Computed tomography of projectile injuries

Korean radiographers' awareness, experiences, and education needs in forensic medicine and forensic radiology

This study assesses the need for education in forensic medicine and forensic radiology among radiographers by investigating the perceptions and experiences of Korean radiographers working in medical institutions. A structured questionnaire was administered to participants, collected, and analyzed. The results showed that despite receiving frequent forensic cases, Korean radiographers face difficulties in taking appropriate measures about forensic radiology due to a lack of awareness and knowledge of its forensic aspects. The participants indicated that university education in forensic medicine and forensic radiology is necessary. Therefore, it is imperative to develop and implement policies for forensic education programs to enhance radiographers' forensic knowledge and capabilities. Universities should conduct courses on forensic radiology and provide continuing education for radiographers working in this field.

Post-mortem CT in the investigation of homicides

AIM

To investigate the reliability of post-mortem computed tomography (PMCT) in a case series of homicides involving blunt-force, sharp-force, and ballistic trauma.

MATERIALS AND METHODS

The study investigates 16 homicide cases that underwent PMCT before autopsy. Two radiologists assessed the PMCT examinations and the data were compared to the forensic pathology findings. Data were organised in broad categories: foreign bodies, external injuries, soft-tissue and organ injuries, fractures, air in cavities, fluid collections, random pathology, and wound track. Findings were organised by systems: head and neck, thorax, abdomen and pelvis, extremities. Cohen's kappa statistics were used to assess observer agreement.

RESULTS

Six gunshot-related homicides (37.5%), seven sharp-force-related homicides (43.75%), two blunt-force-related deaths (12.5%), and one homicide due to mechanical asphyxia (1.25%) were analysed. A total of 64 fractures were reported by the pathologists, 67 by radiologist 1 and 68 by radiologist 2. Agreement was deemed substantial in all cases. Pathologists failed to report gas in cavities while radiologists underreported superficial injuries.

CONCLUSION

An overall observation was that less accurate findings were produced by the blinded radiologist in comparison to the non-blinded one. The extremeness of homicides obscured the interpretation of PMCT leading to the observed discrepancies. The combination of PMCT and autopsies is deemed optimal when investigating homicidal events.

Gunshot Wounds: Ballistics, Pathology, and Treatment Recommendations, with a Focus on Retained Bullets

As the epidemic of gunshot injuries and firearm fatalities continues to proliferate in the United States, knowledge regarding gunshot wound (GSW) injury and management is increasingly relevant to health-care providers. Unfortunately, existing guidelines are largely outdated, written in a time that high-velocity weapons and deforming bullets were chiefly restricted to military use. Advances in firearm technology and increased accessibility of military grade firearms to civilians has exacerbated the nature of domestic GSW injury and complicated clinical decision-making, as these weapons are associated with increased tissue damage and often result in retained bullets. Currently, there is a lack of literature addressing recent advances in the field of projectile-related trauma, specifically injuries with retained bullets. This review aims to aggregate the available yet dispersed findings regarding ballistics, GSW etiology, and treatment, particularly for cases involving retained projectiles.

Characterisation of retained energised fragments from explosive devices in military personnel

INTRODUCTION

Characterising the shapes, dimensions and overall numbers of fragments produced by explosive devices is important for determining methods of potential mitigation, such as personal armour. The aim of this investigation was to compare the mass of excised fragments with that predicted from CT to ascertain the validity of using such an approach to measure retained fragments for multiple body areas using CT alone.

METHOD

27 retained fragments excised from consecutive patients treated at a US Role 3 Medical Treatment Facility in Afghanistan were examined. Each fragment was measured in three dimensions and the mass was obtained to estimate the density and thereby probable composition. These same excised fragments were identified radiologically and their predicted masses calculated and compared with the known masses with a paired t-test. The total numbers of retained fragments in each of four body areas for 20 casualties were determined radiographically and the mass of the largest fragment in each body region estimated.

RESULTS

Excised fragments were most commonly metallic (17/27, 63%), with masses ranging from 0.008 to 37.6 g. Mean mass predicted from CT was significantly different from than that measured (p=0.133), with CT underestimating true mass by 5%-17%. 889/958 (93%) retained fragments appeared metallic on imaging, with the most commonly affected body areas being the torso and upper extremity (45% of casualties).

CONCLUSIONS

Predicting the mass of metallic fragments from CT was possible with an error margin of up to 5%, but was less accurate for non-metallic fragments such as stone. Only 3% of fragments were removed through debridement or purposeful excision; these were not just the largest or most superficial. This suggests that future retrospective analysis of the dimensions and predicted masses of retained fragments in larger casualty cohorts of service personnel is potentially feasible within a small margin of error.

Virtopsy and Living Individuals Evaluation Using Computed Tomography in Forensic Diagnostic Imaging

The applications of forensic radiology involve both Virtopsy both studies on living people - to demonstrate bone age, search for foreign bodies, such as voluntary injection of drug ovules or surgical sponges accidentally forgotten, to assess gunshot wounds, to evaluate injuries by road accidents, and cases of violence or abuse (both in adults and in children). Computed tomography is the most used imaging tool used in forensic pathology and its indications are mainly focused on cases of unnatural deaths or when a crime is suspected. It is preferred over the standard autopsy in selected cases, such as in putrefied, carbonized or badly damaged bodies; or as a preliminary evaluation in mass disasters.

Synergistic Role of Newer Techniques for Forensic and Postmortem CT Examinations

OBJECTIVE

The aim of this article is to provide an overview of newer techniques and postprocessing tools that improve the potential impact of CT in forensic situations.

CONCLUSION

CT has become a standard tool in medicolegal practice. Postmortem CT is an essential aid to the pathologist during autopsies. Advances in technology and software are constantly leading to advances in its performance.

Post-autopsy computed tomography. Pros and cons in a firearm death

Many studies have focused on the importance of post-mortem computed tomography (PMCT) prior to or in substitution of standard forensic autopsies in case of firearm death. However, due to the fact that PMCT is not routinely performed in all countries, in cases of death abroad it can happen that a CT scan is performed only after a first autopsy. A case of post-mortem re-examination, including the external examination and a post-autopsy computed tomography (PACT), of a gunshot victim of homicide in a foreign country is presented, and the pros and cons of imaging in post-autopsy setting are discussed. PACT could be a tool for carrying out more complete investigations and for obtaining information on bone injuries and foreign bodies trapped within peripheral soft tissues that can be re-analyzed after the arrival of the first autopsy report. Given that the value of information derived may be strongly influenced by the previously performed autopsy, in order to process the definitive considerations it is necessary to compare and interpret the data obtained through PACT with the results of the first autopsy, and to continue the international cooperation effort and the application of international guidelines in order to share information at the repatriation of the corpse.

A systematic review on ricochet gunshot injuries

Ricocheted bullets may still retain sufficient kinetic energy to cause gunshot injuries. Accordingly, this paper reviews the literature surrounding gunshot injuries caused by ricocheted bullets. In doing so, it discusses the characteristics of ricochet entrance wounds and wound tracks, noting several important considerations for assessment of a possible ricochet incident. The shapes of ricochet entrance wounds vary, ranging from round holes to elliptical, large and irregular shapes. Pseudo-stippling or pseudo-gunpowder tattooing, pseudo-soot blackening and tumbling abrasions seen on the skin surrounding the bullet hole are particularly associated with ricochet incidents. Ricocheted bullets have a reduced capability for tissue penetration. Most of the resulting wound tracks are short, of large diameter and irregular-all artefacts of the instability of a bullet that has ricocheted. A ricocheted hollow-point bullet, in particular, may overpenetrate the tissue when the bullet nose is deformed or fails to enter the body in a nose-forward orientation. Similarly, internal ricochet may occur when a bullet strikes hard tissue. Postmortem computed tomographic imaging is useful for localising a bullet and its fragments in the body and characterising the wound track. Ricochet cannot be ruled out in normal-appearing entrance wounds unless that finding is supported by other evidence, including the geometrical constraints of the shooting scene and the absence of ricochet marks and a ricocheted bullet.

Forensic postmortem computed tomography: volumetric measurement of the heart and liver

PURPOSE

The purpose of this study was to investigate the utility of postmortem computed tomography (PMCT) images in estimating organ sizes and to examine the use of the cardiothoracic ratio (CTR).

METHODS

We included 45 individuals (19 females), who underwent a medico-legal autopsy. Using the computer software program Mimics^®, we determined in situ heart and liver volumes derived from linear measurements (width, height and depth) on a whole body PMCT-scan, and compared the volumes with ex vivo volumes derived by CT-scan of the eviscerated heart and liver. The ex vivo volumes were also compared with the organ weights. Further, we compared the CTR with the ex vivo heart volume and a heart weight-ratio (HWR). Intra- and inter-observer analyses were performed.

RESULTS

We found no correlation between the in situ and ex vivo volumes of the heart and liver. However, a highly significant correlation was found between the ex vivo volumes and weights of the heart and liver. No correlations between CTR and the ex vivo heart volume nor with HWR was found. Concerning cardiomegaly, we found no agreement between the CTR and HWR. The intra- and inter-observer analyses showed no significant differences.

CONCLUSIONS

Noninvasive in situ PMCT methods for organ measuring, as performed in this study, are not useful tools in forensic pathology. The best method to estimate organ volume is a CT-scan of the eviscerated organ. PMCT-determined CTR seems to be useless for ascertaining cardiomegaly, as it neither correlated with the ex vivo heart volume nor with the HWR.

Imaging for homicide investigations

The authors present the opportunities of the application of post-mortem imaging, focusing on post-mortem computed tomography and post-mortem computed tomography angiography in modern forensic investigation of homicide cases. The paper is based on scientific publications related to the subject from ca. the past 10 years, supplemented by the authors' own experiences. The article is illustrated with reconstructions based on the authors' own cases related to homicide due to ballistic/sharp/blunt trauma. As is shown, the results of evaluation of post-mortem computed tomography allow better diagnosis, documentation and visualisation of forensic examinations.

The role of early postmortem CT in the evaluation of support-line misplacement in patients with severe trauma

OBJECTIVE

The purpose of this study was to retrospectively assess the role of early postmortem CT in evaluating support-line misplacement to improve future treatment in the trauma setting.

MATERIALS AND METHODS

We included all postmortem CT examinations that were performed for trauma patients within the 1st hour after declaration of death in our tertiary medical center between August 1, 2008, and August 31, 2013. Correct placement of the following support lines was evaluated: endotracheal tubes (ETTs), chest drains, central venous catheters (CVCs), and nasogastric tubes (NGTs). Prehospital resuscitation efforts were started in all cases.

RESULTS

Early postmortem CT was performed on average 22 minutes after declaration of death in 25 consecutive patients with severe trauma. Overall, 14 subjects (56%) had suboptimal or misplaced support lines. Of ETTs inserted into 18 trauma victims; three (17%) were mislaid in the right main bronchus and five (28%) were near or at the level of the carina. Of chest drains inserted into 13 subjects, 10 were suboptimally positioned (77%). Of CVCs inserted into eight subjects (seven femoral and one brachiocephalic), one femoral CVC (13%) was malpositioned in the soft tissues of the pelvis. Of NGTs inserted in five trauma victims, one was folded within the pharynx.

CONCLUSION

Early postmortem CT for patients who have experienced severe poly-trauma can be of important educational value to radiologists and the trauma teams, providing immediate feedback regarding the location of the support lines and possibly contributing to improved training and command of the learning curve by medical staff.

Adult post-mortem imaging in traumatic and cardiorespiratory death and its relation to clinical radiological imaging

The use of post-mortem imaging is expanding throughout the world with increasing use of advanced imaging techniques, such as contrast-enhanced CT and MRI. The questions asked of post-mortem imaging are complex and can be very different, for example for natural sudden death investigation will focus on the cause, whereas for trauma the cause of death is often clear, but injury patterns may be very revealing in investigating the background to the incident. Post-mortem imaging is different to clinical imaging regarding both the appearance of pathology and the information required, but there is much to learn from many years of clinical research in the use of these techniques. Furthermore, it is possible that post-mortem imaging research could be used not only for investigating the cause of death but also as a model to conduct clinically relevant research. This article reviews challenges to the development of post-mortem imaging for trauma, identification and cardiorespiratory death, and how they may be influenced by current clinical thinking and practice.

Performance of lead-free versus lead-based hunting ammunition in ballistic soap

Background

Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community.

Methods

We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments.

Results

All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets.

Conclusion

The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion, deflection angle, cavity shape, and reproducibility, showing that similar terminal ballistic behavior can be achieved. Furthermore, the volumetric image processing allowed superior analysis compared to methods that involve cutting of the soap blocks.

Postmortem 3-D reconstruction of skull gunshot injuries

BACKGROUND

In cases of severe decomposition or skeletonization of a corpse after cerebral gun shot injury it is difficult to exactly reconstruct the bullet path in the brain. However, in case of murder or homicide this might become necessary to answer forensic questions such as the ability to move or other actions of the victim.

MATERIALS AND METHODS

Therefore a method in terms of three dimensional reconstruction technique was developed by fusing computed tomography scans (CT) of the original skull and magnetic resonance images (MRI) of a normal brain of adequate size. Hereby five cases were investigated.

RESULTS

In three cases an excellent concordance between the reconstructed bullet trajectory and the autopsy reports was achieved. In one case the original brain was not available for CT-scanning due to previous autopsy. However, the findings were in line with the pathology report. In one case there was a difference of about 1-2 cm between the original autopsy description and the reconstructed bullet path. This was due to only a part of the skull being available for image reconstruction.

CONCLUSION

The findings suggest that this method can successfully be applied to adequately reconstruct bullet paths in cases of completely skeletonized skulls, but should carefully be used in cases of incomplete skulls.

Identifying future 'unexpected' survivors: a retrospective cohort study of fatal injury patterns in victims of improvised explosive devices

OBJECTIVES

To identify potentially fatal injury patterns in explosive blast fatalities in order to focus research and mitigation strategies, to further improve survival rates from blast trauma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

UK military personnel killed by improvised explosive device (IED) blasts in Afghanistan, November 2007-August 2010.

SETTING

UK military deployment, through NATO, in support of the International Security Assistance Force (ISAF) mission in Afghanistan.

DATA SOURCES

UK military postmortem CT records, UK Joint Theatre Trauma Registry and associated incident data.

MAIN OUTCOME MEASURES

Potentially fatal injuries attributable to IEDs.

RESULTS

We identified 121 cases, 42 mounted (in-vehicle) and 79 dismounted (on foot), at a point of wounding. There were 354 potentially fatal injuries in total. Leading causes of death were traumatic brain injury (50%, 62/124 fatal injuries), followed by intracavity haemorrhage (20.2%, 25/124) in the mounted group, and extremity haemorrhage (42.6%, 98/230 fatal injuries), junctional haemorrhage (22.2%, 51/230 fatal injuries) and traumatic brain injury (18.7%, 43/230 fatal injuries) in the dismounted group.

CONCLUSIONS

Head trauma severity in both mounted and dismounted IED fatalities indicated prevention and mitigation as the most effective strategies to decrease resultant mortality. Two-thirds of dismounted fatalities had haemorrhage implicated as a cause of death that may have been anatomically amenable to prehospital intervention. One-fifth of the mounted fatalities had haemorrhagic trauma which currently could only be addressed surgically. Maintaining the drive to improve all haemostatic techniques for blast casualties, from point of wounding to definitive surgical proximal vascular control, alongside the development and application of novel haemostatic interventions could yield a significant survival benefit. Prospective studies in this field are indicated.

Importance of 3D-CT imaging in single-bullet cranioencephalic gunshot wounds

PURPOSE

The aim of this paper is to demonstrate that computed tomography (CT) and three-dimensional (3D) CT imaging techniques can be useful tools for evaluating gunshot wounds of the skull in forensic medicine. Three purposes can be achieved: (1) identifying and recognising the bullet entrance wound - and exit wound, if present; (2) recognising the bullet's intracranial course by studying damage to bone and brain tissue; (3) suggesting hypotheses as to the dynamics of the event.

MATERIALS AND METHODS

Ten cadavers of people who died of a fatal head injury caused by a single gunshot were imaged with total-body CT prior to conventional autoptic examination. Three-dimensional-CT reconstructions were obtained with the volume-rendering technique, and data were analysed by two independent observers and compared with autopsy results.

RESULTS

In our experience, CT analysis and volumetric reconstruction techniques allowed the identification of the bullet entrance and exit wounds and intracranial trajectory, as well as helping to formulate a hypothesis on the extracranial trajectory to corroborate circumstantial evidence.

CONCLUSIONS

CT imaging techniques are excellent tools for addressing the most important questions of forensic medicine in the case of gunshot wounds of the skull, with results as good as (or sometimes better than) traditional autoptic methods.

The survival of metallic residues from gunshot wounds in cremated bone: a radiological study

In literature, many studies have been performed in order to investigate the presence of GSR ("gunshot residue") and metallic residues in general with radiological techniques on several types of material, but the survival of metallic residues on charred samples has never been systematically performed. In this study, 31 adult bovine ribs underwent a shooting test. Every rib was shot with a single bullet, at a near-contact shooting distance, using two kinds of projectile: 17 samples were shot with a full metal-jacketed bullet and the remaining 14 with an unjacketed bullet. After the shooting test, every rib underwent a "charring cycle" in an electric oven up to 800°C. Every sample underwent radiological investigation with conventional radiography, before and after the burning process, to evaluate any changes in number and distribution of metallic residues. Radiographs showed survival of radiopaque residues in every sample, even after the charring process, especially when the bullet used was of the unjacketed type.

Visualisation of the temporary cavity by computed tomography using contrast material

The temporary cavity of a missile produces radial tears in ordnance gelatine, which correlate to the energy transfer. Computed tomography is a useful and non-destructive method to examine gelatine blocks. However, the tears give only few radiocontrast by air filling, which decreases with the time past shooting. Therefore, systematically, a radiocontrast material was searched to enhance the contrast. Different contrast materials were amalgamated to acryl paint, and about 7 g was sealed in a foil bag, which was integrated in the front of a standard 10% gelatine cylinder. Shots with Action-5 expanding bullets were performed from a 5-m distance. Gelatine was scanned by multi-slice computed tomography. The multiplanar reconstructed images were compared to mechanically cut slices of 1 cm thickness. It was shown experimentally that iodine containing water-soluble contrast material did not give sufficient contrast and caused diffusion artefacts. Best results were obtained by barium sulphate emulsion. The amount of acryl paint was sufficient to colour the tears for optical scanning. The radiocontrast of barium leads to satisfying imaging of tears and allowed the creation of a three-dimensional reconstruction of the temporary cavity. Comparison of optical and radiological results showed an excellent correlation, but absolute measures in computed tomographic (CT) images remained lower compared with optically gathered values in the gelatine slices. Combination of paint and contrast material for CT examination will facilitate the evaluation of complex ballistic models and increase accuracy.

Computed tomography (CT) virtual autopsy and classical autopsy discrepancies: radiologist's error or a demonstration of post-mortem multi-detector computed tomography (MDCT) limitation?

Modern imaging technologies, such as computed tomography (CT) techniques, represent a great challenge in forensic pathology. The field of forensics has experienced a rapid increase in the use of these new techniques to support investigations on critical cases, as indicated by the implementation of CT scanning by different forensic institutions worldwide. Advances in CT imaging techniques over the past few decades have finally led some authors to propose that virtual autopsy, a radiological method applied to post-mortem analysis, is a reliable alternative to traditional autopsy, at least in certain cases. The authors investigate the occurrence and the causes of errors and mistakes in diagnostic imaging applied to virtual autopsy. A case of suicide by a gunshot wound was submitted to full-body CT scanning before autopsy. We compared the first examination of sectional images with the autopsy findings and found a preliminary misdiagnosis in detecting a peritoneal lesion by gunshot wound that was due to radiologist's error. Then we discuss a new emerging issue related to the risk of diagnostic failure in virtual autopsy due to radiologist's error that is similar to what occurs in clinical radiology practice.