The importance of Post Mortem Computed Tomography (PMCT) in the reconstruction of the bullet trajectory

Thermal bone injuries: postmortem computed tomography findings in 25 cases

INTRODUCTION

Fire death investigations attempt to determine whether a subject was alive or dead before the fire started. Therefore, it is essential to assess if the bone damage is traumatic or the result of exposure to heat. This observational study aims to expose the specific CT semiology of thermal bone lesions to allow the forensic radiologist to identify and distinguish them from traumatic lesions that would have preceded death.

MATERIALS AND METHODS

We retrospectively reviewed the CT findings of 25 bodies with thermal bone lesions for which a postmortem computed tomography (PMCT) was performed prior to an autopsy. Imaging findings were correlated to the autopsy data to identify the specific features of thermal bone lesions.

RESULTS

Specific signs of thermal injuries to bone were identified on PMCT on all deceased cases. Thermal damages predominated in areas directly exposed to flames (rib cage, distal extremities) with less soft tissue coverage ("soft tissue shielding"). The mottled appearance of bone marrow was a constant sign of burned bones. Heat fractures such as trans-diploic fractures of flat bones and beveled ("flute-mouthpiece") fractures of extremities seemed specifically related to thermal mechanism. In addition, we provided a better description of superficial cortical fissures of flat bones ("ancient Chinese porcelain") and observed a "stair step" fracture of a long bone until now undescribed in radiological literature.

CONCLUSION

Thermal bone lesions have specific CT findings, different on several points from traumatic injuries. Their knowledge is essential for radiologists and forensic physicians to provide an accurate report of injury and conclusions.

Diagnostic value and forensic relevance of a novel photorealistic 3D reconstruction technique in post-mortem CT

OBJECTIVES

Evaluation of performance and forensic relevance of a novel, photorealistic, 3D reconstruction method (cinematic rendering, (CR)) in comparison with conventional post-mortem CT (PMCT) and volume rendering (VR) technique for visualization of traumatic injuries.

METHODS

112 pathologies (fractures, soft tissue injuries and foreign bodies) from 33 human cadavers undergoing whole body PMCT after traumatic death were retrospectively analyzed. Pathologies were reconstructed with CR and VR techniques. Fractures were classified according to their dislocation. Images were evaluated according to their expressiveness and judicial relevance by two forensic pathologists using a five-level Likert-scale (1: high expressiveness, 5: low expressiveness). They decided whether CR reconstructions were suitable for judicial reviews. The detection rate of pathologies was determined by two radiologists.

RESULTS

CR was more expressive than VR for all three trauma categories (p < 0.01) and than conventional CT when used for fractures with dislocation (p < 0.001), injuries of the ventral body surface (p < 0.001), and demonstration of foreign bodies (p = 0.033). CR and VR became more expressive with a higher grade of fracture dislocation (p < 0.001). 20% of all pathologies in the CR and VR reconstructions were not detectable by radiologists.

CONCLUSION

CR reconstructions are superior to VR regarding the expressiveness. For fractures with substantial dislocation, soft tissue injuries, and foreign bodies in situ, CR showed a significantly better expressiveness than conventional PMCT. CR and VR have significant limitations in cases of fractures with minor dislocations and covered soft tissue injuries.

ADVANCES IN KNOWLEDGE

CR is a helpful tool to present pathologies found in PMCT for judicial reviews.

Debonding and Clean-Up in Orthodontics: Evaluation of Different Techniques and Micro-Morphological Aspects of the Enamel Surface

There is currently no consensus on the best way to remove adhesive remnants from teeth following debonding. The main objective of this study is to evaluate and compare the effectiveness of four adhesive resin removal (clean-up) techniques, performed with or without the use of an operative microscope. Forty human teeth were duplicated using an epoxy resin for impregnation. Brackets were bonded to teeth and debonded from teeth. Then, the samples were randomly divided into two equal groups-the naked eye group and the magnification group-and further subdivided into four equal subgroups, in order to compare the different techniques used for the clean-up. Each subgroup was formed of five natural teeth with the respective pre- and post-bonding replicas. Macro- and micro-analysis by means of a stereomicroscope and scanning electron microscopy evaluated, qualitatively and quantitatively, the adhesive remnant index and the damage index of the enamel. Overall, the magnification improved the removal of resins compared to the naked eye (p < 0.001), and the use of magnification constantly reduced resin residual and surface damage. Enamel damage and adhesive residual from the clean-up procedures represent an ascertained risk in orthodontics. The use of a magnification system improves the quality of debonding and clean-up techniques in a significant way.