Application of postmortem MRI for identification of medulla oblongata contusion as a cause of death: a case report

[Blunt force trauma in forensic radiology]

OBJECTIVE

Description of the main forensic radiological examination modalities and findings in blunt force trauma in living and deceased adults.

METHODS

Elaboration of the essential points based on the authors' own experiences and relevant literature.

RESULTS AND CONCLUSION

Injury-related consequences of blunt force are frequently observed in forensic radiological diagnostics, especially in the context of accidents and suicides, and less frequently in homicides. The method of choice for radiological imaging of blunt force in deceased persons is native postmortem computed tomography (PMCT). In principle, the radiological effects of blunt force in PMCT do not differ significantly from those in living persons. Postmortem magnetic resonance imaging (PMMRI) is very suitable for imaging blunt soft tissue injuries in the shorter postmortem interval. In the case of living individuals with the consequences of blunt force trauma, imaging is primarily indicated for clinical diagnostic reasons. Common indications are domestic violence, violence against the elderly, and disputes in public spaces. The choice of radiological examination method depends on the clinical history and symptoms, and the radiological examinations can be subjected to a forensic assessment.

Evaluating the Effects of Pulsed Electrical Stimulation on the Mechanical Behavior and Microstructure of Medulla Oblongata Tissues

The development of remote surgery hinges on comprehending the mechanical properties of the tissue at the surgical site. Understanding the mechanical behavior of the medulla oblongata tissue is instrumental for precisely determining the remote surgery implementation site. Additionally, exploring this tissue's response under electric fields can inform the creation of electrical stimulation therapy regimens. This could potentially reduce the extent of medulla oblongata tissue damage from mechanical compression. Various types of pulsed electric fields were integrated into a custom-built indentation device for this study. Experimental findings suggested that applying pulsed electric fields amplified the shear modulus of the medulla oblongata tissue. In the electric field, the elasticity and viscosity of the tissue increased. The most significant influence was noted from the low-frequency pulsed electric field, while the burst pulsed electric field had a minimal impact. At the microstructural scale, the application of an electric field led to the concentration of myelin in areas distant from the surface layer in the medulla oblongata, and the orderly structure of proteoglycans became disordered. The alterations observed in the myelin and proteoglycans under an electric field were considered to be the fundamental causes of the changes in the mechanical behavior of the medulla oblongata tissue. Moreover, cell polarization and extracellular matrix cavitation were observed, with transmission electron microscopy results pointing to laminar separation within the myelin at the ultrastructure scale. This study thoroughly explored the impact of electric field application on the mechanical behavior and microstructure of the medulla oblongata tissue, delving into the underlying mechanisms. This investigation delved into the changes and mechanisms in the mechanical behavior and microstructure of medulla oblongata tissue under the influence of electric fields. Furthermore, this study could serve as a reference for the development of electrical stimulation regimens in the central nervous system. The acquired mechanical behavior data could provide valuable baseline information to aid in the evolution of remote surgery techniques involving the medulla oblongata tissue.