Comparison of findings identified at traditional invasive autopsy and postmortem computed tomography in suicidal hangings.

Cases of suicidal hanging are a common death referred for medico-legal autopsy throughout the world. Although some advocate using postmortem computed tomography (PMCT) without traditional invasive autopsy (TIA) to investigate such deaths, others reject this approach. There is currently limited evidence to guide practice. In this context, the TIA reports and PMCT images of 50 cases of suspected suicidal hanging during an 11-month period were reviewed. The reviewers were blinded to the findings of the other modality. A Cohen's Kappa coefficient (K) was calculated to assess agreement between TIA and PMCT across a range of pertinent findings. This analysis demonstrated perfect agreement for identification of a ligature (K = 1.00) and a strong level of agreement for identification of a ligature suspension point (K = 0.832) but only a minimal level of agreement for overall ligature mark (K = 0.223). PMCT demonstrated a weak level of agreement for fractures of hyoid bone (K = 0.555) and thyroid cartilage (K = 0.538). Three probable fractures not identified at TIA were identified on PMCT. TIA was shown to be superior in the identification of intramuscular and laryngeal fracture-related haemorrhage/bruising whereas PMCT was superior to TIA in identifying body gas deposition. There was overall good correlation between the natural disease and trauma identified elsewhere in the body during the TIA and PMCT. The study demonstrates that PMCT can assist the investigation of suspected suicidal hangings. However, the accuracy of many findings is limited, and if it is used as an alternative to the TIA, potentially pertinent findings, such as fractures of the laryngeal cartilages, could be missed.

Axonal injury is detected by ßAPP immunohistochemistry in rapid death from head injury following road traffic collision.

The accumulation of ßAPP caused by axonal injury is an active energy-dependent process thought to require blood circulation; therefore, it is closely related to the post-injury survival time. Currently, the earliest reported time at which axonal injury can be detected in post-mortem traumatic brain injury (TBI) tissue by ßAPP (Beta Amyloid Precursor Protein) immunohistochemistry is 35 min. The aim of this study is to investigate whether ßAPP staining for axonal injury can be detected in patients who died rapidly after TBI in road traffic collision (RTC), in a period of less than 30 min.We retrospectively studied thirty-seven patients (group 1) died very rapidly at the scene; evidenced by forensic assessment of injuries short survival, four patients died after a survival period of between 31 min and 12 h (group 2) and eight patients between 2 and 31 days (group 3). The brains were comprehensively examined and sampled at the time of the autopsy, and ßAPP immunohistochemistry carried out on sections from a number of brain areas.ßAPP immunoreactivity was demonstrated in 35/37 brains in group 1, albeit with a low frequency and in a variable pattern, and with more intensity and frequency in all brains of group 2 and 7/8 brains from group 3, compared with no similar ßAPP immunoreactivity in the control group. The results suggest axonal injury can be detected in those who died rapidly after RTC in a period of less than 30 min, which can help in the diagnosis of severe TBI with short survival time.

Autopsy assessment of pediatric head injury: a proposal for aerosol mitigation during the COVID-19 pandemic.

During the Corona Virus Disease-19 (COVID-19) pandemic, there is still a requirement for post-mortems to continue, including those examinations performed in the context of medico-legal investigations. Currently, very little is known about how long this coronavirus can survive in deceased human bodies or whether un-embalmed human cadavers can be contagious to people who handle them. Therefore, it would appear to be prudent to consider implementation of additional safety measures for all necessary post-mortem procedures. During the post-mortem examination of babies and young children, it is important to open the calvarium to enable visualization of the brain and its coverings, particularly in cases where a head injury is likely to have occurred. Since October 2013, the use of neurosurgical equipment to open the calvarium during infant and young child autopsies has become routine practice in our unit. Both the neurosurgical craniotome and a standard oscillating mortuary saw produce particulate matter consisting of bone and body fluids (including blood) which can become aerosolized. Within this paper, we discuss the use of a transparent plastic tent whilst opening the calvarium during pediatric post-mortems, to reduce the spread of aerosols into the mortuary environment.

A look inside cardiopulmonary resuscitation: A 4D computed tomography model of simulated closed chest compression. A proof of concept.

AIM: To mimic chest compression during cardiopulmonary resuscitation (CPR), this study aimed to produce time-resolved 3D (volumetric) reformats of thoracic and upper abdominal tissue movement during incremental closed chest compression/decompression from 0 to 8 to 0 cm. METHODS: Sequential angiography enhanced computed tomography (CT) scans were acquired from a recently deceased, consented adult cadaver with 1 cm incremental closed chest compression/decompression. Three compression/decompression sequences from 0 to 3 cm, 0 to 5 cm, and 0 to 8 cm, respectively, were scanned using a radio-opaque, manually operated, chest compression device. The multiphase volumetric data sets were compiled into 4D models that allowed for multiplanar reformatted and volume rendered image manipulation. RESULTS: Time-resolved volumetric (4D) models were produced using freeware to post-process the static CT scans. The 4D models allowed the study of simulated thoracic and upper abdominal content movement during closed chest compression. CONCLUSIONS: The method described could assist CPR researchers and educators in the development and demonstration of effective CPR protocols.

Postmortem Computed Tomography: An Overview for Forensic Nurses Involved in Death Investigation.

The traditional invasive autopsy has been considered the "gold standard" for death investigation worldwide. However, this has now been challenged by a new minimally invasive approach that utilizes cross-sectional radiological imaging to investigate the death. Globally, postmortem computed tomography is the most commonly used modality and is becoming increasingly available throughout the world. Forensic nurses working in association with coroners and medical examiners' offices, as well as mass fatality incidents, now need to update their knowledge base to understand these innovative techniques, the advantages and disadvantages to their use, and how they impact on medicolegal death investigation and the care of the deceased and bereaved. Using the example of the coroner system of England and Wales, this article provides a comparison between the traditional invasive autopsy and postmortem radiological alternatives and presents the impact postmortem radiology is now having on death investigation.

Remote post-mortem radiology reporting in disaster victim identification: experience gained in the 2017 Grenfell Tower disaster.

On 14 June 2017 at 00:54 h, the worst residential fire since the conclusion of the Second World War broke out in Flat 16, 4th floor of the 24-storey residential Grenfell Tower Block of flats, North Kensington, West London, UK. Seventy-one adults and children died, including one stillbirth. All victims of the Grenfell Tower disaster who died at the scene underwent post-mortem computed tomography (PMCT) imaging using a mortuary-sited mobile computed tomography scanner. For the first time, to the authors' knowledge, the disaster victim identification (DVI) radiology reporting was undertaken remote to the mortuary scanning. Over an 11-week period, 119 scans were undertaken on 16 days, with up to 18 scans a day. These were delivered to a remote reporting centre at Leicester on 13 days with between 2 and 20 scans arriving each day. Using a disaster-specific process pathway, a team of 4 reporters, with 3 support staff members, trialled a prototype INTERPOL DVI radiology reporting form and produced full radiology reports and supporting image datasets such that they were able to provide 96% of prototype DVI forms, 99% of image datasets and 86% of preliminary reports to the DVI teams in London within one working day of image receipt. This paper describes the first use of remote radiology reporting for DVI and exemplifies how remote PMCT reporting can be used to support a DVI process of this scale.

Myocardial Infarction Due to Coronary Artery Injury following High Force Blunt Trauma to the Upper Chest: A Case Illustrating the Prehospital, Hospital and Autopsy Findings.

Myocardial infarction (MI) is a rare complication of blunt chest trauma (BCT). We describe an extensive antero-lateral MI due to thrombosis of the left main stem coronary artery following a blow to the lower face and upper anterior chest during an industrial accident in a 52-year-old male. The patient presented with acute left ventricular failure. Our case highlights MI as an important differential in a BCT patient presenting with hypoxia where lung pathology has been excluded. We aim to highlight the importance of cardiac assessment in trauma scenarios particularly where patients are unable to report symptoms. Our patient sadly did not survive his injuries. This case describes MI following BCT from the initial prehospital presentation through to postmortem findings and adds to the limited literature on the pathological mechanisms underpinning this rare complication.

Using freely-available 3D software to reconstruct traumatic bone injuries detected with post mortem computed tomography.

Use of post-mortem computed tomography (PMCT) scanning to investigate natural and unnatural death has increased dramatically in recent years. Powerful software exists to allow detailed analysis of the scanned anatomy and pathology, and users of PMCT and other medical imaging will already be familiar with both two-dimensional and three-dimensional (3D) representations of this data. However, standard medical image viewing programs do not allow direct manipulation of the visible anatomy. By extracting anatomical features from medical images, this data can be exported into 3D manipulation software to enhance pathological examination and anatomical demonstration. Here we illustrate, using an example of lower limb fractures from a pedestrian road traffic fatality, that open source software (Blender) can be used not only to manipulate the anatomical data, but to produce high-quality images and animations that are superior to what is achievable using the available output of standard medical image viewers. The described software provides practitioners from many different disciplines an ability to manipulate medical imaging data that may previously have seemed too expensive or otherwise inaccessible. The potential applications for this technique are not limited to trauma analysis, and the purpose of this document is to encourage others to explore this powerful software and its abilities. The article contains many specific terms, and targeted online searches using this vocabulary will reveal an abundance of guidance and video tutorials that will help even the complete novice begin to undertake apparently sophisticated 3D software tasks with relative ease and at no additional cost.

How taphonomic alteration affects the detection and imaging of striations in stab wounds.

Stabbing with a kitchen knife is a common method of homicide in Europe. Serrated knives may leave tool markings (striations) in tissues. Documentation of striations is necessary for their use as forensic evidence. Traditional methods (physical casting and photography) have significant limitations, and micro-computed tomography (micro-CT) has been trialled in cartilage to "virtually cast" wounds. Previous research has shown the proportion of striations in cartilage falls following decomposition. This project has investigated the effects of taphonomic alteration and documentation methods of striations in porcine skin. Fresh, decomposed, mummified, burnt and waterlogged stab wounds in a porcine analogue were excised and imaged using photography, stereo-optical microscopy and micro-CT. The proportion of striations in each taphonomic group was determined from the images by independent analysts. Striations were observed more frequently in serrated blade wounds, although they were also identified in non-serrated blade wounds. The proportion of wounds showing striations declined following decomposition. An inversely proportional linear correlation between advancing decomposition and proportion of striations existed. Dehydration (mummification and burning) rendered serrated and non-serrated blade wounds indistinguishable. Water composition affected the preservation of striations. Identification of striations gradually declined after decomposition in tap water, but persisted to a point when left in brackish water. All three techniques imaged striations; however, the optimum technique was stereo-optical microscopy due to practical advantages and specific limitations affecting photography and micro-CT. This study demonstrates the effects of taphonomic alteration on striations and suggests stereo-optical microscopy is the optimum method for their documentation.

Forces generated in stabbing attacks: an evaluation of the utility of the mild, moderate and severe scale.

The commonest way of killing in the UK is by a sharp instrument. Knight reported in 1975 that it is impossible to discern with any degree of certainty the degree of force used to create a stab wound. Despite this, expert witnesses continue to approximate the degree of force used for their reports and evidence in court. It is usually subjectively categorized as mild, moderate or severe, based solely on the examination of the wound. We undertook a study considering forces generated in a range of blunt trauma actions, using a novel force plate dynamometer to measure the peak forces obtained by adult male and female volunteers. We then studied forces generated by stabbing skin simulants and porcine samples with knives and screwdrivers. Men generated more force than women during stabbings which was found to be equivalent to somewhere between the blunt trauma actions of pushing a button to a single-handed push. When asked to stab using what they thought was mild, moderate and severe force, although volunteers were able to actively decide the force used, the actual force was found to be influenced by the weapon, sex of the individual, hand used and biological/anatomical site penetrated. This study shows that the forces generated by volunteers in mild, moderate and severe stabbing tests in almost all cases were significantly greater than the forces required for skin penetration. We suggest that the use of subjective force scales is inappropriate. Rather than use of a subjective scale, we suggest that the force required in any stabbing requires investigation in four areas: the tip radius of the weapon, minimal force required for penetration, the sex of the assailant and whether the force required for penetration is greater than that that can be generated by a person stabbing. This allows for the use of an evidence-based two-tier scale to suggest the force required.

A systematic autopsy survey of human infant bridging veins.

In the first years of life, subdural haemorrhage (SDH) within the cranial cavity can occur through accidental and non-accidental mechanisms as well as from birth-related injury. This type of bleeding is the most common finding in victims of abusive head trauma (AHT). Historically, the most frequent cause of SDHs in infancy is suggested to be traumatic damage to bridging veins traversing from the brain to the dural membrane. However, several alternative hypotheses have been suggested for the cause and origin of subdural bleeding. It has also been suggested by some that bridging veins are too large to rupture through the forces associated with AHT. To date, there have been no systematic anatomical studies on infant bridging veins. During 43 neonatal, infant and young child post-mortem examinations, we have mapped the locations and numbers of bridging veins onto a 3D model of the surface of a representative infant brain. We have also recorded the in situ diameter of 79 bridging veins from two neonatal, one infant and two young children at post-mortem examination. Large numbers of veins, both distant from and directly entering the dural venous sinuses, were discovered travelling between the brain and dural membrane, with the mean number of veins per brain being 54.1 and the largest number recorded as 94. The mean diameter of the bridging veins was 0.93 mm, with measurements ranging from 0.05 to 3.07 mm. These data demonstrate that some veins are extremely small and subjectively, and they appear to be delicate. Characterisation of infant bridging veins will contribute to the current understanding of potential vascular sources of subdural bleeding and could also be used to further develop computational models of infant head injury.

Could post-mortem computed tomography angiography inform cardiopulmonary resuscitation research?

AIM: Firstly, to develop an optimised chest compression post mortem computed tomography angiography protocol in the adult human during closed chest compression to investigate cardiopulmonary resuscitation blood flow, and secondly to provide preliminary observations of post-mortem anatomical cardiac chamber movement using a novel radiolucent static chest compression device. METHODS: Variable volumes of radiological contrast agent were injected intravenously into a series of consented human cadavers. Each cadaver had chest compressions delivered with a LUCAS™2 mechanical chest compressor. Following each cycle of chest compressions, each cadaver was imaged with a Toshiba Aquilion CXL 128 slice computed tomography (CT) scanner to investigate the extent of contrast distribution. A chest compression simulator was then designed and built to allow static CT imaging of 1cm incremental cadaver chest compressions to a depth of 5cm. RESULTS: Mechanical compressions: Ten cases were recruited for the CT angiography component of the study. Two were subsequently excluded from the study at the time of the initial, non-contrast PMCT scan. A further case was recruited in Emergency Department (ED). CT demonstrable antegrade arterial contrast distribution was achieved in 2 cases. The other 7 cases, including that undertaken in ED shortly after death, showed venous retrograde flow. Incremental compressions: Five new cases underwent incremental chest compression imaging. All cases demonstrated compression of the sternum, ribs, atria and great vessels. The right and left ventricles were not compressed, but moved laterally and inferiorly, further into the left chest cavity. The left hemi-diaphragm, stomach and liver moved inferiorly. The sternum, ventricles, hemi-diaphragm, stomach and liver all moved back to their original position on incremental release. CONCLUSION: The study suggests that with further protocol modification and access to human cadavers as near to death as possible, chest compression post mortem computed angiography (CCPMCTA) could be used as a model for the study of human vascular flow and heart movement during CPR.

Diagnostic accuracy of post-mortem CT with targeted coronary angiography versus autopsy for coroner-requested post-mortem investigations: a prospective, masked, comparison study.

BACKGROUND: England and Wales have one of the highest frequencies of autopsy in the world. Implementation of post-mortem CT (PMCT), enhanced with targeted coronary angiography (PMCTA), in adults to avoid invasive autopsy would have cultural, religious, and potential economic benefits. We aimed to assess the diagnostic accuracy of PMCTA as a first-line technique in post-mortem investigations. METHODS: In this single-centre (Leicester, UK), prospective, controlled study, we selected cases of natural and non-suspicious unnatural death referred to Her Majesty's (HM) Coroners. We excluded cases younger than 18 years, known to have had a transmittable disease, or who weighed more than 125 kg. Each case was assessed by PMCTA, followed by autopsy. Pathologists were masked to the PMCTA findings, unless a potential risk was shown. The primary endpoint was the accuracy of the cause of death diagnosis from PMCTA against a gold standard of autopsy findings, modified by PMCTA findings only if additional substantially incontrovertible findings were identified. FINDINGS: Between Jan 20, 2010, and Sept 13, 2012, we selected 241 cases, for which PMCTA was successful in 204 (85%). Seven cases were excluded from the analysis because of procedural unmasking or no autopsy data, as were 24 cases with a clear diagnosis of traumatic death before investigation; 210 cases were included. In 40 (19%) cases, predictable toxicology or histology testing accessible by PMCT informed the result. PMCTA provided a cause of death in 193 (92%) cases. A major discrepancy with the gold standard was noted in 12 (6%) cases identified by PMCTA, and in nine (5%) cases identified by autopsy (because of specific findings on PMCTA). The frequency of autopsy and PMCTA discrepancies were not significantly different (p=0·65 for major discrepancies and p=0·21 for minor discrepancies). Cause of death given by PMCTA did not overlook clinically significant trauma, occupational lung disease, or reportable disease, and did not significantly affect the overall population data for cause of death (p≥0·31). PMCTA was better at identifying trauma and haemorrhage (p=0·008), whereas autopsy was better at identifying pulmonary thromboembolism (p=0·004). INTERPRETATION: For most sudden natural adult deaths investigated by HM Coroners, PMCTA could be used to avoid invasive autopsy. The gold standard of post-mortem investigations should include both PMCT and invasive autopsy. FUNDING: National Institute for Health Research.

Post-mortem imaging of the infant and perinatal dura mater and superior sagittal sinus using optical coherence tomography.

Infants and young children are likely to present with subdural haemorrhage (SDH) if they are the victims of abusive head trauma. In these cases, the most accepted theory for the source of bleeding is the bridging veins traversing from the surface of the brain to the dura mater. However, some have suggested that SDH may result from leakage of blood from a dural vascular plexus. As post-mortem examination of the bridging veins and dura is challenging, and imaging modalities such as magnetic resonance and computed tomography do not have the resolution capabilities to image small blood vessels, we have trialled the use of intravascular and benchtop optical coherence tomography (OCT) systems for imaging from within the superior sagittal sinus (SSS) and through the dura during five infant/perinatal autopsies. Numerous vessel-like structures were identified using both OCT systems. Measurements taken with the intravascular rotational system indicate that the approximate median diameters of blood vessels entering anterior and posterior segments of the SSS were 110 µm (range 70 to 670 µm, n = 21) and 125 µm (range 70 to 740 µm, n = 23), respectively. For blood vessels close to the wall of the SSS, the median diameters for anterior and posterior segments of the SSS were 80 µm (range 40 to 170 µm, n = 25) and 90 µm (range 30 to 150 µm), respectively. Detailed characterisation of the dural vasculature is important to aid understanding of the source of SDH. High resolution 3-dimensional reconstructions of the infant dural vasculature may be possible with further development of OCT systems.

Post-mortem computed tomography coaxial cutting needle biopsy to facilitate the detection of bacterioplankton using PCR probes as a diagnostic indicator for drowning.

We report for the first time the use of coaxial cutting needle biopsy, guided by post-mortem computed tomography (PMCT), to sample internal body tissues for bacterioplankton PCR analysis to investigate drowning. This technical report describes the biopsy technique, the comparison of the needle biopsy and the invasive autopsy sampling results, as well as the PMCT and autopsy findings. By using this new biopsy sampling approach for bacterioplankton PCR, we have developed on previous papers describing the minimally invasive PMCT approach for the diagnosis of drowning. When such a system is used, the operator must take all precautions to avoid contamination of the core biopsy samples due to the sensitivity of PCR-based analytic systems.

Estimation of postmortem interval using vitreous potassium levels in cases of fatal road traffic collision

AIM OF THE STUDY: To produce a formula that can accurately predict postmortem interval (PMI) based on vitreous potassium levels using road traffic collision fatalities. MATERIAL AND METHODS: Vitreous humour samples were taken from 78 individuals who had died following road traffic collisions between 2010 and 2015. Samples were obtained from both eyes and were sent for on-site analysis. Measurement of potassium was by an indirect ion-specific electrode Siemens diagnostics ADVIA 2400 chemistry system. Exact time of death was known from police reports, the time of postmortem was recorded and the postmortem interval was calculated. Linear regression was then used to analyse the relationship between the two. The impact of age was also assessed. RESULTS: PMI was between 6 and 162 hours. As vitreous potassium increases, the PMI also increases; exhibiting a linear relationship. This is illustrated by a regression equation of PMI = 6.42[K+] - 40.94, R = 0.67 (p < 0.001). This produced a formula closely comparable with three other studies proposed in previous literature and produces estimates that may exceed one calendar day. When both age and medical intervention are accounted for there is an insignificant improvement in prediction. CONCLUSIONS: Validated methods have been used to produce a formula for prediction of PMI using vitreous potassium. Although this is specific to road traffic collisions, the methods are transferable and can be seen to be comparable with other recently published methods. Nonetheless, if greater levels of accuracy are required it is suggested that biomarkers delivering a higher level of precision should still be sought.

Optical clearing of the dura mater using glycerol: a reversible process to aid the post-mortem investigation of infant head injury.

PURPOSE: In cases of suspected abusive head trauma, a thorough and systematic study of the cranium and its contents is essential, preferably using the best available methods for observing the brain and its coverings. Building upon recent developments in skull bone removal techniques in infant autopsies, we have assessed the use of two optical clearing agents (OCAs), glycerol and mannitol, on pediatric dura mater in an attempt to increase the transparency of this tissue and thereby enhance the post-mortem assessment of infant head injuries, particularly subdural hematomas. METHODS: Extracorporeal testing revealed glycerol to be the more effective OCA. Therefore, in situ investigations were commenced using glycerol during 33 pediatric post-mortem examinations. RESULTS: An increase in the transparency of the dura was observed in 32 of the 33 cases, within 1 min of application of the OCA. In a 2 year old with cerebral palsy, only partial optical clearance of the dura was seen, most likely due to a significantly atrophic brain, prominent gelatinous leptomeninges, and abnormally thickened dura. This technique allowed for detection of minimal amounts of subdural bleeding over the convexities, before dissection of the dura, avoiding post-mortem blood spillage from artifactually disrupted bridging veins. Optical clearing of the dura aided in the evaluation of patterns of subdural hemorrhage in three cases of non-accidental head injury, three cases of peri-natal head injury and one case of overlaying, apparently resulting in minor crush injury to the head. CONCLUSIONS: We have demonstrated that glycerol is an effective and easy-to-use OCA to effect the readily reversible optical clearing of human infant calvarial dura at autopsy.

Detection of bacterioplankton using PCR probes as a diagnostic indicator for drowning; the Leicester experience.

Bodies found immersed in water can pose difficulties to the investigating authorities. Pathologists may be assisted with the diagnosis by the use of tests such as the analysis for diatoms or the levels of strontium in the blood, although there is a recognised level of uncertainty associated with these tests. Recent work from Japan has shown that using molecular approaches, most recently real-time polymerase chain reaction (PCR) assays with TaqMan probes for bacterioplankton, it is possible to undertake rapid, less laborious, high throughput tests to differentiate freshwater from marine bacterioplankton and in doing so provide a molecular diagnostic test to assist in the diagnosis of drowning. We report the experiences of a United Kingdom forensic pathology unit in the use of this PCR based system for the diagnosis of drowning. We applied this technique to 20 adult and child cadavers from 4 bath, 12 freshwater, 2 brackish and 2 salt water scenes both from within the United Kingdom and abroad. Drowning was concluded to be the cause of death in 16 of these 20 cases and the PCR method supported this conclusion in 12 of these 16 cases. The PCR did not provide evidence of drowning in the four cases where death was from other causes. We illustrate that this PCR method provides a rapid diagnostic supportive test for the diagnosis of drowning that can be applied to United Kingdom autopsy practice.