State of the art in post-mortem forensic imaging in China

A Virtual, 3D Multimodal Approach to Victim and Crime Scene Reconstruction

In the last two decades, forensic pathology and crime scene investigations have seen a rapid increase in examination tools due to the implementation of several imaging techniques, e.g., CT and MR scanning, surface scanning and photogrammetry. These tools encompass relatively simple visualization tools to powerful instruments for performing virtual 3D crime scene reconstructions. A multi-modality and multiscale approach to a crime scene, where 3D models of victims and the crime scene are combined, offers several advantages. A permanent documentation of all evidence in a single 3D environment can be used during the investigation phases (e.g., for testing hypotheses) or during the court procedures (e.g., to visualize the scene and the victim in a more intuitive manner). Advanced computational approaches to understand what might have happened during a crime can also be applied by, e.g., performing a virtual animation of the victim in the actual context, which can provide important information about possible dynamics during the event. Here, we present an overview of the different techniques and modalities used in forensic pathology in conjunction with crime scene investigations. Based on our experiences, the advantages and challenges of an image-based multi-modality approach will be discussed, including how their use may introduce new visualization modalities in court, e.g., virtual reality (VR) and 3D printing. Finally, considerations about future directions in research will be mentioned.

Application of postmortem computed tomography angiography to settle a medical dispute after aortic dissection surgery: a forensic case report

BACKGROUND

In the present case, we applied postmortem computed tomography angiography (PMCTA) in a medical dispute involving sudden death after cardiovascular surgery.

CASE PRESENTATION

A 39-year-old man underwent aortic arch replacement combined with stented elephant trunk implantation surgery under extracorporeal circulation. All vital signs were stable and he was arranged for discharge seven days after surgery. Several days later, the patient was sent back to the hospital for chest pain and poor appetite. Unfortunately, his condition worsened and he ultimately died. PMCT scanning detect pericardial effusion. Family members suspected that the surgical sutures were not dense enough, causing the patient's postoperative bleeding and resulting in cardiac tamponade and death. PMCTA was performed before autopsy, which showed pericardial effusion. However, postmortem angiography with simulated blood pressure showed no leakage of contrast agent, which guided the subsequent autopsy and histological examinations.

CONCLUSIONS

While many previous postmortem imaging case reports have shown positive results that provided evidence of medical malpractice, the current case excludes the possibility of physician negligence and reasonably settles the medical dispute from another perspective. In short, the PMCTA approach we describe here was an effective tool that can be applied to certain medical-related forensic cases.

Forensic imaging: a powerful tool in modern forensic investigation

Forensic imaging is a non-invasive examination process during the forensic investigation. It is mainly used in forensic pathology as an adjunct to the traditional autopsy. In the past two decades, forensic imaging has been vigorously developed by forensic experts from computed tomography (CT) to multiple augmented techniques through CT and magnetic resonance imaging (MRI). The application field of forensic imaging has also been broadened as its advantages are recognised by more forensic practitioners. In addition to the forensic pathology, this technique has been used in other forensic disciplines, including forensic anthropology, forensic odontology, forensic ballistics and wildlife forensics, etc. This article reviews the development of forensic imaging as the practice and research development in different forensic disciplines based on the relevant literature analysis.

Effects of Loading Conditions on the Pelvic Fracture Biomechanism and Discrimination of Forensic Injury Manners of Impact and Run-Over Using the Finite Element Pelvic Model

This study aimed to systematically simulate the responses of pelvic fracture under impact and run-over to clarify the effects of boundary and loading conditions on the pelvic fracture mechanism and provide complementary quantitative evidence for forensic practice. Based on the THUMS finite element model, we have validated the simulation performance of the model by a real postmortem human pelvis side impact experiment. A total of 54 simulations with two injury manners (impact and run-over), seven loading directions (0°, 30°, 60°, 90°, 270°, 300°, 330°), and six loading velocities (10, 20, 30, 40, 50, and 60 km/h) were conducted. Criteria of effective strain, Von-Mises stress, contact force, and self-designed normalized eccentricity were used to evaluate the biomechanism of pelvic fracture. Based on our simulation results, it’s challenging to distinguish impact from run-over only rely on certain characteristic fractures. Loads on the front and back were less likely to cause pelvic fractures. In the 30°, 60°, 300° load directions, the overall deformation caused a “diagonal” pelvic fracture. The higher is the velocity (kinetic energy), the more severe is the pelvic fracture. The contact force will predict the risk of fracture. In addition, our self-designed eccentricity will distinguish the injury manner of impact and run-over under the 90° loads. The “biomechanical fingerprints” based on logistic regression of all biomechanical variables have an AUC of 0.941 in discriminating the injury manners. Our study may provide simulation evidence and new methods for the forensic community to improve the forensic identification ability of injury manners.

Rupture of the Ascending Aorta Surgical Area Detected Using Isolated Cardiopulmonary Organ Computed Tomography Angiography: An Autopsy Case Report After Cardiac Surgery

ABSTRACT

We report cause of death after cardiac surgery using isolated cardiopulmonary organ computed tomography angiography (CTA) and a conventional autopsy. A 56-year-old man underwent aortic valve replacement and coronary artery bypass graft surgery under extracorporeal circulation. Massive bleeding occurred suddenly, and the patient died 25 days later. An autopsy revealed fibrinous exudate in the mediastinum and tight attachment of the pericardium to the heart; there were also clots and inflammatory exudate in the chest cavity. Separating the organs in the chest cavity was difficult, especially in the surgical area. We extracted the heart and lungs together and performed cardiovascular CTA and image reconstruction. Results showed spillage of the contrast agent from the anterior wall of the ascending aorta, approximately 4.5 cm from the replaced aortic valve. A histological examination confirmed that the site of contrast agent spillage was the sutured area of the ascending aorta, which was infected, necrotic, and had ruptured. Using the CTA approach for isolated cardiopulmonary organ imaging can accurately display the location of an aortic rupture, which further guides organ inspection and tissue sampling, and avoids irreversible damage to key regions. In conclusion, the approach we describe can provide evidence for determining cause of death.

Massive Brainstem and Cerebellum Infarction Due to Traumatic Extracranial Vertebral Artery Dissection in a Motor Traffic Accident: An Autopsy Case Report

ABSTRACT

Traumatic unilateral vertebral artery (VA) injury can cause focal thrombosis and may block the basilar artery which can further lead to ischemic stroke and massive cerebral infarction and subarachnoid hemorrhage and even rapid death. Here, we present an autopsy case with a traumatic extracranial VA dissection in a motor traffic accident, and the identification of cause of death underwent 2 autopsies. A 62-year-old male pedestrian collided with the right rearview mirror of a car and fell down to the ground. He complained pains in the head and neck. Head computed tomography (CT) showed a right linear temporal bone fracture and a small left temporal subdural hematoma. Neck CT and magnetic resonance imaging (MRI) examination showed left transverse process fracture of the sixth cervical vertebra (C6) and left extracranial VA injury. After 6 days of hospitalization, the left temporal subdural hematoma had been nearly absorbed, and the man was discharged home. On day 15 after the traffic accident, the man suffered sudden unconsciousness accompanied by frequent vomiting at home. The man was taken to hospital, and there were no obvious abnormal findings by head CT examination. However, the man soon fell into a coma state and died 2 days later. The first autopsy was performed 7 days after death and confirmed a left transverse process fracture of C6 and that the deceased died of cerebral infarction and secondary subarachnoid hemorrhage caused by blunt force in the motor traffic accident. In the civil lawsuit, the traffic accident wrecker put forward the objection whether the deceased had fatal diseases. The second autopsy (84 days after the death) findings verified the left extracranial VA injury. Histopathological examination further showed intimal dissection and thrombus formation of the left extracranial VA and secondary basal arterial thromboembolism. Massive infarction of the brainstem and cerebellum was disclosed. Therefore, the deceased died of delayed massive brainstem and cerebellum infarction because of left extracranial VA dissection in the motor traffic accident.

Diagnosis of drowning using postmortem computed tomography combined with endoscopic autopsy: A case report

RATIONALE

Postmortem forensic imaging technologies provide a noninvasive/minimally invasive approach for imaging of internal organ structures of the human body to detect injuries, diseases, and other morphologic changes. Currently, postmortem forensic imaging methods have been widely used in determination of the cause of death. However, these methods do not allow histologic examinations. Endoscopic autopsy emerged in the 1990s. Thoracoscopy and laparoscopy are mainly used to examine organs and tissues in the thoracic and abdominal cavity. Target tissues are also sampled for histologic examination. By combining postmortem forensic imaging with endoscopic autopsy, comprehensive examination of the corpse, organs, and sampling for histologic examination can be carried out.

PATIENT CONCERNS

A 34-year-old woman was witnessed jumping into the river, sinking after struggling in the water. The body was found 24 hours later and confirmed with no vital signs. No preexisting medical conditions were known.

DIAGNOSIS, INTERVENTIONS, AND OUTCOMES

Postmortem computed tomography, target coronary postmortem computed tomography angiography, and endoscopic autopsy were performed before conventional autopsy. Laparoscopic examination was used to examine the abdominal organs. The diaphragm and pericardium were cut open from the abdominal cavity to allow access to the examination of lungs and heart. Tissue samples were collected from various organs for histologic examination, and a diatom test was carried out on lung samples. Postmortem computed tomography revealed fluid in the paranasal sinuses, airways, stomach, and duodenum; emphysema aquosum; and mosaic pattern of the lung parenchyma. Endoscopic examination additionally detected Paltauf spots. The results were consistent with those of conventional autopsy. Histologic examination revealed pulmonary congestion, pulmonary edema, pulmonary emphysema, pulmonary hemorrhage, and congestion in multiple organs such as the liver, spleen, and kidneys. Diatoms were detected in lung tissues, which were identical in morphology to diatoms in water samples collected from the scene. The cause of death was determined as drowning.

CONCLUSION

Combining forensic imaging and endoscopic autopsy for postmortem examination yields a more comprehensive and scientific finding, and the combination is minimally invasive and more acceptable to the family members. This method can be used as an alternative for conventional autopsy under specific circumstances.

Latest developments in post-mortem foetal imaging

A sustained decline in parental consent rates for perinatal autopsies has driven the development of less-invasive methods for death investigation. A wide variety of imaging modalities have been developed for this purpose and include post-mortem whole body magnetic resonance imaging (MRI), ultrasound, computed tomography (CT) and micro-focus CT techniques. These are also vital for "minimally invasive" methods, which include potential for tissue sampling, such as image guidance for targeted biopsies and laparoscopic-assisted techniques. In this article, we address the range of imaging techniques currently in clinical practice and those under development. Significant advances in high-field MRI and micro-focus CT imaging show particular promise for smaller and earlier gestation foetuses. We also review how MRI biomarkers such as diffusion-weighted imaging and organ volumetric analysis may aid diagnosis and image interpretation in the absence of autopsy data. Three-dimensional printing and augmented reality may help make imaging findings more accessible to parents, colleagues and trainees.

Virtual reality and integrated crime scene scanning for immersive and heterogeneous crime scene reconstruction

Crime scene reconstruction plays a significant role in crime solving by helping to determine the course of events. Non-invasive, high-resolution measurement and increased insight are always the goal of forensic crime scene documentation. However, entire crime scenes cannot be effectively reconstructed with traditional methods. In this study, we present a portable system that consists of a laser scanner, two hand-held structured light scanners and a low-cost virtual reality (VR) headset with a mobile power supply to conduct multi-angle and omnidirectional three-dimensional spatial data collection of crime scenes. To demonstrate practical use, a real case has been analysed to verify the feasibility and effectiveness of the system. The system accurately obtains information on decedent injuries, possible injury-inflicting tools and on-site traces. Various types of evidence from the crime scene can be jointly studied by three-dimensional visualization to develop a cohesive story. The data are presented via immersive VR rather than displayed on computer screens. The relationship between evidence chains enables us to achieve a complete crime scene reconstruction, using the specialized knowledge of experts and computer-aided forensic tools to analyse the causes of damage and identify suspects. The use of three- dimensional imaging techniques allows a more insightful survey and several useful analyses, such as accurate measurement, relative blood source location determination and injury-inflicting tool comparison.

Prediction of injury risks and features among scooter riders through MADYMO reconstruction of a scooter-microvan accident: Identifying the driver and passengers

In dealing with a scooter-related traffic accident with rider death, it is necessary to identify the driver responsible for the accident. This study aimed to reconstruct the kinematics of a scooter-microvan accident involving three riders and explored the differences in injury risks and characteristics of the scooter driver and passengers. We reconstructed a real accident by using MADYMO multi-body simulation software. Moreover, we designed two-variable simulation experiments to analyze how the velocity and impact angle of the microvan are related to the injuries of the three riders. When the microvan speed is set at 18 km/h and that of the scooter is set at 28.8 km/h, the simulated kinematics correlates well with real accident data, and the impact positions and injury parameters correlate well with the actual injuries. When the impact angle is smaller than 30° and the microvan impact velocity is lower than 40 km/h, the head injury of the driver is more life-threatening than the corresponding injuries of the rear passengers. When the impact angle is 15° and the microvan impact velocity is in the range of 0-20 km/h, the femur fracture risk is higher for the driver than for passengers. As the impact angle increases to 45°, passengers have a higher risk of femur fracture than the driver in the velocity range of 0-10 km/h. This impact velocity range becomes 0-30 km/h at an impact angle of 60° and then 40-70 km/h at an impact angle of 90°. Our study shows that the multibody method can reconstruct accidents and predict the different injury features and risks between the driver and passengers, which is useful in identifying the driver.

Autopsy diagnosis of acupuncture-induced bilateral tension pneumothorax using whole-body postmortem computed tomography: A case report

RATIONALE

Acupuncture, a component of traditional Chinese medicine, is also a well-known form of complementary and alternative medicine. Serious adverse events of acupuncture have been reported, including the acupuncture-related pneumothorax which is a rare but fatal condition sometimes. The pneumothorax was related to needle insertion in the upper back or paraspinal area and the reported victims suffered from either unilateral or bilateral pneumothorax. Postmortem computed tomography has advantages in the detection of pathologic gas and is being considered as a useful visualization tool for diagnosing the cause of death.

PATIENT CONCERNS

A 52-year-old man underwent acupuncture and cupping treatment at an illegal Chinese medicine clinic for neck and back discomfort and was admitted to the hospital with severe gasp and dyspnea about 30 hours later. The patient suddenly became unconscious with heart rate and blood pressure lost and died after cardiopulmonary resuscitation. Diagnosis, interventions and outcomes: Whole-body postmortem computed tomography of the victim revealed collapse of the both lungs and mediastinal compression, which was also confirmed by autopsy. More than 20 pinprick injuries were found on the skin of the upper and lower back in which multiple pinpricks were located on the body surface projection of the lungs. The cause of death was concluded as acute respiratory and circulatory failure due to acupuncture-induced bilateral tension pneumothorax.

LESSONS

Acupuncture-induced tension pneumothorax is rare and should be recognized by forensic pathologists. Postmortem computed tomography can be used to detect and accurately evaluate the severity of pneumothorax before autopsy and can play a supporting role in determining the cause of death.

Identification of pre-impact conditions of a cyclist involved in a vehicle-bicycle accident using an optimized MADYMO reconstruction combined with motion capture

The aim of the present study was to develop an improved method, using MADYMO multi-body simulation software combined with an optimization method and three-dimensional (3D) motion capture, for identifying the pre-impact conditions of a cyclist (walking or cycling) involved in a vehicle-bicycle accident. First, a 3D motion capture system was used to analyze coupled motions of a volunteer while walking and cycling. The motion capture results were used to define the posture of the human model during walking and cycling simulations. Then, cyclist, bicycle and vehicle models were developed. Pre-impact parameters of the models were treated as unknown design variables. Finally, a multi-objective genetic algorithm, the nondominated sorting genetic algorithm II, was used to find optimal solutions. The objective functions of the walk parameter were significantly lower than cycle parameter; thus, the cyclist was more likely to have been walking with the bicycle than riding the bicycle. In the most closely matched result found, all observed contact points matched and the injury parameters correlated well with the real injuries sustained by the cyclist. Based on the real accident reconstruction, the present study indicates that MADYMO multi-body simulation software, combined with an optimization method and 3D motion capture, can be used to identify the pre-impact conditions of a cyclist involved in a vehicle-bicycle accident.