a fully automatic measurement, in 3 different positions in a phantom (air, water, and bone). Results Twenty-one bullets were found to be nonferromagnetic. There were significant differences between the mean of the dual-energy index measured in the core of ferromagnetic projectiles and those of nonferromagnetic ones in the lung position of the phantom (P = 0.007). Specificity was 86.36%, and negative predictive value was 90.48%. Among the 29 bullets, 24 were correctly classified. Conclusions Our study demonstrates that DECT can assess the ferromagnetic status of bullets and their magnetic resonance imaging compatibility using an extended computed tomography scale in an ex vivo phantom model.

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