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Objective We evaluated the phrase “Thank God it’s Friday” (TGIF) from a forensic pathologist’s view, i.e. the correlation between the beginning and end of the week in general and Christmas Holidays in particular and the manner of death. Material and methods We retrospectively analyzed 758 consecutive autopsy cases from January 2017 to June 2019. Results There was no correlation between natural deaths and the beginning or the end of the week. One of our main findings in terms of a weekday effect was a profound increase in homicides towards the end of the week. In terms of a Christmas Holiday effect, we sadly observed a profoundly higher rate of suicide cases during Christmas Holidays compared with the rest of the year. Conclusion The TGIF phrase should be modified towards something like “Thank God, it’s Monday” (TGIM). We also should look out for our lonely and mood-susceptible fellow human beings in particular during Christmas Holidays.

The use of postmortem computed tomography in forensic medicine, in addition to conventional autopsy, is now a standard procedure in several countries. However, the large number of cases, the large amount of data, and the lack of postmortem radiology experts have pushed researchers to develop solutions that are able to automate diagnosis by applying deep learning techniques to postmortem computed tomography images. While deep learning techniques require a good understanding of image analysis and mathematical optimization, the goal of this review was to provide to the community of postmortem radiology experts the key concepts needed to assess the potential of such techniques and how they could impact their work.

Liquid chromatography coupled to high-resolution mass spectrometry (HRMS) enables data independent acquisition (DIA) and untargeted screening. However, to avoid the handling of the resulting large dataset, most laboratories in that field still use targeted screening methods, which offer good sensitivity and specificity but are limited to known compounds. The promising field of machine learning offers new possibilities such as artificial neural networks that can be trained to classify large amounts of data. In this proof of concept study, we exemplify such a machine learning approach for raw HRMS-DIA data files. We evaluated a machine learning model using training, validation, and test sets of solvent and whole blood samples containing drugs (of abuse) common in forensic toxicology. For that purpose, different platforms were used. With a feedforward neural network model architecture, a category prediction (blank sample vs. drug containing sample) was aimed for. With the applied machine learning approaches, the sensitivity and specificity, of the validation and test set, for the prediction of sample classes were in a suitable range for an actual use in a (routine) laboratory (e.g. workplace drug testing). In conclusion, this proof of concept study clearly demonstrated the huge potential of machine learning in the analysis of HRMS-DIA data.

The forensic holodeck was first introduced in 2013, using the first upcoming commercially available virtual reality gaming headsets to visualize forensic 3D reconstructions. Following the publication of this development virtual reality was introduced in case work in a variety of different ways. After 8 years of using virtual reality in a professional forensic capacity this professional practice report will show, which equipment is necessary in addition to a virtual reality setup. This mostly includes audio-visual and broadcasting technology for complete documentation of the application of virtual reality, but also some other IT equipment, which should be available for as low as 20′000 US$. Guidelines, hints and tips regarding equipment acquisition, setup and use will be provided and discussed.

Forensic postmortem case interpretation can be challenging, in particular due to postmortem redistribution (PMR) phenomena. Recent studies have shown that computed tomography (CT)-guided collection of biopsy samples using a robotic arm (virtobot) provides a valuable tool for systematic studies on time-dependent PMR. Utilizing this strategy, several cases involving opioid use such as methadone, fentanyl, tramadol, codeine, oxycodone and hydrocodone were evaluated for time-dependent concentration changes and potential redistribution mechanisms. Upon admission to the institute (t1), blood (femoral and right ventricle heart blood) and tissue biopsy samples (lung, kidney, liver, spleen, thigh muscle and adipose tissue) were collected utilizing CT-guided biopsy. Approximately 24 h later (t2; mean 28 ± 15 h), during the autopsy, samples from the same body regions were collected manually and in addition brain tissue, gastric content, urine and left ventricle heart blood. Analysis was conducted with liquid chromatography tandem mass spectrometry. Significant time-dependent methadone concentration increases in femoral blood (pB) indicate the occurrence of PMR, however, ultimately not relevant for forensic interpretation. The main metabolite of methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), showed a less significant trend for PMR. Redistribution by passive diffusion along the muscle-to-pB concentration gradient seems likely for methadone, but not for EDDP. Results for fentanyl suggest extensive PMR. Other opioids such as tramadol, codeine, hydrocodone and oxycodone showed no consistent trend for significant PMR. Overall, CT-guided biopsy sampling proved to be a valuable tool for the investigation of PMR mechanisms.

Imaging techniques are widely used for medical diagnostics. In some cases, a lack of medical practitioners who can manually analyze the images can lead to a bottleneck. Consequently, we developed a custom-made convolutional neural network (RiFNet = Rib Fracture Network) that can detect rib fractures in postmortem computed tomography. In a retrospective cohort study, we retrieved PMCT data from 195 postmortem cases with rib fractures from July 2017 to April 2018 from our database. The computed tomography data were prepared using a plugin in the commercial imaging software Syngo.via whereby the rib cage was unfolded on a single-in-plane image reformation. Out of the 195 cases, a total of 585 images were extracted and divided into two groups labeled “with” and “without” fractures. These two groups were subsequently divided into training, validation, and test datasets to assess the performance of RiFNet. In addition, we explored the possibility of applying transfer learning techniques on our dataset by choosing two independent noncommercial off-the-shelf convolutional neural network architectures (ResNet50 V2 and Inception V3) and compared the performances of those two with RiFNet. When using pre-trained convolutional neural networks, we achieved an F1 score of 0.64 with Inception V3 and an F1 score of 0.61 with ResNet50 V2. We obtained an average F1 score of 0.91 ± 0.04 with RiFNet. RiFNet is efficient in detecting rib fractures on postmortem computed tomography. Transfer learning techniques are not necessarily well adapted to make classifications in postmortem computed tomography.

At the Zurich Institute of Forensic Medicine, post-mortem computed tomography (PMCT) has an important role. During an autopsy, access to the PMCT images can be important to localize findings. We present an approach to overcome the limitations of current systems for displaying medical image data during autopsy. The presented system uses augmented reality to display DICOM image stacks with basic functionality. In addition, we report the first test of the system during autopsy.

Background: Postmortem radiology often encounters foreign bodies in the stomach: food. Rarely, this intragastric content exhibits a high radiodensity, which can be confused with intragastric pills. We hypothesized that the radiodensity of this gastric content provided information about the interval between last meal and death. Methodology: The institutional database was searched for cases with high radiodense gastric contents seen on imaging. The postmortem interval was computed, and the interval between last meal and death was estimated. In addition, a simulation of postmortem gastric digestion was conducted. Samples of pasta, rice, lentils, chicken meat and broccoli were added to a gastric juice simulate. Computed tomography scans of the samples were repeatedly conducted for 4 h. Results: In total, 11 cases were included in the study. The gastric content was carbohydrates (rice, pasta, lentils) in six cases and meat in five cases. In both the cases and the experiment, maximum radiodensity of carbohydrates (>150 HU) was higher than of meat (100–150 HU) and vegetables (~50 HU, only experimental). Intragastric radiodensity did not correlate with the postmortem interval, and was stable in the experimental simulation apart from a decrease during the first 90 min for pasta and rice, which coincided with an increase of the radiodensity of the surrounding fluid. Conclusion: A differentiation of gastric content based on radiodensity and morphology is possible. All cases with high radiodensity had a short interval from last meal to death whenever computable. The radiodensity of intragastric food postmortem appears to be independent from the postmortem interval.

Post mortem computed tomography (PMCT) can aid in localizing foreign bodies, bone fractures, and gas accumulations. The visualization of these findings play an important role in the communication of radiological findings. In this article, we present an algorithm for automated visualization of gas distributions on PMCT image data of the thorax and abdomen. The algorithm uses a combination of region growing segmentation and layering of different visualization methods to automatically generate overview images that depict radiopaque foreign bodies, bones and gas distributions in one image. The presented method was tested on 955 PMCT scans of the thorax and abdomen. The algorithm managed to generate useful images for all cases, visualizing foreign bodies as well as gas distribution. The most interesting cases are presented in this article. While this type of visualization cannot replace a real radiological analysis of the image data, it can provide a quick overview for briefings and image reports.

Evidence acquisition, interpretation and preservation are essential parts of forensic case work that make a standardized documentation process fundamental. The most commonly used method for the documentation and interpretation of superficial wounds is a combination of two modalities: two-dimensional (2D) photography for evidence preservation and real-life examination for wound analysis. As technologies continue to develop, 2D photography is being enhanced with three-dimensional (3D) documentation technology. In our study, we compared the real-life examination of superficial wounds using four different technical documentation and visualization methods.To test the different methods, a mannequin was equipped with several injury stickers, and then the different methods were applied. A total of 42 artificial injury stickers were documented in regard to orientation, form, color, size, wound borders, wound corners and suspected mechanism of injury for the injury mechanism. As the gold standard, superficial wounds were visually examined by two board-certified forensic pathologists directly on the mannequin. These results were compared to an examination using standard 2D forensic photography; 2D photography using the multicamera system Botscan©, which included predefined viewing positions all around the body; and 3D photogrammetric reconstruction based on images visualized both on screen and in a virtual reality (VR) using a head-mounted display (HMD).The results of the gold standard examination showed that the two forensic pathologists had an inter-reader agreement ranging from 69% for the orientation and 11% for the size of the wounds. A substantial portion of the direct visual documentation showed only a partial overlap, especially for the items of size and color, thereby prohibiting the statistical comparison of these two items. A forest plot analysis of the remaining six items showed no significant difference between the methods. We found that among the forensic pathologists, there was high variability regarding the vocabulary used for the description of wound morphology, which complicated the exact comparison of the two documentations of the same wound.There were no significant differences for any of the four methods compared to the gold standard, thereby challenging the role of real-life examination and 2D photography as the most reliable documentation approaches. Further studies with real injuries are necessary to support our evaluation that technical examination methods involving multicamera systems and 3D visualization for whole-body examination might be a valid alternative in future forensic documentation.

Postmortem computed tomography (PMCT) is a standard image modality used in forensic death investigations. Case- and audience-specific visualizations are vital for identifying relevant findings and communicating them appropriately. Different data types and visualization methods exist in 2D and 3D, and all of these types have specific applications. 2D visualizations are more suited for the radiological assessment of PMCT data because they allow the depiction of subtle details. 3D visualizations are better suited for creating visualizations for medical laypersons, such as state attorneys, because they maintain the anatomical context. Visualizations can be refined by using additional techniques, such as annotation or layering. Specialized methods such as 3D printing and virtual and augmented reality often require data conversion. The resulting data can also be used to combine PMCT data with other 3D data such as crime scene laser scans to create crime scene reconstructions. Knowledge of these techniques is essential for the successful handling of PMCT data in a forensic setting. In this review, we present an overview of current visualization techniques for PMCT.

Dead bodies exhibit a variable range of changes with advancing decomposition. To quantify intracorporeal gas, the radiological alteration index (RAI) has been implemented in the assessment of postmortem whole-body computed tomography. We used this RAI as a proxy for the state of decomposition. This study aimed to (I) investigate the correlation between the state of decomposition and the season in which the body was discovered; and (II) evaluate the correlations between sociodemographic factors (age, sex) and the state of decomposition, by using the RAI as a proxy for the extent of decomposition. In a retrospective study, we analyzed demographic data from all autopsy reports from the Institute of Forensic Medicine of Zurich between January 2017 to July 2019 and evaluated the radiological alteration index from postmortem whole-body computed tomography for each case. The bodies of older males showed the highest RAI. Seasonal effects had no significant influence on the RAI in our urban study population with bodies mostly being discovered indoors. Autopsy reports contain valuable data that allow interpretation for reasons beyond forensic purposes, such as sociopolitical observations.

The sampling of cerebrospinal fluid (CSF) for chemical analysis is usually performed by a freehand lumbar puncture in a routine clinical procedure, while the suboccipital region is used for postmor...

Objectives Urine sample manipulation including substitution, dilution, and chemical adulteration is a continuing challenge for workplace drug testing, abstinence control, and doping control laboratories. The simultaneous detection of sample manipulation and prohibited drugs within one single analytical measurement would be highly advantageous. Machine learning algorithms are able to learn from existing datasets and predict outcomes of new data, which are unknown to the model. Methods Authentic human urine samples were treated with pyridinium chlorochromate, potassium nitrite, hydrogen peroxide, iodine, sodium hypochlorite, and water as control. In total, 702 samples, measured with liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, were used. After retention time alignment within Progenesis QI, an artificial neural network was trained with 500 samples, each featuring 33,448 values. The feature importance was analyzed with the local interpretable model-agnostic explanations approach. Results Following 10-fold cross-validation, the mean sensitivity, specificity, positive predictive value, and negative predictive value was 88.9, 92.0, 91.9, and 89.2%, respectively. A diverse test set (n=202) containing treated and untreated urine samples could be correctly classified with an accuracy of 95.4%. In addition, 14 important features and four potential biomarkers were extracted. Conclusions With interpretable retention time aligned liquid chromatography high-resolution mass spectrometry data, a reliable machine learning model could be established that rapidly uncovers chemical urine manipulation. The incorporation of our model into routine clinical or forensic analysis allows simultaneous LC-MS analysis and sample integrity testing in one run, thus revolutionizing this field of drug testing.

Objectives The aim of this study was to measure the mediastinal-thoracic volume ratio (CTR_VOL) on PMCT as a more accurate version of traditional CTR, in order to assess the terminal positional relationship between the heart and lungs in the different causes of death with regard to age, gender, BMI, cardiomegaly, and lung expansion. Materials Two hundred fifty consecutive postmortem cases with pre-autopsy PMCT and full forensic autopsy were retrospectively evaluated. The lungs and the mediastinum were manually segmented on the PMCT data and the correspondent volumes were estimated in situ. CTR_VOL was calculated as the ratio of the mediastinal to the thoracic volume. The volume measurements were repeated by the same rater for the evaluation of the intrarater reliability. Age, gender, body weight and height, heart weight at autopsy, and cause of death were retrieved from the autopsy reports. Presence of lung expansion was radiologically evaluated in situ. Results CTR_VOL was positively associated with age and BMI but not with gender and was higher for cardiomegaly compared to normal hearts, lower for asphyxiation-related deaths compared to cardiac deaths and intoxications, and lower for cases with lung expansion. The intrarater reliability was excellent for the calculated volumes of both lungs and mediastinum. Conclusion The results of the present study support CTR_VOL as a tool to assess the relationship between the heart and lungs in situ, which differs significantly between the studied cause of death categories.

Postmortem redistribution (PMR) leads to challenges in postmortem case interpretation. Particularly antidepressants and neuroleptics are expected to undergo PMR based on their physico-chemical properties. For the current study, time- and site-dependent PMR of 20 antidepressants and neuroleptics were investigated in humans (authentic cases); five of which are discussed in detail (citalopram, mirtazapine, quetiapine, risperidone and venlafaxine) along with two metabolites (9-OH-risperidone and O-desmethylvenlafaxine). Blood [femoral (pB) and heart blood (HB)] and tissue biopsy samples (lung, kidney, liver, spleen, thigh muscle and adipose tissue) were collected upon admission to the institute utilizing a computed tomography-guided sample collection workflow (t1). Approximately 24 h later (t2; mean 23 ± 9.3 h), samples from the same body regions were collected manually. Liquid chromatography–tandem mass spectrometry was used for quantification. Most antidepressants and neuroleptics showed significant time-dependent concentration changes indicating the occurrence of PMR. For the first time, two phases of redistribution in pB for quetiapine were proposed (concentration decreases in the early postmortem phase, followed by concentration increases) and contrasting existing literature, both concentration increases and decreases in pB overtime were observed for risperidone and 9-OH-risperidone. Venlafaxine and its metabolite only showed minimal concentration changes, while citalopram exhibited a trend for concentration increases and mirtazapine for concentration decreases in pB overtime. Based on time-dependent tissue data, passive diffusion processes along the muscle-to-pB, liver-to-HB and lung-to-HB concentration gradients could be proposed along with bacterial degradation. Overall, no case interpretation had to be adjusted, which suggests that PMR changes of antidepressants and neuroleptics do not seem to be relevant for forensic case interpretation within the 24 h period that was investigated. However, limitations of the current study (e.g., temperature-controlled storage of the bodies) could have led to an underestimation of occurring postmortem changes, hence, interpretation of postmortem results should always be conducted with care, considering PMR phenomena and inter-individual variability.

In forensic medicine the use of so-called 3D printing is a niche application, whereas developments elsewhere in this field are rapidly advancing worldwide. The most common and widespread technology is fusion deposit modelling with polylactic acids (PLA). Although the equipment and materials may be relatively inexpensive and 3D printing relatively fast, the resulting end products tend to also have negative properties, such as poor durability and mechanical anisotropy, which may be an issue depending on the application. In forensic medicine, applications in the field of weapons technology and biomechanical models are realistic and 3D printing is already being used for demonstrations at court hearings and in teaching and also as a technique for building spare parts or accessories. Having a low-cost option for rapid prototyping on-site is particularly useful for the development phase. For finished 3D designs more expensive manufacturing options with a choice of materials with significantly broader mechanical or thermal properties are available. As the technology is undergoing major changes, one should carefully consider whether to enter the field oneself, buy own hardware, use a 3D printing service or seek cooperation possibly with a nearby partner.

Zusammenfassung Hintergrund Die Legalinspektion, als Schweizer Begriff für die Leichenschau im forensischen Kontext, wird entweder von einem Amts‑/Bezirksarzt oder einem an einem rechtsmedizinischen Institut angestellten Arzt durchgeführt. Durch diese unterschiedlichen Arztgruppen kommt es zwangsläufig zu einer gewissen Heterogenität der Untersuchung. Fragestellung Wir untersuchten den Einfluss von der die Legalinspektion durchführenden Arztgruppe (Amts‑/Bezirksarzt und Arzt des Rechtsmedizinischen Instituts Zürich) auf die Obduktionsdauer. Der die Obduktion durchführende Rechtsmediziner könnte in seiner äußeren Besichtigung von dem Vorwissen über die Legalinspektion, bzw. wer diese durchgeführt hat, beeinflusst sein – und abhängig davon die äußere Besichtigung der Obduktion unterschiedlich sorgfältig bzw. zeitaufwendig durchführen. Es wurden zwei Hypothesen überprüft: zum einen, dass es einen Unterschied der Obduktionsdauer abhängig von der die Legalinspektion durchführenden Arztgruppe gibt, zum anderen, dass die Obduktionszeit am kürzesten ist, wenn der die Legalinspektion und die Obduktion durchführende Arzt derselbe ist. Methodik Wir führten eine retrospektive Analyse an 892 konsekutiven Obduktionsfällen am Institut für Rechtsmedizin der Universität Zürich durch (Januar 2017 bis Juni 2019). Für jeden Fall wurden die die Legalinspektion durchführende Arztgruppe sowie die Obduktionszeit aus den archivierten Berichten erhoben. Anschließend wurden die erhobenen Variablen in Untergruppen nach Todesart miteinander verglichen (One-way-ANOVA-Tests). Ergebnisse Die Obduktionsdauer zeigte keinen signifikanten Unterschied in allen Todesartsubgruppen zwischen den die Legalinspektion durchführenden Arztgruppen. Selbst wenn Legalinspekteur und Obduzent dieselbe Person waren, unterschied sich die Obduktionszeit nicht signifikant von den anderen Arztgruppen. Somit waren beide Hypothesen zu verwerfen. Diskussion Legalinspektion und Obduktion werden als zwei unabhängige Untersuchungen wahrgenommen. Die „zweite“ äußere Besichtigung wird selbst dann nicht als redundant empfunden, wenn Obduzent und Legalinspekteur dieselbe Person sind. Unsere Ergebnisse sehen wir auch als Ausdruck einer breiten Akzeptanz und guten Implementation der Leitlinien für Legalinspektion und Obduktion mit klar definierten Anforderungen und standardisierten Abläufen. Weiterführende Studien mit der Erfassung anderer und ergänzender Parameter zur Beurteilung auch der inhaltlichen Qualität der Legalinspektion und Obduktion sind sinnvoll und notwendig.

Documenting the existence, size, position and shape of injuries is an important part of medical forensic examinations. In the photography of an injury, the documentation is limited to an approximation of size and position of the injury based on a ruler included in the image. The documentation of injuries can be improved with photogrammetry, which allows the creation of scaled 3D models of an injury that can be used to not only document and visualize the injury but also to match the injury with an injury-causing object. In this paper, the multicamera device “Botscan” was used to perform 3D whole-body documentation and measure the positions of injuries. A major advantage of 3D whole-body documentation compared to photography is that the former can be performed at a later stage of the investigation. This makes the whole-body 3D documentation of injuries an important tool for re-examination. Electronic supplementary material The online version of this article (10.1007/s12024-020-00282-9) contains supplementary material, which is available to authorized users.

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. 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. 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. 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. 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.

Cinematic rendering technique is used to generate almost photorealistic 3D reconstructions of volumetric data. The purpose of this study was to evaluate the feasibility of cinematically rendered reconstructions in routine CT examinations of ankle sprains.Cinematic rendering technique may be primarily used to deliver visual information to patients, physicians, and virtual anatomy classes. Postprocessing requires more time than traditional methods do, which can be a hindrance in clinical work.

PURPOSE Several medical textbooks state that a human heart is approximately the size of that person's fist. Stating that a heart has the size of the corpse's fist is thought to signify that the heart size is normal. We formulate two hypotheses that are tested in this article. First, we hypothesize that in cases without cardiomegaly, volumes of the hand and the heart are not significantly different. Second, we hypothesize that in cases of cardiomegaly, the heart volume statistically significantly exceeds that of the hand. MATERIALS AND METHODS We retrospectively reviewed 130 consecutive postmortem computed tomography datasets from the BLINDED starting from 01/01/2013, covering a period of approximately 3 months. Hands and hearts were segmented and their volumes estimated. We obtained the following information from the postmortem examination reports: age, sex, body length and weight, heart weight, cardiomegaly, and cause of death. RESULTS When exploring the correlation between mean hand volume and heart volume, only in the group of the females with cardiomegaly (N=8) could a positive, statistically significant correlation be ascertained (Pearson correlation coefficient 0.753, P=.031). DISCUSSION In this study, we demonstrated that the commonly used idea that a heart larger than the fist of a patient suggests cardiomegaly might be incorrect. Because this perception is commonly used in autopsy reports, it might lead to avoidable errors. Until further studies confirm this hypothesis, this informal measurement should no longer be taught or used.

As forensic science technologies progress, digital photography has become outdated for certain documentations that require exact measurements. Recording three-dimensional objects on a two-dimensional photograph leads to a potential loss of relevant information. Photogrammetry has been utilized to record persons, objects or crime scenes and prevents this loss. Photogrammetry enables accurate documentation and visualization of events or matching of injuries and injury-causing instruments. To reduce inaccuracies during photogrammetric recording, a multi camera device, Botscan by Botspot, can be used to record living persons in three-dimensional space (3D). The device can record a full body in a fraction of a second, which leads to a significant reduction of inaccuracies due to movement. Photogrammetric measurements were compared with measurements from forensic photographs to evaluate the applicability of this device for medical forensic documentation of injuries. For this purpose, a mannequin fitted with different types of artificial injuries was used as an example. The results showed that the photogrammetric measurements obtained using the software Agisoft PhotoScan were more accurate than the measurements from the forensic photographs.

This technical note describes a pump and catheter setup that is geared towards performing post mortem computed tomography angiography (PMCTA) examinations in fetal humans. With a voltage controlled very affordable immersion pump and a modified butterfly injection needle, relatively stable linear voltage flow rate relationships can be obtained across flow rates in the range of 30 to 150 ml/min. Flow rates are calculated and compared with actual measurements, whereas practical results suggest a degree of turbulence within the setup used. Practical testing with a fetal pig results in excellent vascular filling. This was subject to considerable partial volume effect, however, so using a micro computed tomography scanner for better quality scans of PMCTA for fetal humans is highly recommended.

Estimating the sex of decomposed bodies and skeletal remains of unknown individuals is one of the first steps in the identification process of a forensic anthropological examination. As postmortem computed tomography (CT) scans are becoming a more common tool in forensic casework, the classical methods would be applied on these images. In this article, we applied the method called ´Purkait's triangle´ for sex estimation on CT scans. We hypothesize that the accuracy of sex estimation will be comparable to the application on dry bones. For this study, we acquired a total of 99 cases of postmortem CT scans from routine cases at the Institute of Forensic Medicine, Zurich, Switzerland. The femora were extracted using segmentation techniques. After this Purkait's method was applied on the segmented bone. Using the equations establish by Purkait we reached an overall accuracy of 67%. Using the method on the total length measurements showed an overall accuracy of 72% additionally a cutoff point could be established using a logistic regression. Despite some limitations, the results obtained by ´Purkait's triangle´ on CT scans for sex estimation in femoral bones showed high accuracies although not as high as applied in the classical way. Further research and testing different segmentation software might improve the result. Nevertheless, we were able to calculate a new cutoff point for a modern swiss population.

The 3D volume-rendering technique (VRT) is commonly used in forensic radiology. Its main function is to explain medical findings to state attorneys, judges, or police representatives. New visualization algorithms permit the generation of almost photorealistic volume renderings of CT datasets. The objective of this study is to present and compare a variety of radiologic findings to illustrate the differences between and the advantages and limitations of the current VRT and the physically based cinematic rendering technique (CRT).Seventy volunteers were shown VRT and CRT reconstructions of 10 different cases. They were asked to mark the findings on the images and rate them in terms of realism and understandability.A total of 48 of the 70 questionnaires were returned and included in the analysis. On the basis of most of the findings presented, CRT appears to be equal or superior to VRT with respect to the realism and understandability of the visualized findings. Overall, in terms of realism, the difference between the techniques was statistically significant (p0.05). Most participants perceived the CRT findings to be more understandable than the VRT findings, but that difference was not statistically significant (p0.05).CRT, which is similar to conventional VRT, is not primarily intended for diagnostic radiologic image analysis, and therefore it should be used primarily as a tool to deliver visual information in the form of radiologic image reports. Using CRT for forensic visualization might have advantages over using VRT if conveying a high degree of visual realism is of importance. Most of the shortcomings of CRT have to do with the software being an early prototype.

Virtual reality is recently finding its way in forensic work. The required 3D data is nowadays a standard dataset available in many cases, from homicide to traffic collisions, including not only data from the scene but also of weaponry and involved persons. Current investigations use these 3D data to replicated the incident and as discussion base for forensic personal. However, modifying the scene on a 2D viewport is often cumbersome due to the loss of the third dimension. Also to perform the modifications on the scene a 3D operator is often required. Virtual reality might improve this step by its easy use and by visualising the third dimension. This publication presents a variety of tools which can be used in forensic investigations. Additionally to the tools, examples of forensic use of these tools will be presented, showing that already a small number of tools support a variety of forensic applications.

Computer-based scene reconstruction is a method for answering specific forensic questions in the context of accident or crime scenes. For the resulting 3D reconstruction, the use of virtual reality (VR) technology is a novel presentation form. For the presentation to a prosecutor, the need to put visible content into context awards special significance to the moderator, especially as in a VR presentation the head mounted display (HMD) cuts VR users off from their natural environment. We analyze use cases for the parties involved in the courtroom VR presentation and consider the author, moderator and spectator roles and their corresponding session types for creating, directing and watching the presentation. A prototype system has been implemented to allow for suitable VR interactions for the three roles. An evaluation of the system with 12 participants assuming the role of the spectator yielded positive results with regard to the user experience and utility.

Objectives: Estimating the sex of decomposed corpses and skeletal remains of unknown individuals is one of the first steps in the identification process in forensic contexts. Although various studies have considered the femur for sex estimation, the focus has primarily been on a specific single or a handful of measurements rather than the entire shape of the bone. In this article, we use statistical shape modeling (SSM) for sex estimation. We hypothesize that the accuracy of sex estimation will be improved by using the entire shape. Materials and Methods: For this study, we acquired a total of 61 femora from routine postmortem CT scans at the Institute for Forensic Medicine of the University of Zurich. The femora were extracted using segmentation technique. After building a SSM, we used the linear regression and nonlinear support vector machine technique for classification. Results: Using linear logistic regression and only the first principal component of the SSM, 76% of the femora were correctly classified by sex. Using the first five principal components, this value could be increased to 80%. Using nonlinear support vector machines and the first 20 principal components increased the rate of correctly classified femora to 87%. Discussion: Despite some limitations, the results obtained by using SSM for sex estimation in femur were promising and confirm the findings of other studies. Sex estimation accuracy, however, is not significantly improved over single or multiple linear measurements. Further research might improve the sex determination process in forensic anthropology by using SSM.

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.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.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.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.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.

A major task of forensic investigations is the documentation and interpretation of evidence to reconstruct a forensically relevant incident. To accomplish this task, a scene is documented not only with photographs but also with 3D documentation technologies. The resulting 3D data are used for 3D visualization and to perform 3D reconstructions. In this article, we present an approach for using forensic 3D data in conjunction with virtual reality to perform scene walkthroughs in the context of witness or suspect interrogations. The aim is to provide a method for scene visits showing the original scene even years after the incident. These scene walkthroughs in VR can be reproduced and allow to see through the eyes of a witness by recording their behavior and actions. These recordings allow subsequent examinations and reconstruction to support the investigation and scene understanding and can be used as evidence in court.

While the visualization of gunshot injuries so far focused on solid metal density in routine forensic post mortem computed tomography (PMCT) as well as in micro-computed tomography, gunshot residue (GSR) as dispersed metal particles typically succumbs to partial volume effect. A case series of seven contact shots to the head was evaluated to determine a density range for GSR with at least three times higher likelihood than encountering bone, skin, muscle or blood. For that, a Bayesian likelihood was determined from normal distributions of the CT-densities of blood, bone, skin, muscle and GSR as identified in correlation with visual evidence. Resulting transfer functions matched ring and cone shaped GSR deposits as published elsewhere, thus representing a plausible result. Only fast and plausibly specific visualization is suitable for routine use in forensic PMCT, to allow the examination of GSR in real cases on a wider scale.

We present an approach that utilizes a 3D game controller as an input device in combination with a 3D/2D display technique to provide a more intuitive and efficient user interaction for PMCT visualization. An inexpensive off-the-shelf game controller was used as an input device that provides six degrees-of-freedom to create oblique image reconstructions and control a volume-rendering view. Two specific examples are described in which the system was valuable in presenting the critical pathology.

Three-dimensional (3D) surface documentation is well established in forensic documentation. The most common systems include laser scanners and surface scanners with optical 3D cameras. An additional documentation tool is photogrammetry. This article introduces the botscan© (botspot GmbH, Berlin, Germany) multi-camera system for the forensic markerless photogrammetric whole body 3D surface documentation of living persons in standing posture. We used the botscan© multi-camera system to document a person in 360°. The system has a modular design and works with 64 digital single-lens reflex (DSLR) cameras. The cameras were evenly distributed in a circular chamber. We generated 3D models from the photographs using the PhotoScan© (Agisoft LLC, St. Petersburg, Russia) software. Our results revealed that the botscan© and PhotoScan© produced 360° 3D models with detailed textures. The 3D models had very accurate geometries and could be scaled to full size with the help of scale bars. In conclusion, this multi-camera system provided a rapid and simple method for documenting the whole body of a person to generate 3D data with Photoscan©.

Objective Augmented reality techniques are being used in clinical medicine and have been suggested for use in forensic medicine as well. In this article, we investigate the feasibility of using a head mounted AR display for conducting virtual autopsies and for augmenting autopsy under realistic conditions. Materials and Methods For this study we used the Microsoft HoloLens (Microsoft Corp., Redmond, USA) as augmented reality device and DICOM-Viewer. We conducted this study in 2 phases with 5 participants. In phase 1, we conducted virtual autopsies on PMCT datasets using the AR device. In phase 2, participants performed 6 AR augmented autopsies. The time needed was recorded and the participants were interviewed about this new concept after each autopsy. Results In phase 1 (AR Virtopsy), all participants were able to determine the main pathology for all cases, requiring an average of 122 seconds per case. Participants who expressed that they are more comfortable with technology were usually faster. In phase 2 (AR autopsy), most interactions happened in the first half an hour of the internal examination of the autopsy, with the interactions becoming less frequent and shorter over time. Conclusion While AR headsets might not be useful to read and analyse CT images, AR headsets could help to bring image data such as PMCT into the autopsy hall. In such a scenario, this technology seems to be most useful in the first half an hour of the internal examination during autopsy.

The aim of this study was to evaluate the sensitivity of postmortem computed tomography (PMCT), postmortem magnetic resonance imaging (PMMR) and PMCT angiography (PMCTA) compared with autopsy in cases of adult death investigations. For this systematic review and meta-analysis, Embase, PubMed, Scopus, Web of Science and Medline were searched for eligible studies in October 2016; a follow-up literature search was conducted in March 2018. Studies referring to PMCT, PMCTA and/or PMMR of more than 3 cases with subsequent autopsy were included. Data were extracted from published texts in duplicate. The extracted outcomes were categorized as follows: soft tissue and organ findings, skeletal injuries, haemorrhages, abnormal gas accumulations and causes of death. The summary measure was sensitivity, if 3 or more studies were available. To combine studies, a random effects model was used. Variability and heterogeneity within the meta-analysis was assessed. Of 1053 studies, 66 were eligible, encompassing a total of 4213 individuals. For soft tissue and organ findings, there was a high pooled sensitivity with PMCTA (0.91, 95% CI 0.81–0.96), without evidence for between-study variability (Cochrane’s Q test p = 0.331, I2 = 24.5%). The pooled sensitivity of PMCT+PMMR was very high in skeletal injuries (0.97, CI 0.87–0.99), without evidence for variability (p = 0.857, I2 = 0.0%). In detecting haemorrhages, the pooled sensitivity for PMCT+PMMR was the highest (0.88, 95% CI 0.35–0.99), with strong evidence of heterogeneity (p 50%). Pooled sensitivity for the correct cause of death was the highest for PMCTA with 0.79 (95% CI 0.52–0.93), again with evidence of heterogeneity (p = 0.062, I2 > 50%). Distinct postmortem imaging modalities can achieve high sensitivities for detecting various findings and causes of death. This knowledge should lead to a reasoned use of each modality. Both forensic evidence and in-hospital medical quality would be enhanced.

International audience; PurposeThe purpose of this study was to report the feasibility of computed modelization and reconstitution of the paranasal sinuses, before and after trauma, from CT data.Materials and methodsWe modeled and reconstructed the paranasal sinuses of two patients (A and B), before and after trauma, using two different softwares (3DSlicer® and Blender®). Both patients had different numbers and locations of fractures. The 3DSlicer® software was used to create a 3D model from CT data. We then imported the 3D data into the Blender® software, to reconstruct and compare the dimensions of the paranasal sinuses before and after trauma.ResultsThe 3 fragments of patient A and the 7 fragments of patient B could be repositioned in the pre-traumatic configuration. Distance measurements proved to be similar between pre- and post-traumatic 3D volumes.ConclusionAfter simple trauma, bone facial anatomy reconstruction is manually feasible. The whole procedure could benefit from automatization through machine learning. However, this feasibility must be confirmed on more severely fractured paranasal sinuses, to consider an application in forensic identification.

The ability to accurately determine injury dimensions is an essential property of forensic documentation. The current standard for injury documentation is photography using a scale to approximate the injury dimensions in the image. The technical qualities of the photograph, such as orthogonality, depth of the field and sharpness of the desired area, are vital to obtaining a correct measurement. Adequate training of the forensic staff can reduce technical errors; nonetheless, there will always be some loss of information when visualizing an injury as a three-dimensional (3D) object on a two-dimensional (2D) photograph. The shortcomings of 2D photographs can be resolved by using 3D photogrammetry, which allows 3D documentation of persons and their injuries. A series of photographs has to be acquired and processed in photogrammetric software to create a photorealistic 3D model. In a prior study, a mannequin equipped with wound tattoos of known dimensions was documented with 3D photogrammetry using a multi-camera device. On the created 3D model, the dimensions of the injuries were then measured and compared to the dimensions approximated from standard forensic photographs. The results showed that the photogrammetric measurements in 3D are more accurate than the approximations performed with standard forensic photographs. In this subsequent study, the created 3D model was visualized and surveyed in virtual reality (VR), and the results were compared to the previous study. Our goal was to establish how accurately injuries can be measured in VR compared to the standard forensic photo documentation and photogrammetric method that is used on computer screens. We found that the measurements in VR are more accurate than the approximations from forensic photo documentation, but slightly less accurate than the photogrammetric measurements performed on a computer screen in dedicated software. In conclusion, photogrammetric software and virtual reality tools can both be used to make accurate size measurements of forensics-relevant injuries. Furthermore, 3D models can be visualized in varying ways allowing a much better understanding and review of injuries, even after the injury has healed.

Objectives Postmortem computed tomography (PMCT) usually includes the generation of great amounts of imaging data, and is often reviewed by forensic pathologists. To allow a more resource-efficient diagnosis, deep neural networks may act as a pre-scanning tool in postmortem radiology. In this study, a deep neural network to classify cases depending on the presence skull fractures on curved maximum intensity projections (CMIP). Methods Calvarial CMIPs of each 75 cases with and without documented skull fractures were retrospectively generated from our database. Then, half of the data were randomly assigned to either training or validation. In supervised training, fractures were manually marked. During validation, each image received a gradual score between 0 and 1 predicting the likelihood of showing one or more fractures. Results With a total number of 100 networks trained, the average area under the Receiver Operating Characteristic curve (AUC) was 0.895. The best performing network had an AUC of 0.965. At a classification threshold of 0.79, the network classified fracture cases correctly with a sensitivity of 91.4% and a specificity of 87.5%. Conclusion Classification based on the existence of skull fractures on CMIPs with deep learning is feasible. For the purpose of pre-scanning PMCT data, a classification threshold of 0.75 with a sensitivity of 100% can be applied. A higher number of images of validated skull fractures available will increase the performance of the network. In the future, Deep learning might enable a more resource-efficient assessment in postmortem radiology.

This case report details a sternal finding that first was reported as penetrating knife stab wound. It was one in a series of 24 otherwise relatively superficial skin stab wounds allegedly performed by a single assailant within the scope of a single attack. The effort required to penetrate the sternum with a knife appears to be considerably higher than to inflict relatively superficial skin and soft tissue penetration. This initially raised suspicion of another person contributing to the attack, or, a different weapon being used. After reviewing the clinical CT scans, we identified the combination of a preexisting sternal foramen with a marginal fracture and concluded that the sternal “penetration” was in keeping with the depth of the other 23 stab wounds. None of the injuries were lethal, the victim survived the attack. Assuming that a knife penetration fracture of a sternum and a foramen sternale are mutually exclusive constitutes an exclusive-OR fallacy (XOR fallacy).

OBJECTIVE: The purpose was to evaluate the presence of gas in the tissue adjacent to the laryngeal structures, "the gas bubble sign", in cases of hanging as a diagnostic indicator of neck trauma. METHODS: In this study, post-mortem CT (PMCT) scans and autopsies of 35 victims of hanging were examined to reveal age-dependent changes, laryngeal fracture, fracture location and the presence of gas. A matched group with cardiac arrest or intoxication was used as controls (n = 35). An autopsy was performed in each case. RESULTS: Incomplete suspension was the most common method in hanging. The thyroid horns (90.5%) were identified as the most vulnerable location for fractures. Laryngeal deformity and dislocation, which was only detected on PMCT, was observed in 57.1% and was concomitant with fractures in 83.3%. Laryngeal fractures are more common with advanced age (>40 years, 88.9%) and less common in younger subjects (

Today, post-mortem computed tomography (CT) is routinely used for forensic identification. Mobile energy-dispersive X-ray fluorescence (EDXRF) spectroscopy of a dentition is a method of identification that has the potential to be easier and cheaper than CT, although it cannot be used with every dentition. In challenging cases, combining both techniques could facilitate the process of identification and prove to be advantageous over chemical analyses. Nine dental restorative material brands were analyzed using EDXRF spectroscopy. Their differentiability was assessed by comparing each material's x-ray fluorescence spectrum and then comparing the spectra to previous research investigating differentiability in CT. To verify EDXRF's precision and accuracy, select dental specimens underwent comparative electron beam excited x-ray spectroscopy (EDS) scans, while the impact of the restorative surface area was studied by scanning a row of dental specimens with varying restorative surface areas (n = 10). EDXRF was able to differentiate all 36 possible pairs of dental filling materials; however, dual-energy CT was only able to differentiate 33 out of 36. The EDS scans showed correlating x-ray fluorescence peaks on the x-ray spectra compared to our EDXRF. In addition, the surface area showed no influence on the differentiability of the dental filling materials. EDXRF has the potential to facilitate corpse identification by differentiating and comparing restorative materials, providing more information compared to post-mortem CT alone. Despite not being able to explicitly identify a brand without a control sample or database, its fast and mobile use could accelerate daily routines or mass victim identification processes. To achieve this goal, further development of EDXRF scanners for this application and further studies evaluating the method within a specific routine need to be performed.

This forensic case presents unique postmortem imaging of a "drug mule" with fatal intoxication due to cocaine leakage on postmortem computed and magnetic resonance (MR) tomography compared with autopsy.Imaging by postmortem computed and MR tomography was performed before autopsy, histology, and toxicology were commissioned. Forensic imaging revealed 91 hyperdense, uniformly shaped body packs with signs of leakage, which was confirmed by autopsy. Postmortem MR imaging displayed the rarely described hypointense appearance of the body packs in T1- and T2-weighted sequences. Toxicology stated the dosage of cocaine intoxication as lethal.This case provides an opportunity to image internal cocaine drug containers on postmortem computed and MR tomography. The cause of death could be determined based on imaging and the radiological morphology of these packs by both imaging methods.