Post-mortem magnetic resonance imaging with computed tomography-guided biopsy for foetuses and infants: a prospective, multicentre, cross-sectional study

Background

Post-mortem imaging has been suggested as an alternative to conventional autopsy in the prenatal and postnatal periods. Noninvasive autopsies do not provide tissue for histological examination, which may limit their clinical value, especially when infection-related morbidity and mortality are suspected.

Methods

We performed a prospective, multicentre, cross-sectional study to compare the diagnostic performance of post-mortem magnetic resonance imaging with computed tomography-guided biopsy (Virtopsy®) with that of conventional autopsy in foetuses and infants. Cases referred for conventional autopsy were eligible for enrolment. After post-mortem imaging using a computed tomography scanner and a magnetic resonance imaging unit, computed tomography-guided tissue sampling was performed. Virtopsy results were compared with conventional autopsy in determining the likely final cause of death and major pathologies. The primary outcome was the proportion of cases for which the same cause of death was determined by both methods. Secondary outcomes included the proportion of false positive and false negative major pathological lesions detected by virtopsy and the proportion of computed tomography-guided biopsies that were adequate for histological examination.

Results

Overall, 101 cases (84 fetuses, 17 infants) were included. Virtopsy and autopsy identified the same cause of death in 91 cases (90.1%, 95% CI 82.7 to 94.5). The sensitivity and specificity of virtopsy for determining the cause of death were 96.6% (95% CI 90.6 to 98.8) and 41.7% (95% CI 19.3 to 68.0), respectively. In 32 cases (31.7%, 95% CI 23.4 to 41.3), major pathological findings remained undetected by virtopsy, and in 45 cases (44.6%, 95% CI 35.2 to 54.3), abnormalities were diagnosed by virtopsy but not confirmed by autopsy. Computed tomography-guided tissue sampling was adequate for pathological comments in 506 of 956 biopsies (52.7%) and added important diagnostic value in five of 30 cases (16.1%) with an unclear cause of death before autopsy compared with postmortem imaging alone. In 19 of 20 infective deaths (95%), biopsies revealed infection-related tissue changes. Infection was confirmed by placental examination in all fetal cases.

Conclusions

Virtopsy demonstrated a high concordance with conventional autopsy for the detection of cause of death but was less accurate for the evaluation of major pathologies. Computed tomography-guided biopsy had limited additional diagnostic value.

Trial registration

ClinicalTrials.gov (NCT01888380).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03519-4.

Post mortem computed tomography meets radiomics: a case series on fractal analysis of post mortem changes in the brain

Estimating the post-mortem interval is a fundamental, albeit challenging task in forensic sciences. To this aim, forensic practitioners need to assess post-mortem changes through a plethora of different methods, most of which are inherently qualitative, thus providing broad time intervals rather than precise determinations. This challenging problem is further complicated by the influence of environmental factors, which modify the temporal dynamics of post-mortem changes, sometimes in a rather unpredictable fashion. In this context, the search for quantitative and objective descriptors of post-mortem changes is highly demanded. In this study, we used computed tomography (CT) to assess the post-mortem anatomical modifications occurring in the time interval 0-4 days after death in the brain of four corpses. Our results show that fractal analysis of CT brain slices provides a set of quantitative descriptors able to map post-mortem changes over time throughout the whole brain. Although incapable of producing a direct estimation of the PMI, these descriptors could be used in combination with other more established methods to improve the accuracy and reliability of PMI determination.

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00414-021-02593-0.

An algorithm for automatically generating gas, bone and foreign body visualizations from postmortem computed tomography data

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.

Correlation of age, sex and season with the state of human decomposition as quantified by postmortem computed tomography

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.

Role of post mortem CT (PMCT) in high energy traumatic deaths

BACKGROUND

Post Mortem Computed Tomography (PMCT) is being increasingly implemented in forensic field and could be an adjuvant to classic autopsies. In this study we evaluated the feasibility of complementation of conventional autopsy in trauma victims with PMCT.

MATERIALS AND METHODS

A total of 21 subjects, who had sustained various types of blunt high-energy trauma, were selected from the casuistry of the Section of Legal Medicine at University of Pisa: before autopsy, a PMCT examination (Toshiba Aquilion 16 CT scanner) was performed, and after the acquisition of the raw images, MPR and VR reconstructions were performed with dedicated software.

RESULTS

PMCT is more sensitive than conventional autopsy in detecting skeletal injuries, whilst autopsy constitutes the method of choice for the detection of thoracic and abdominal visceral injuries.

CONCLUSIONS

PMCT should be considered a useful tool in addition to conventional autopsy in evaluating trauma victims: it detects further bone fractures in body parts difficult to investigate during autopsy (i.e. posterior regions), facilitating the pathologist in the reconstruction of events and in determining the cause of death.

Virtopsy of a gravid Boa constrictor using computed tomography and magnetic resonance imaging

This article presents radiologic examinations of a deeply sedated Boa constrictor with boid inclusion body disease (BIBD) as an adjunction to the subsequent necropsy. This method is known as virtopsy. The Boa constrictor in the present case was gravid. Computed tomography (CT) allowed for the detailed depiction of a fetal skeleton at the rear end of the adult snake. Furthermore, tiny gas formation was detected inside the cranium of the fetus, which was deemed a radiologic sign for decomposition. Magnetic resonance imaging (MRI) delineated the soft tissue at high resolution. This article illustrates the use of CT and MRI for the examination of a gravid Boa constrictor before necropsy and demonstrates the detection of "normal" postmortem findings leading to the confirmation of fetal death in situ.

Noninvasive 7 tesla MRI of fatal craniocerebral gunshots - a glance into the future of radiologic wound ballistics

Compared to computed tomography (CT), magnetic resonance imaging (MRI) provides superior visualization of the soft tissue. Recently, the first 7 Tesla (7 T) MRI scanner was approved for clinical use, which will facilitate access to these ultra-high-field MRI scanners for noninvasive examinations and scientific studies on decedents. 7 T MRI has the potential to provide a higher signal-to-noise ratio (SNR), a characteristic that can be directly exploited to improve image quality and invest in attempts to increase resolution. Therefore, evaluating the diagnostic potential of 7 T MRI for forensic purposes, such as assessments of fatal gunshot wounds, was deemed essential. In this article, we present radiologic findings obtained for craniocerebral gunshot wounds in three decedents. The decedents were submitted to MRI examinations using a 7 T MRI scanner that has been approved for clinical use and a clinical 3 T MRI scanner for comparison. We focused on detecting tiny injuries beyond the wound tract caused by temporary cavitation, such as microbleeds. Additionally, 7 T T₂-weighted MRI highlighted a dark (hypo intense) zone beyond the permanent wound tract, which was attributed to increased amounts of paramagnetic blood components in damaged tissue. Microbleeds were also detected adjacent to the wound tract in the white matter on 7 T MRI. Based on the findings of radiologic assessments, the advantages and disadvantages of postmortem 7 T MRI compared to 3 T MRI are discussed with regard to investigations of craniocerebral gunshot wounds as well as the potential role of 7 T MRI in the future of forensic science.

The added value of postmortem magnetic resonance imaging in cases of hanging compared to postmortem computed tomography and autopsy

The purpose of this study was to evaluate the added value of postmortem magnetic resonance imaging (MRI) compared to postmortem computed tomography (CT) and autopsy in cases of fatal hanging. In addition, the study analyzed the strengths of each examination method regarding typical injuries in these cases. We investigated a cohort of 25 decedents who underwent CT, MRI and autopsy. Two radiologists assessed all MR images of the head and neck as well as the corresponding CT images. The results were compared to autopsy findings by retrospectively analyzing the autopsy reports. Postmortem MRI revealed intramuscular hemorrhages in a large number of cases, however, autopsy did not confirm all of the detected hemorrhages. CT and autopsy detected fractures in several cases, whereas MRI showed a fracture in just one single case. Other previously described vital signs and relevant findings, such as fracture-related gas bubbles, soft tissue emphysema or pneumomediastinum, were observed in only a few individual cases. MRI provided added diagnostic value in the detection of soft tissue injuries and lymph node swelling in fatal hangings. As an adjunct to autopsy, postmortem MRI may reveal additional hemorrhages, which might be missed at autopsy. Since standard MRI demonstrated low sensitivity for the detection of fractures, an additional imaging modality or autopsy is required to overcome this limitation.

Postmortem CT in Trauma: An Overview

As forensic radiology sees an exponential gain in popularity, postmortem computed tomography (PMCT) is increasingly being used in the appropriate setting, either as preautopsy guidance or as part of complementary virtual autopsy protocol. Many articles have expounded the value it adds to forensic pathology in the general setting and the appropriate technical parameters to be used for optimum benefit. We aim to put forth a concise review on the role of PMCT specifically in trauma and the pitfalls to be aware of. Reviews have shown that presumed cause of death in trauma have been proven by autopsy to be wrong in about 30% cases. Radiology applied to postmortem investigation in unnatural deaths and more specifically in trauma shares many semiotic features with emergency radiology. Therefore, in the near future, emergency radiologists might be required to integrate this type of imaging in their regular practice. Although the predominant drawbacks are time-dependent, PMCT also has some difficulty in differentiating antemortem and postmortem events. However, in many such scenarios, PMCT and autopsy play a complementary role in arriving at conclusions, and we believe understanding the benefits and role in trauma is imperative considering the expanding usage of PMCT.

The importance of Post Mortem Computed Tomography (PMCT) in the reconstruction of the bullet trajectory

INTRODUCTION

Post Mortem Computed Tomography (PMCT) and 3D reconstruction provide a powerful tool in the evaluation of the causes of death, distinguishing between those findings related to traumas and those related to post mortal changes. It has proven to be extremely useful in case of violent deaths as a support to the traditional autopsy.

AIM OF THE STUDY

The aim of the study is to prove the essential role of PMCT in the determination of the cause of death. For this purpose, we present a case of homicide where CT scans were performed before the autopsy, thus bringing to the resolution of an otherwise controversial death.

CASE PRESENTATION

A 17 years old male died from a gunshot fired by a policeman during a chase. There were some controversies in this case that brought it to the national mediatic attention. PMCT reconstructed images showed the entry point and the ballistic trajectory of the bullet, moreover, PMCT high sensitivity in the evaluation of bone lesions, made the technique diriment in the clarification of the sequence of events that brought to the death of the subject, resolving the controversies of the case. In fact, it showed that the trajectory of the bullet could have not been compatible with the victim's family thesis.

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.

[Postmortem imaging procedures : Experiences and perspectives]

Autopsies are of key importance for the understanding of the anatomy, pathophysiology and pathomorphology. In forensic medicine, the virtual autopsy is a standard instrument in autopsy practice. The advantage of postmortem imaging is the generation of a three-dimensional pre-autopsy snapshot of the body from head to toe with excellent visualization of skeletal pathologies and air inclusions. When angiography is performed, pathologies of the cardiovascular system can additionally be evaluated. The shortcomings of postmortem imaging are the low soft tissue contrast with CT imaging, the lack of haptic, olfactory and color impressions. Another limitation is the access to CT and particularly to magnetic resonance imaging (MRI) facilities and the necessary experience with the peculiarities of postmortem imaging. To date, postmortem imaging can supplement but not replace the traditional autopsy. Nevertheless, postmortem imaging adds valuable technical capabilities to the traditional autopsy. The ability to achieve valid results for the cause of death and additional diagnoses must be evaluated systematically for postmortem imaging, in particular in addition to CT or MR guided biopsies. This article gives an overview of the current state of the technology and encourages its development for application in pathology departments.

Death by hanging: a retrospective case-control investigation of the intervertebral disc vacuum phenomenon on PMCT

During hanging gravitational forces affect the spine. Intervertebral vacuum phenomenon (VP) implies that gas accumulations in the discs are caused by degeneration of the spine and trauma. It was hypothesized that VP detected on postmortem computed tomography (PMCT) has a higher incidence in hanging deaths, which can be correlated to age, degenerative spinal changes and type of hanging (complete-incomplete). Secondly, it was investigated whether the presence of Simon's bleedings is related to hanging type and VP on PMCT. A retrospective hanging case-control study of 72 cases was conducted. PMCT data were evaluated by two observers for the presence of VP and its localization within the thoracic and lumbar discs, and for any degenerative changes of the spine. Autopsy protocols were assessed for the presence of Simon's bleedings during autopsy. VP did not statistically differ among hanging and control cases but it was statistically correlated to complete hanging, increasing age and degenerative spinal changes. Centrally located VP within the discs was correlated to hanging, especially complete hanging, and younger ages, contrary to control cases that showed gas at the disc periphery. Simon's bleedings were correlated with complete hanging and centrally located VP. Centrally located VP within the discs increases the probability for complete hanging, while increasing age and degenerative changes reduce this probability. Intervertebral VP is multifactorial radiological entity. The presence of centrally located VP can indicate that hanging could be considered as an alternative mechanism of death and that great forces and loads may have affected the spine perimortem, especially with decreasing age and when Simon's bleedings are present.

Differentiation of dental restorative materials combining energy-dispersive X-ray fluorescence spectroscopy and post-mortem CT

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.

Pandora's box

Suitcases or other containers are occasionally involved in forensic investigations. If there is a suspicion that human remains are hidden inside such a container, medico-legal examinations are required. However, these containers are occasionally locked. Forced opening of a locked suitcase or container may cause damage to its contents. Additionally, the safety of the investigator has to be considered as such containers may be booby-trapped or contain other hazardous material. An overview of the contents before opening is desirable in order to avoid the possibility of encountering a Pandora's box. In forensic medicine, an established approach to examine the inside of a body before opening at autopsy is postmortem computed tomography (CT). However, there may be a reluctance to use this approach for suitcases or containers with metallic components because of the assumption that severe metal artifacts will result in inadequate images. In this article, we present a forensic case in which a CT scan of a metallic suitcase was performed in order to examine its contents. Additionally, we performed an experimental scan of a conventional safe in order to determine if CT is able to reveal the contents of such a highly radiopaque storage box.

Post-mortem computed tomography: Technical principles and recommended parameter settings for high-resolution imaging

Post-mortem computed tomography (PMCT) has become a standard procedure in many forensic institutes worldwide. However, the standard scan protocols offered by vendors are optimised for clinical radiology and its main considerations regarding computed tomography (CT), namely, radiation exposure and motion artefacts. Thus, these protocols aim at low-dose imaging and fast imaging techniques. However, these considerations are negligible in post-mortem imaging, which allows for significantly increased image quality. Therefore, the parameters have to be adjusted to achieve the best image quality. Several parameters affect the image quality differently and have to be weighed against each other to achieve the best image quality for different diagnostic interests. There are two main groups of parameters that are adjustable by the user: acquisition parameters and reconstruction parameters. Acquisition parameters have to be selected prior to scanning and affect the raw data composition. In contrast, reconstruction parameters affect the calculation of the slice stacks from the raw data. This article describes the CT principles from acquiring image data to post-processing and provides an overview of the significant parameters for increasing the image quality in PMCT. Based on the CT principles, the effects of these parameters on the contrast, noise, resolution and frequently occurring artefacts are described. This article provides a guide for the performance of PMCT in morgues, clinical facilities or private practices.

Forensic Radiology: An Update

Forensic radiology is a specialized area of medical imaging using radiological techniques to assist physicians and pathologists in matters related to the law. The forensic application of diagnostic medical radiology can be applied in many fields; the prime target of evaluation is the osseous skeleton, but soft tissues and abdominal and thoracic viscera may offer key findings. The technological progress in clinical radiology provides a lot of potential tools to forensic radiology, allowing wider fields of applications in this matter.

A new method for estimating patient body weight using CT dose modulation data

Background

Body weight (BW) is a relevant metric in emergency care. However, visual/physical methods to estimate BW are unreliable. We have developed a method for estimating BW based on effective mAs (mAs_eff) from computed tomography (CT) dose modulation.

Methods

The mAs_eff of CT examinations was correlated with the BW of 329 decedents. Linear regression analysis was used to calculate an equation for BW estimation based on the results of decedents with a postmortem interval (PMI) < 4 days (n = 240). The equation was applied to a validation group of 125 decedents. Pearson correlation and t-test statistics were used.

Results

We found an overall strong correlation between mAs_eff and BW (r = 0.931); r values ranged from 0.854 for decedents with PMI ≥ 4 days to 0.966 for those with PMI < 4 days; among the latter group, r was 0.974 for females and 0.960 for males and 0.969 in the presence and 0.966 in the absence of metallic implants (all correlations with p values < 0.001). The estimated BW was equal to 3.732 + (0.422 × mAs_eff) – (3.108 × sex index), where the sex index is 0 for males and 1 for females. The validation group showed a strong correlation (r = 0.969) between measured BW and the predicted BW, without significant differences overall (p = 0.119) as well as in female (p = 0.394) and in male decedents (p = 0.196). No outliers were observed.

Conclusions

CT dose modulation is a rapid and reliable method for BW estimation with potential use in clinical practice, in particular in emergency settings.

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.

Imaging and virtual autopsy: looking back and forward

In order to create a three-dimensional (3D) documentation of findings which can be reassessed if necessary by other experts, the research project 'Virtopsy®' was launched in the late 1990s. This project combined autopsy results with forensic imaging in the form of computed tomography, magnetic resonance tomography and 3D surface scanning. The success of this project eventually succeeded in convincing the courts in Switzerland to accept these novel methods as evidence. As opposition towards autopsies has grown over the last decades, Virtopsy also strives to find and elaborate additional methods which can answer the main forensic questions without autopsy. These methods comprise post-mortem angiography for illustration of the vascular bed and image-guided tissue and fluid sampling for histological, toxicological and microbiological examinations. Based on the promising results, post-mortem imaging, especially with 3D surface scanning, has meanwhile also been applied to living victims of assault, who have suffered patterned injuries due to bites, blows with objects, etc. In our opinion, forensic imaging is an objective method which offers the possibility for a reassessment of the findings by other experts, even after burial or cremation of the corpse, or healing of the injuries in living victims, thus leading to a greater security in court.

Informatics and Autopsy Pathology

Many health care providers believe that the autopsy is no longer relevant in high-technology medicine era. This has fueled a decline in the hospital autopsy rate. Although it seems that advanced diagnostic tests answer all clinical questions, studies repeatedly demonstrate that an autopsy uncovers as many undiagnosed conditions today as in the past. The forensic autopsy rate has also declined, although not as precipitously. Pathologists are still performing a nineteenth century autopsy procedure that remains essentially unchanged. Informatics offers several potential answers that will evolve the low-tech autopsy into the high-tech autopsy.

Computer-assisted virtual autopsy using surgical navigation techniques

OBJECTIVE; Virtual autopsy methods, such as postmortem CT and MRI, are increasingly being used in forensic medicine. Forensic investigators with little to no training in diagnostic radiology and medical laypeople such as state's attorneys often find it difficult to understand the anatomic orientation of axial postmortem CT images. We present a computer-assisted system that permits postmortem CT datasets to be quickly and intuitively resliced in real time at the body to narrow the gap between radiologic imaging and autopsy.

CONCLUSION

Our system is a potentially valuable tool for planning autopsies, showing findings to medical laypeople, and teaching CT anatomy, thus further closing the gap between radiology and forensic pathology.

Postmortem angiography in computed tomography and magnetic resonance imaging in a case of fatal hemorrhage due to an arterio-venous malformation in the brain

Autopsy is the traditional gold standard for determining the cause and manner of death in a forensic death investigation. However, postmortem imaging plays an ever-growing role in preliminary examination, even replacing conventional autopsy in some cases. This case report presents a case of massive intra-axial brain hemorrhage due to an arterio-venous malformation. The cause and manner of death were exclusively determined by postmortem radiology. Based on radiological findings, the autopsy was considered redundant and cancelled by the public prosecutor.

Forensic imaging for causal investigation of death

A 63-year-old man was found in the street after overrun by a car. Postmortem CT revealed multiple bone fractures, but surprisingly all without any relevant hemorrhage which would have been expected under such circumstances. A round radiopaque formation was found in the duodenum, which was reminiscent of ingested tablets. The toxicological analysis revealed high concentrations of zopiclone and alcohol. By combining radiologic and forensic results, zopiclone and alcohol intoxication were concluded as the cause of death, followed by a postmortem overrun accident.

CT-guided, minimally invasive, postmortem needle biopsy using the B-Rob II needle-positioning robot

CT-guided, minimally invasive needle biopsy techniques can be used to retrieve tissue or body fluid samples for histologic tissue diagnoses in forensic investigations. The purpose of this study was an evaluation of CT-guided needle-positioning robot B-Rob II. To operate under CT guidance, we adopted the B-Rob II robotic needle placement system and its workflow. The accuracy and speed of the procedure were tested on a gelatin phantom in a series of 21 biopsies. We achieved an average needle placement accuracy of 1.8 mm (±1.1 mm) using robotic assistance. The procedure required an average of 2 min 21 s. The needle placement accuracy for minimally invasive needle biopsies using the B-Rob II biopsy robot is sufficiently accurate and fast for forensic postmortem examinations of focal organ changes. Further tests will be performed to test the feasibility of the robot for performing biopsies of focal organ changes in human bodies.

Comparison of stab wound probing versus radiological stab wound channel depiction with contrast medium

BACKGROUND

Instillation of contrast medium into stab wounds has shown promising results regarding visibility and assessment of general stab direction with computed tomography. However, the accuracy of this method--and, incidentally also probing of stab wounds--has to our knowledge not previously been examined. Also the effect of bluntness of different stabbing objects on the examination of stab wounds was not considered before this study.

METHODS

Using a pocket-knife, a steak-knife, and a Phillips screwdriver, nine stab wounds each were inflicted to three pork haunches. The depths of the stab wounds were determined by probing and multislice computed tomography (MSCT) after instillation of a contrast medium (CM) and then compared to those observed by dissection, our internal "gold standard".

RESULTS

In stab wounds inflicted by knives, MSCT-CM and probing provided results which differed by roughly 10-11% from the dissection results. In screwdriver stabs MSCT-CM showed a deviation of almost 30%, probing over 33%.

DISCUSSION

MSCT-CM is a possible alternative to layer-by-layer dissection in autopsy cases of knife stab wounds. Probing, although obsolete in post-mortem examinations, is sufficiently accurate in determining the length of a stab wound of a living person. In cases of stab wounds with blunt objects such as screwdrivers, neither MSCT-CM nor probing proved to be sufficiently accurate.

CONCLUSION

MSCT-CM is a possible alternative to layer-by-layer dissection in autopsy cases of knife stab wounds. Probing, although obsolete in post-mortem examinations, is sufficiently accurate in determining the length of a stab wound of a living person. In cases of stab wounds with blunt objects such as screwdrivers, neither MSCT-CM nor probing proved to be sufficiently accurate.

To see or not to see -- ambiguous findings on post-mortem cross-sectional imaging in a case of ruptured abdominal aortic aneurysm

We present a case of a ruptured abdominal aortic aneurysm (AAA) with ambiguous accessory findings on post-mortem computed-tomography (PMCT), post-mortem magnetic resonance (PMMR) imaging, and PMCT-angiography (PMCTA) suggestive of thoracic aortic dissection. The diagnosis of ruptured AAA was confirmed by autopsy; however, there was no aortic dissection. The imaging findings that mimicked the presence of aortic dissection might have been an atypical presentation of post-mortem clotting or sedimentation. This case is an ideal example to illustrate benefits, limitations, and challenges of post-mortem cross-sectional imaging. It serves as a reminder that both, training as well as correlation of imaging findings with autopsy are fundamental to improve our understanding of radiologic findings on post-mortem cross-sectional imaging.