Communicating 3D data—interactive 3D PDF documents for expert reports and scientific publications in the field of forensic medicine

Introduction: Modern forensic investigations increasingly revert to 3D imaging techniques, such as computed tomography, magnetic resonance imaging, and 3D surface imaging. Findings are therefore often based on 3D data sets; however, this information is commonly reported and communicated within 2D imagery. The use of interactive 3D PDFs is already established in the scientific community but has yet to be implemented in the field of forensic medicine. Methods and materials: Three example cases were chosen to serve as exemplary data for the most commonly applied imaging techniques in postmortem imaging. 3D surface models were created from postmortem magnetic resonance imaging (PMMR), postmortem computed tomography (PMCT), and 3D surface imaging data sets. Results: PMMR revealed a space-occupying subdural hemorrhage that led to ipsilateral compression of the brain tissue of the right hemisphere. PMCT displayed a defect in the skull on the left side of the temporal bone. 3D surface imaging data displayed a patterned discoloration on the inside of the left forearm. Discussion: Interactive 3D PDFs offer the possibility to communicate 3D information to the reader while maintaining all the benefits of a regular 2D PDF. With Adobe Acrobat, the reader can interactively navigate through 3D data sets and create sufficient depth cues to generate a realistic 3D perception of the data. Conclusion: The interactive 3D PDF is a useful extension of standard 2D PDFs and has the potential to communicate 3D data to the reader in a more complete, more comprehensible, and less subjective manner than 2D PDFs

Papilledema as a diagnostic sign of cerebral edema on postmortem magnetic resonance imaging

The purpose of this study was to investigate papilledema (PA) as a diagnostic criterion for the presence of antemortem or agonal cerebral edema despite normal postmortem brain swelling on postmortem magnetic resonance imaging (PMMR) in comparison with conventional autopsy. One hundred subjects with head PMMR and autopsy were included in this study. The sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and accuracies were calculated in terms of the PA, PMMR, and cerebral edema on autopsy. Spearman r tests were used to analyze the linear correlations of PA and the radiological and autoptic determination of cerebral edema. In autopsy, the sensitivity regarding the presence of PA and cerebral edema was 66.2% (PPV, 70.5%), and specificity was 48.6% (NPV, 28.3%), with an overall accuracy of 60%. On PMMR, the sensitivity was 86.6% (PPV, 95%). The specificity was 90.9% (NPV, 34%), with an overall accuracy of 88%. The Spearman correlation revealed a statistically significant result (P < 0.001), which indicated a strong linear correlation of the presence of PA and cerebral edema with the autopsy results and the PMMR results. The presence of PA may aid in the diagnoses of cerebral edema despite normal postmortem brain swelling based on PMMR

Deep Into the Fibers! Postmortem Diffusion Tensor Imaging in Forensic Radiology.

PURPOSE In traumatic brain injury, diffusion-weighted and diffusion tensor imaging of the brain are essential techniques for determining the pathology sustained and the outcome. Postmortem cross-sectional imaging is an established adjunct to forensic autopsy in death investigation. The purpose of this prospective study was to evaluate postmortem diffusion tensor imaging in forensics for its feasibility, influencing factors and correlation to the cause of death compared with autopsy. METHODS Postmortem computed tomography, magnetic resonance imaging, and diffusion tensor imaging with fiber tracking were performed in 10 deceased subjects. The Likert scale grading of colored fractional anisotropy maps was correlated to the body temperature and intracranial pathology to assess the diagnostic feasibility of postmortem diffusion tensor imaging and fiber tracking. RESULTS Optimal fiber tracking (>15,000 fiber tracts) was achieved with a body temperature at 10°C. Likert scale grading showed no linear correlation (P > 0.7) to fiber tract counts. No statistically significant correlation between total fiber count and postmortem interval could be observed (P = 0.122). Postmortem diffusion tensor imaging and fiber tracking allowed for radiological diagnosis in cases with shearing injuries but was impaired in cases with pneumencephalon and intracerebral mass hemorrhage. CONCLUSIONS Postmortem diffusion tensor imaging with fiber tracking provides an exceptional in situ insight "deep into the fibers" of the brain with diagnostic benefit in traumatic brain injury and axonal injuries in the assessment of the underlying cause of death, considering influencing factors for optimal imaging technique