Forensische Anthropologie im 21. Jahrhundert: Bestandsaufnahme

Handheld hyperspectral imaging as a tool for the post-mortem interval estimation of human skeletal remains

In forensic medicine, estimating human skeletal remains' post-mortem interval (PMI) can be challenging. Following death, bones undergo a series of chemical and physical transformations due to their interactions with the surrounding environment. Post-mortem changes have been assessed using various methods, but estimating the PMI of skeletal remains could still be improved. We propose a new methodology with handheld hyperspectral imaging (HSI) system based on the first results from 104 human skeletal remains with PMIs ranging between 1 day and 2000 years. To differentiate between forensic and archaeological bone material, the Convolutional Neural Network analyzed 65.000 distinct diagnostic spectra: the classification accuracy was 0.58, 0.62, 0.73, 0.81, and 0.98 for PMIs of 0 week-2 weeks, 2 weeks-6 months, 6 months-1 year, 1 year-10 years, and >100 years, respectively. In conclusion, HSI can be used in forensic medicine to distinguish bone materials >100 years old from those <10 years old with an accuracy of 98%. The model has adequate predictive performance, and handheld HSI could serve as a novel approach to objectively and accurately determine the PMI of human skeletal remains.

Application of Micro-Computed Tomography for the Estimation of the Post-Mortem Interval of Human Skeletal Remains

It is challenging to estimate the post-mortem interval (PMI) of skeletal remains within a forensic context. As a result of their interactions with the environment, bones undergo several chemical and physical changes after death. So far, multiple methods have been used to follow up on post-mortem changes. There is, however, no definitive way to estimate the PMI of skeletal remains. This research aimed to propose a methodology capable of estimating the PMI using micro-computed tomography measurements of 104 human skeletal remains with PMIs between one day and 2000 years. The present study indicates that micro-computed tomography could be considered an objective and precise method of PMI evaluation in forensic medicine. The measured parameters show a significant difference regarding the PMI for Cort Porosity p < 0.001, BV/TV p > 0.001, Mean1 p > 0.001 and Mean2 p > 0.005. Using a machine learning approach, the neural network showed an accuracy of 99% for distinguishing between samples with a PMI of less than 100 years and archaeological samples.

Post-Mortem Interval of Human Skeletal Remains Estimated with Handheld NIR Spectrometry

Estimating the post-mortem interval (PMI) of human skeletal remains is a critical issue of forensic analysis, with important limitations such as sample preparation and practicability. In this work, NIR spectroscopy (NIRONE® Sensor X; Spectral Engines, 61449, Germany) was applied to estimate the PMI of 104 human bone samples between 1 day and 2000 years. Reflectance data were repeatedly collected from eight independent spectrometers between 1950 and 1550 nm with a spectral resolution of 14 nm and a step size of 2 nm, each from the external and internal bone. An Artificial Neural Network was used to analyze the 66,560 distinct diagnostic spectra, and clearly distinguished between forensic and archaeological bone material: the classification accuracies for PMIs of 0−2 weeks, 2 weeks−6 months, 6 months−1 year, 1 year−10 years, and >100 years were 0.90, 0.94, 0.94, 0.93, and 1.00, respectively. PMI of archaeological bones could be determined with an accuracy of 100%, demonstrating the adequate predictive performance of the model. Applying a handheld NIR spectrometer to estimate the PMI of human skeletal remains is rapid and extends the repertoire of forensic analyses as a distinct, novel approach.

Assessment of renal glomerulosclerosis and thickness of the carotid intima-media complex as a means of age estimation in Western European bodies

INTRODUCTION

The estimation of age-at-death of unidentified cadavers is a central aspect of the identification process. With increasing age, the incidence of glomerulosclerosis and the thickness of the carotid wall have been observed to also increase. This correlation has been demonstrated in various international histological studies. The aim of our study was to assess whether these correlations also apply to a Western European population.

METHODOLOGY

In this retrospective observational study, kidney and common carotid artery samples from 216 cases autopsied at the Institute of Legal Medicine at the Justus-Liebig University in Giessen, Germany, were examined. Only cases with available tissue samples from both body sides were included. Exclusion criteria were poor sample quality and an age younger than 21 years. After histological processing, the tissue samples were assessed and digitally evaluated. Regression and classification analyses were used to investigate the correlation between age-at-death and intima-media thickness and age-at-death and the incidence of renal glomerular sclerosis.

RESULTS

Of the 216 autopsy cases, 183 were included for evaluation. Analysis of the carotid artery segments showed a strong correlation (Pearson correlation coefficient r = 0.887) between the intima-media-complex thickness and chronological age. Classification of the glomerulosclerotic incidence showed a correlation of 37.7-43.1% with the predicted age group.

DISCUSSION

Both the intima-media thickness and the proportion of sclerotic glomeruli can be used to estimate age in Western European cadavers. On the basis of these results, both methods are suited to supplement other already established methods for age-at-death estimation in the identification of an unknown cadaver.

„Skelettfund“ im Keller

Bei der Identifizierung einer unbekannten, stark verwesten Leiche oder eines Skelettes ohne Hinweise auf die Identität durch die Auffindesituation spielt die Erstellung des sog. biologischen Profils eine entscheidende Rolle. Vorgestellt wird ein Leichenfund in einem mehr oder weniger frei zugänglichen Kellerabteil eines Mehrfamilienhauses. Der Leichnam war weitgehend skelettiert, das Skelett jedoch durch mumifizierte Weichteilreste noch nahezu vollständig zusammengehalten. Bei den Hinweisen auf die Identität ergaben sich insbesondere in der Altersschätzung scheinbare Widersprüche, die jedoch zufällig eine relativ genau zutreffende Schätzung lieferten. Die Überreste konnten mittels forensischer DNA-Analyse einer seit 4 Jahren vermissten 49-Jährigen zugeordnet werden. Als Todesursache wurde ein Kältetod diskutiert.

Der Fall wies eine außergewöhnliche Auffindesituation auf, die an Bilder von „Skelettfunden“ in Kriminalverfilmungen erinnerte. Derartige Befunde dürften jedoch in der Realität wohl nur sehr selten vorkommen. Darüber hinaus werden die Wichtigkeit und die Probleme der forensisch-osteologischen Untersuchungen bei der Identifizierung eines stark verwesten, unbekannten Leichnams demonstriert.

Bony injuries in homicide cases (1994-2014). A retrospective study

Even when human skeletal remains are found in contexts indicative of body disposal after homicide, none of the bones may manifest injuries. When skeletons are incomplete, there are two possibilities, the injured bones are missing or none were injured. This leads to the question how frequently bones are injured during homicide, where the injuries tend to be placed, and whether the frequency of injury is related to the type of homicide. To answer these questions, the postmortem reports from all autopsies performed for homicide victims at the Institute of Legal Medicine at the University Hospital in Frankfurt am Main, Germany, between 1994 and 2014, were retrospectively evaluated for bony injuries discovered during autopsy. In 90 cases, a preliminary postmortem computed tomography (pmCT) examination had been performed. The cases were categorized into the following five groups by type of fatal trauma: blunt force, sharp force, gunshot injury, strangulation, or other. In total, the postmortem reports for 897 homicides (527 male, 370 female) were evaluated. The number of victims per trauma category were sharp force, 309; blunt force, 179; gunshot injury, 242; strangulation, 92; and other, 75. Bony injuries had been reported in 70.9 % of the homicides. The "gunshot" category contained the highest proportion of victims with bony injuries (92.6 %). With 80.4 %, the second-highest proportion of victims with bony injuries was in the "blunt force" category, followed by 66.3 % of victims in the "sharp force" group. In contrast, with 53.3 %, the second-lowest proportion of victims with bony injuries was in the "strangulation" category, which contained a preponderance of female victims, followed by 17.3 % of victims with bony injuries in the "other" category. Bony injuries thus occurred in the majority of homicides. Forensic osteological analysis should, therefore, always be performed on badly decomposed human remains. Where necessary, the additional use of visualization techniques, in particular, pmCT, or maceration may be considered. The absence of bony injuries does not rule out homicide; e.g., in strangulations, bony injuries are manifest in only half the victims, even when the skeleton is intact. The relevant structures are also easily lost to decomposition, scavenging, or scattering.

Post-mortem interval estimation of human skeletal remains by micro-computed tomography, mid-infrared microscopic imaging and energy dispersive X-ray mapping

In this study different state-of-the-art visualization methods such as micro-computed tomography (micro-CT), mid-infrared (MIR) microscopic imaging and energy dispersive X-ray (EDS) mapping were evaluated to study human skeletal remains for the determination of the post-mortem interval (PMI). PMI specific features were identified and visualized by overlaying molecular imaging data and morphological tissue structures generated by radiological techniques and microscopic images gained from confocal microscopy (Infinite Focus (IFM)). In this way, a more distinct picture concerning processes during the PMI as well as a more realistic approximation of the PMI were achieved. It could be demonstrated that the gained result in combination with multivariate data analysis can be used to predict the Ca/C ratio and bone volume (BV) over total volume (TV) for PMI estimation. Statistical limitation of this study is the small sample size, and future work will be based on more specimens to develop a screening tool for PMI based on the outcome of this multidimensional approach.