How low can we go? CT dose reduction in the assessment of the medial clavicular epiphysis in forensic age estimation: a prospective postmortem CT study.

BACKGROUND: Projection radiography and, more recently, computed tomography (CT) play an important role in forensic age estimation. Both in terms of general criminal responsibility and government regulations concerning refugee care, it is important to differentiate correctly between youths and adults. A disadvantage of age estimation in CT is the ionizing radiation exposure. PURPOSE: To investigate how far the CT dose can be reduced without losing diagnostic confidence in assessing the different stages of ossification of the medial clavicle. MATERIAL AND METHODS: We prospectively scanned 25 postmortem cases with a fixed parameters protocol (FPP) and a care dose modulation protocol (CDMP) for different scan parameters. Two radiologists assessed the diagnostic image quality using a 5-point Likert scale. Inter-reader agreement was evaluated with Cohen's kappa. Differences in doses between FPP and CDMP were assessed with the one-tailed t-test. RESULTS: The best combination of diagnostic image quality and lowest radiation dose was obtained using a CDMP with 100 kV and 40 mAs and an FPP with 100 kV and 30 mAs. Doses for 120 kV were significantly higher (one-tailed P < 0.001). The diagnostic image quality for 80 kV was insufficient overall. DISCUSSION: Our results confirm that CT imaging at 100 kV allows a sufficient image quality that is diagnostic for age estimation in the ossification of the medial clavicle.

Gunshot wounds to the head: a comparison of postmortem magnetic resonance imaging, computed tomography, and autopsy.

BACKGROUND: Postmortem imaging has become a powerful diagnostic tool in forensics. Postmortem computed tomography (PMCT) is often used currently to complement and sometimes even replace an autopsy. PURPOSE: To compare PMCT, postmortem magnetic resonance imaging (PMMRI), and autopsy findings for gunshot wounds to the head. MATERIAL AND METHODS: Cross-sectional study. We performed a retrospective analysis of 24 cases with gunshot wounds to the head that underwent both PMCT and PMMRI between 2011 and 2018 at the Institute of Forensic Medicine, University of Zurich (Switzerland). RESULTS: Our study confirms that PMCT and, to a slightly lesser degree, PMMRI provide additional information that is valuable when combined with autopsy findings. Air embolism was solely detected in PMCT (67% vs. 0% at autopsy). A retained bullet or projectile and bone fragments were diagnosed more frequently with PMCT (42%, 67%, and 92%) than at autopsy (33%, 42%, and 46%). Soft tissue lesions were more often detected with PMMRI than with PMCT. With regard to autopsy, subdural hemorrhage and ventricular hemorrhage were slightly more frequently diagnosed with PMMRI (63% and 75% vs. 38% and 58% at autopsy). Intracerebral hemorrhage was by far most often diagnosed with PMMRI (92%) compared with both PMCT (38%) and autopsy (14%). CONCLUSION: All three modalities should ideally be considered in cases of craniocerebral gunshot wounds. However, it might be conceivable that depending on the forensic query, PMCT and PMMRI may be an adequate replacement for an autopsy.

Potentials of post-mortem CT investigations during SARS-COV-2 pandemic: a narrative review.

In December 2019, a new coronavirus, SARS-COV-2, caused a cluster of cases of pneumonia in China, and rapidly spread across the globe. It was declared a pandemic by the World Health Organization on March 11th, 2020. Virtual autopsy by post-mortem CT (PMCT) and its ancillary techniques are currently applied in post-mortem examinations as minimally or non-invasive techniques with promising results. In this narrative review, we speculate on the potentials of PMCT and its ancillary techniques, as a viable investigation technique for analysis of suspected or confirmed SARS-COV-2 deaths. An online literature search was performed by using three prefix search terms (postmortem, post-mortem, post mortem) individually combined with the suffix radiology, imaging, computed tomography, CT and with the search terms 'SARS-CoV-2' and 'COVID-19' to identify papers about PMCT and its ancillary techniques in SARS-COV-2 positive cadavers. PMCT findings suggestive for pulmonary COVID-19 in deceased positive SARS-COV-2 infection are reported in the literature. PMCT ancillary techniques were never applied in such cases. PMCT imaging of the lungs has been proposed as a pre-autopsy screening method for SARS-COV-2 infection. Further studies are needed to ascertain the value of PMCT in determining COVID-19 as the cause of death without autopsy histopathological confirmation. We advocate the application of PMCT techniques in the study of ascertained or suspected SARS-COV-2 infected deceased individuals as a screening technique and as a method of post-mortem investigation, to augment the numbers of case examined and significantly reducing infection risk for the operators.

RiFNet: Automated rib fracture detection in postmortem computed tomography.

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.

Diagnostic accuracy of postmortem computed tomography for bleeding source determination in cases with hemoperitoneum.

AIM: The aim of this retrospective study was to determine the accuracy of postmortem computed tomography and different radiological signs for the determination of the bleeding source in cases with hemoperitoneum confirmed at autopsy. METHODS: Postmortem computed tomography data of consecutive cases with hemoperitoneum confirmed at autopsy were reviewed by two raters, blinded to the autopsy findings. The determination of possible bleeding sources was based on the presence of the sentinel clot sign, blood or sedimented blood surrounding an organ, intraparenchymal abnormal gas distribution, and parenchymal disruption. The bleeding source and the cause of hemoperitoneum (traumatic, surgical, natural, or resuscitation) as reported in the autopsy report were noted. The survival intervals of the deceased were calculated when information about the time of an incident related to death was available in the autopsy reports. RESULTS: Eighty-five cases were included in the study. Postmortem computed tomography showed 79% sensitivity and 92.1% specificity for the detection of the bleeding source. The sentinel clot sign was associated with surgical or natural causes of hemoperitoneum and longer survival intervals. Sedimented blood around the bleeding source was associated with resuscitation. Abnormal gas distribution within organs and combination of multiple radiological signs provided higher sensitivity. CONCLUSION: Postmortem computed tomography provides moderate sensitivity and high specificity for determining the bleeding source in cases with hemoperitoneum. Different PMCT signs are associated with different causes of hemoperitoneum and survival intervals.

Evaluation of the mediastinal-thoracic volume ratio on postmortem computed tomography.

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.

Comparison of superficial wound documentation using 2D forensic photography, 3D photogrammetry, Botscan© and VR with real-life examination.

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 imaging findings and cause of death determination compared with autopsy: a systematic review of diagnostic test accuracy and meta-analysis.

BACKGROUND: 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. METHODS: 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. RESULTS: 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 < 0.05, I2 > 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%). CONCLUSION: 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.

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.

Cardiac conduction devices in the radiologic comparative identification of decedents.

Cardiac conduction devices (CCDs), including pacemakers and implantable cardioverter-defibrillators (ICDs), are implanted in a significant part of the population, especially as the population becomes older. CCDs play an important role in forensic medicine; they are a valuable identification tool as the manufacturer information and unique serial numbers of the device can be matched with the medical records of the person of suspected identity after the device has been removed from the body. Radiological examinations such as X-ray or computed tomography (CT) can illustrate specific CCD features. A series of 12 selected cases is presented to highlight the ability of postmortem CT to visualize CCD details, contributing to possible comparative radiological identification in the case of suspected identity without the requirement of invasive removal. To date, unique patient-specific serial numbers, which are usually not radiopaque, cannot be visualized by imaging. However, a positive match of specific CCD radiologic features combined with other peculiar body findings between ante- and postmortem images can lead to a pure radiologic comparative identification.

Potential use of deep learning techniques for postmortem imaging.

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.

Approaching pulmonary fat embolism on postmortem computed tomography.

PURPOSE: Pulmonary fat embolism (PFE) is a relevant diagnosis playing a role as a sign of vitality or a cause of death. Its severity is assessed according to histological grading systems like that of Falzi. The aim of this study was to determine the utility of unenhanced postmortem computed tomography (PMCT) for PFE diagnosis based on the detection of fat layers. METHODS: Consecutive cases with PMCT and autopsy were studied retrospectively. The case group consisted of cases with positive PFE, and the control group included cases with negative PFE. Three observers independently assessed PMCT data for fat layers in the pulmonary trunk and the right and left pulmonary artery. For cases with fat layers, autopsy protocols were assessed for the cause of death, relation to trauma, and undertaken resuscitation measures. RESULTS: Eight hundred thirty cases were included: 366 PFE positive cases (144 of Falzi grade 1, 63 of 1.5, 99 of 2, 28 of 2.5, and 32 of 3) and 464 PFE negative cases. Interrater reliabilities varied between substantial and almost perfect, and discrepancies were solved according to majority. Eighteen cases showed fat layers on PMCT (2 controls-traumatic instantaneous deaths-, 16 PFE positive cases). PMCT showed low sensitivity but high specificity for PFE diagnosis. The layers were located at the same position in the pulmonary trunk directly adjacent to the pulmonary valve distal to the right ventricle. CONCLUSION: Fat layer on PMCT is a rare finding but relates to PFE diagnosis, especially of severe histological grade. It is to be expected in a typical position within the pulmonary trunk.

Nasal Septum Defects Detected on Postmortem Computed Tomography.

Nasal septum defects may have forensic relevance because they are associated with various mechanisms, including trauma and cocaine abuse. Like all human body tissues, the nasal septum may be affected by maggots' infestation during postmortem decomposition. Postmortem computed tomography (PMCT) can reveal small findings and related details. Three cases of early postmortem period and 2 cases of advanced decomposition, where external examination of the nasal cavities and PMCT revealed nasal septum defect, are presented. In the early postmortem period cases, the lesions' edges appeared smoother on PMCT, whereas in the advanced decomposed cases, the edges were irregular and maggots were infested. Postmortem computed tomography can detect nasal septum defects and may help differentiate the preexisting from the postmortem ones based on their edges' radiological appearance. Such findings may indicate possible chronic cocaine abuse (cocaine nose), trauma, or other nasal pathology. It is important to note that such defects may be altered or caused by advanced decomposition.

Fatal Road Traffic Vehicle Collisions With Pedestrian Victims: Forensic Postmortem Computed Tomography and Autopsy Correlation.

Fatal car-to-pedestrian collisions regularly appear in the forensic pathologist's routine, particularly in places of extended urbanization. Postmortem computed tomography has gained an exceptional role to supplement autopsy worldwide, giving information that is supplementary or complimentary to conventional autopsy. In this retrospective study, a total number of 320 findings in a series of 21 pedestrians fatally hit by cars and trucks of both postmortem computed tomography and autopsy were correlated. According to our results, it is best to combine both methods to give well-founded answers to questions pertaining to both collision reconstruction and cause of death.

Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study.

OBJECTIVE: 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). MATERIALS AND METHODS: 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. RESULTS: 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 (p < 0.05). Most participants perceived the CRT findings to be more understandable than the VRT findings, but that difference was not statistically significant (p > 0.05). CONCLUSION: 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.

Role of Survival Time and Injury Severity in Fatal Pulmonary Fat Embolism.

Pulmonary fat embolism (PFE) is frequent in blunt trauma and may occasionally lead to death. A correlation between fracture grade and severity and PFE grade has been described before, but no correlation between PFE and survival time, fat crushing extent, fat crush grade, or number of body regions with fractures could be noted in this small study. To further examine this, we decided to examine the aforementioned points in a far larger study group.Autopsy protocols of 188 nonresuscitated fatalities with blunt trauma and without right heart injury, which underwent whole body dissection, were retrospectively reviewed concerning the presence and the severity of PFE, injuries, survival time, age, sex, and the body mass index.The fracture grade, the fracture severity, and the number of the fractured regions correlated very well with the grade of PFE, but the crushed regions, crush grade, and crush severity did not. We observed a time correlation between survival time and PFE only in the sense that very rapid deaths were often PFE negative. High-grade PFE was observed most often in patients having died less than 6 hours after the incident, and PFE grades of 2 or more were occasionally noted even after 48 hours.

VirtoScan - a mobile, low-cost photogrammetry setup for fast post-mortem 3D full-body documentations in x-ray computed tomography and autopsy suites.

Injuries such as bite marks or boot prints can leave distinct patterns on the body's surface and can be used for 3D reconstructions. Although various systems for 3D surface imaging have been introduced in the forensic field, most techniques are both cost-intensive and time-consuming. In this article, we present the VirtoScan, a mobile, multi-camera rig based on close-range photogrammetry. The system can be integrated into automated PMCT scanning procedures or used manually together with lifting carts, autopsy tables and examination couch. The VirtoScan is based on a moveable frame that carries 7 digital single-lens reflex cameras. A remote control is attached to each camera and allows the simultaneous triggering of the shutter release of all cameras. Data acquisition in combination with the PMCT scanning procedures took 3:34 min for the 3D surface documentation of one side of the body compared to 20:20 min of acquisition time when using our in-house standard. A surface model comparison between the high resolution output from our in-house standard and a high resolution model from the multi-camera rig showed a mean surface deviation of 0.36 mm for the whole body scan and 0.13 mm for a second comparison of a detailed section of the scan. The use of the multi-camera rig reduces the acquisition time for whole-body surface documentations in medico-legal examinations and provides a low-cost 3D surface scanning alternative for forensic investigations.

Automatic detection of hemorrhagic pericardial effusion on PMCT using deep learning - a feasibility study.

Post mortem computed tomography (PMCT) can be used as a triage tool to better identify cases with a possibly non-natural cause of death, especially when high caseloads make it impossible to perform autopsies on all cases. Substantial data can be generated by modern medical scanners, especially in a forensic setting where the entire body is documented at high resolution. A solution for the resulting issues could be the use of deep learning techniques for automatic analysis of radiological images. In this article, we wanted to test the feasibility of such methods for forensic imaging by hypothesizing that deep learning methods can detect and segment a hemopericardium in PMCT. For deep learning image analysis software, we used the ViDi Suite 2.0. We retrospectively selected 28 cases with, and 24 cases without, hemopericardium. Based on these data, we trained two separate deep learning networks. The first one classified images into hemopericardium/not hemopericardium, and the second one segmented the blood content. We randomly selected 50% of the data for training and 50% for validation. This process was repeated 20 times. The best performing classification network classified all cases of hemopericardium from the validation images correctly with only a few false positives. The best performing segmentation network would tend to underestimate the amount of blood in the pericardium, which is the case for most networks. This is the first study that shows that deep learning has potential for automated image analysis of radiological images in forensic medicine.

Accuracy of non-contrast PMCT for determining cause of death.

The aim of this study was (1) to compare levels of accuracy regarding the categorization of causes of death between non-contrast post-mortem computed tomography (PMCT) and the final forensic report as well as between autopsy and the final forensic report, and (2) to assess levels of confidence regarding the categorization of causes of death after non-contrast PMCT and after autopsy. This prospective study was conducted over a 5 month period during which 221 cases were admitted to our institute for forensic investigations. Whole-body PMCT and forensic autopsy were performed in every case. Of these, 101 cases were included in the final study population. Inclusion criteria were: (1) age > 18 years, (2) presence of at least one of the two principal investigators at the time of admission. One radiologist and one forensic pathologist independently read all PMCT datasets using a report template. Cause of death category and confidence levels were determined by consensus. Forensic autopsy was performed by two forensic pathologists; both unblinded to imaging results. Both post-imaging and post-autopsy cause of death categorization were compared against the final cause of death, as stated in the forensic expert report, which included findings from histology and/or toxicology. Accuracy of post-imaging cause of death categorization in reference to the final cause of death category was substantial (82%, 83/101 cases, Kappa 0.752). Accuracy of post-autopsy cause of death categorization in reference to the final cause of death category was near perfect (89%, 90/101 cases, Kappa 0.852). Post-imaging sensitivity and specificity regarding the categorization of causes of death were 82% and 97%, respectively. Post-autopsy sensitivity and specificity regarding the categorization of causes of death were 89% and 98%, respectively. There was a high consistency between the accuracy of post-imaging cause of death categorization and post-imaging levels of confidence. There was less consistency between accuracy of post-autopsy cause of death categorization and post-autopsy levels of confidence. In this study categorization of causes of death based on non-contrast enhanced PMCT alone, and on PMCT and macroscopic autopsy together, proved to be consistent with the final cause of death-category as determined based on all available information including PMCT, autopsy, and (if available) histology and/or toxicology in more than 82% and 89% of all cases, respectively. There was higher consistency between levels of confidence and accuracy of causes of death categorization was higher post-imaging than post-autopsy. These results underline the fact that the diagnostic potential of PMCT goes beyond the assessment of trauma cases.

Differentiation of hemopericardium due to ruptured myocardial infarction or aortic dissection on unenhanced postmortem computed tomography.

The aim of the study was to evaluate unenhanced postmortem computed tomography (PMCT) in cases of non-traumatic hemopericardium by establishing the sensitivity, specificity and accuracy of diagnostic criteria for the differentiation between aortic dissection and myocardial wall rupture due to infarction. Twenty six cases were identified as suitable for evaluation, of which ruptured aortic dissection could be identified as the underlying cause of hemopericardium in 50% of the cases, and myocardial wall rupture also in 50% of the cases. All cases underwent a PMCT and 24 of the cases also underwent one or more additional examinations: a subsequent autopsy, or a postmortem magnetic resonance (PMMR), or a PMCT angiography (PMCTA), or combinations of the above. Two radiologists evaluated the PMCT images and classified each case as "aortic dissection", "myocardial wall rupture" or "undetermined". Quantification of the pericardial blood was carried out using segmentation techniques. 17 of 26 cases were correctly identified, either as aortic dissections or myocardial ruptures, by both readers. 7 of 13 myocardial wall ruptures were identified by both readers, whereas both readers identified correctly 10 of 13 aortic dissection cases. Taking into account the responses of both readers, specificity was 100% for both causes of hemopericardium and sensitivity as well as accuracy was higher for aortic dissections than myocardial wall ruptures (72.7% and 87.5% vs 53.8% and 75% respectively). Pericardial blood volumes were constantly higher in the aortic dissection group, but a statistical significance of these differences could not be proven, since the small count of cases did not allow for statistical tests. This study showed that diagnostic criteria for the differentiation between ruptured aortic dissection and myocardial wall rupture due to infarction are highly specific and accurate.