Research Progress and Forensic Application of Human Vascular Finite Element Modeling and Biomechanics.

The finite element method (FEM) is a mathematical method for obtaining approximate solutions to a wide variety of engineering problems. With the development of computer technology, it is gradually applied to the study of biomechanics of human body. The application of the combination of FEM and biomechanics in exploring the relationship between vascular injury and disease, and pathological mechanisms will be a technological innovation for traditional forensic medicine. This paper reviews the construction and development of human vascular FEM modeling, and its research progress on the vascular biomechanics. This paper also looks to the application prospects of FEM modeling in forensic pathology.

Forensic Pathological Diagnosis of Acute and Old Myocardial Infarction Using Fourier Transform Infrared Spectroscopy.

OBJECTIVES: Fourier transform infrared spectroscopy (FTIR) was used to analyze myocardial infarction tissues at different stages of pathological change to achieve the forensic pathology diagnosis of acute and old myocardial infarction. METHODS: FTIR spectra data of early ischemic myocardium, necrotic myocardium, and myocardial fibrous tissue in the left ventricular anterior wall of the sudden death group of atherosclerotic heart disease and the myocardium of the normal control group were collected using hematoxylin-eosin (HE) and immunohistochemistry (IHC) staining as a reference, and the data were analyzed using multivariate statistical analysis. RESULTS: The mean normalized spectra of control myocardium, early ischemic myocardium and necrotic myocardium were relatively similar, but the mean second derivative spectra were significantly different. The peak intensity of secondary structure of proteins in early ischemic myocardium was significantly higher than in other types of myocardium, and the peak intensity of the α-helix in necrotic myocardium was the lowest. The peaks of amide Ⅰ and amide Ⅱ in the mean normalized spectra of myocardial fibrous tissue significantly shifted towards higher wave numbers, the peak intensities of amide Ⅱ and amide Ⅲ were higher than those of other types of myocardium, and the peak intensities at 1 338, 1 284, 1 238 and 1 204 cm-1 in the mean second derivative spectra were significantly enhanced. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) showed that FTIR could distinguish different types of myocardium. CONCLUSIONS: FTIR technique has the potential to diagnose acute and old myocardial infarction, and provides a new basis for the analysis of the causes of sudden cardiac death.

Evaluating Subtle Pathological Changes in Early Myocardial Ischemia Using Spectral Histopathology.

Early myocardial ischemia (EMI) is morphologically challenging, and the results from conventional histological staining may be subjective, imprecise, or even silent. The size of myocardial necrosis determines the acute and long-term mortality of EMI. The precise diagnosis of myocardial ischemia is critical for both clinical management and forensic investigation. Fourier transform infrared (FTIR) spectroscopic imaging is a highly sensitive tool for detecting protein conformations and imaging protein profiles. The aim of this study was to evaluate the application of FTIR imaging with multivariate analysis to detect biochemical changes in the protein conformation in the early phase of myocardial ischemia and to visually classify different disease states. The spectra and curve fitting results revealed that the total protein content decreased significantly in the EMI group and that the α-helix content of the secondary protein structure continuously decreased as ischemia progressed, while the ß-sheet content increased. Differences in the control and EMI groups and perfused and ischemic myocardium were confirmed using principal component analysis and partial least squares discriminant analysis. Next, two support vector machine classifiers were effectively created. The accuracy, recall, and precision were 99.98, 99.96, and 100.00%, respectively, to differentiate the EMI group from the control group and 99.25, 98.95, and 99.54%, respectively, to differentiate perfused and ischemic myocardium. Ultimately, high EMI diagnostic accuracy was achieved with 100.00% recall and 100.00% precision, and ischemic myocardium diagnostic accuracy was achieved with 99.30% recall and 99.53% precision for the test set. This pilot study demonstrated that FTIR imaging is a powerful automated quantitative analysis tool to detect EMI without morphological changes and will improve diagnostic accuracy and patient prognosis.

Preliminary study on the mechanisms of ankle injuries under falling and impact conditions based on the THUMS model.

Ankle injuries are common in forensic practice, which are mainly caused by falling and traffic accidents. Determining the mechanisms and manners of ankle injuries is a critical and challenging problem for forensic experts. The identification of the injury mechanism is still experience-based and strongly subjective. There also lacks systematic research in current practice. In our study, based on the widely used Total Human Model of Safety 4.0 (THUMS 4.0), we utilized the finite element (FE) method to simulate ankle injuries caused by falls from different heights (5 m, 10 m and 20 m) with different landing postures (natural posture, inversion, eversion, plantar-flexion and dorsi-flexion) and injuries caused by impacts from different directions (anterior-posterior, lateral-medial and posterior-anterior) with different speeds (10 m/s, 15 m/s and 20 m/s) at different sites (ankle and lower, middle and upper sections of leg). We compared the injury morphology and analyzed the mechanisms of ankle injuries. The results showed that falling causes a specific compression fracture of the distal tibia, while fractures of the tibia and fibula diaphysis and ligament injuries caused by falling from a lower height or inversion, planter flexion or dorsiflexion at a large angle are not distinguishable from the similar injury patterns caused by impact on the middle and upper segments of the leg. No obvious compression fracture of the tibia distal was caused by the impacts, whereas ligament injuries and avulsion fractures of the medial or lateral condyle and fractures of the diaphysis of the tibia and fibula were observed. Systematic studies will be helpful in reconstructing the ankle injury processes and analyzing the mechanisms in forensic practice, providing a deeper understanding of ankle injury mechanisms for forensic experts.

Use of deep learning in forensic sex estimation of virtual pelvic models from the Han population.

Accurate sex estimation is crucial to determine the identity of human skeletal remains effectively. Here, we developed convolutional neural network (CNN) models for sex estimation on virtual hemi-pelvic regions, including the ventral pubis (VP), dorsal pubis (DP), greater sciatic notch (GSN), pelvic inlet (PI), ischium, and acetabulum from the Han population and compared these models with two experienced forensic anthropologists using morphological methods. A Computed Tomography (CT) dataset of 862 individuals was divided into the subgroups of training, validation, and testing, respectively. The CT-based virtual hemi-pelvises from the training and validation groups were used to calibrate sex estimation models; and then a testing dataset was used to evaluate the performance of the trained models and two human experts on the sex estimation of specific pelvic regions in terms of overall accuracy, sensitivity, specificity, F1 score, and receiver operating characteristic (ROC) curve. Except for the ischium and acetabulum, the CNN models trained with the VP, DP, GSN, and PI images achieved excellent results with all the prediction metrics over 0.9. All accuracies were superior to those of the two forensic anthropologists in the independent testing. Notably, the heatmap results confirmed that the trained CNN models were focused on traditional sexual anatomic traits for sex classification. This study demonstrates the potential of AI techniques based on the radiological dataset in sex estimation of virtual pelvic models. The excellent sex estimation performance obtained by the CNN models indicates that this method is valuable to proceed with in prospective forensic trials.Key pointsDeep learning can be a promising alternative for sex estimation based on the pelvis in forensic anthropology.The deep learning convolutional neural network models outperformed two forensic anthropologists using classical morphological methods.The heatmaps indicated that the most known sex-related anatomic traits contributed to correct sex determination.

Reconstruction of a real-world car-to-pedestrian collision using geomatics techniques and numerical simulations.

The aim of this study is to provide an improved method for traffic accident reconstruction based on geomatics techniques and numerical simulations. A combination of various techniques was used. First, an unmanned aerial vehicle (UAV), laser scanner and structured-light scanner were used to obtain information on the accident scene, vehicle and victim. The collected traces provided detailed initial impact conditions for subsequent numerical simulations. Then, multi-body system (MBS) simulations were conducted to reconstruct the kinematics of the car-to-pedestrian collision. Finally, a finite element (FE) simulation using the THUMS model was performed to predict injuries. A real-life vehicle-pedestrian collision was used to verify the feasibility and effectiveness of this method. The reconstruction result revealed that the kinematic and injury predictions of the numerical simulations effectively conformed to the surveillance video and investigation of the actual accident. UAV photogrammetry was demonstrated to be more efficient in accident data collection than hand sketch and measurement, and 3D laser scanning enabled an easier and more accurate modeling process of vehicle. The present study shows the feasibility of this method for use in traffic accident reconstruction.

Cerebral hemorrhage caused by shaking adult syndrome? Evidence from biomechanical analysis using 3D motion capture and finite element models.

The present study combined three-dimensional (3D) motion capture with finite element simulation to reconstruct a real shaking adult syndrome (SAS) case and further explore the injury biomechanics of SAS. The frequency at which an adult male can shake the head of another person, head-shaking amplitude, and displacement curves was captured by the VICON 3D motion capture system. The captured shaking frequency and shaking curve were loaded on the total human model for safety (THUMS) head to simulate the biomechanical response of brain injury when a head was shaken in anterior-posterior, left-right, and left anterior-right posterior directions at frequencies of 4 Hz (Hz), 5 Hz, 6 Hz, and 7 Hz. The biomechanical response of the head on impact in the anterior, posterior, left, left anterior, and right posterior directions at the equivalent velocity of 6 Hz shaking was simulated. The violent shaking frequency of the adult male was 3.2-6.8 Hz; head shaking at these frequencies could result in serious cerebral injuries. SAS-related injuries have obvious directionality, and sagittal shaking can easily cause brain injuries. There was no significant difference between the brain injuries caused by shaking in the simulated frequency range (4-7 Hz). Impact and shaking at an equivalent velocity could cause brain injuries, though SAS more commonly occurred due to the cumulative deformation of brain tissue. Biomechanical studies of SAS should play a positive role in improving the accuracy of forensic identification and reducing this form of abuse and torture in detention or places of imprisonment.

Dental age estimation of Tibetan children and adolescents: Comparison of Demirjian, Willems methods and a newly modified Demirjian method.

Tibetan ethnic group is one of the oldest ethnic groups in China and South Asia. This study set out to analyze the dental development and validate Demirjian method and Willems method in estimating dental age of Tibetan children and adolescents, and to modify Demirjian method based on Tibetan population to provide ethnic-specific reference data and a more reliable method for forensic age assessment in Tibetan ethnic group. In this study, 1951 samples aged between 4 and 15 years were retrospectively collected and analyzed. Multiple linear regression was used to establish relationship between chronological age (CA) and developmental stages of left mandibular permanent teeth. The accuracy of the modified method was tested and compared with that of Demirjian and Willems method. Results showed that dental maturity score (DMS) was significantly greater in girls than in boys in all age groups except for the 4-year age group (p < 0.05). Mean absolute error (MAE) was 0.96 years for both boys and girls by Demirjian method, and 1.06 and 1.16 years for boys and girls respectively by Willems method. Adjusted scores table was established and tested. The age of boys was overestimated by 0.13 years and the age of girls was underestimated by 0.06 years by the adjusted scores table. MAE was lower than that of the other two methods. In conclusion, Demirjian method and Willems method was not sufficiently accurate in estimating dental age of Tibetan population. The modified method was more suitable for dental age estimation of Tibetan population than Demirjian and Willems method.

Postmortem chest computed tomography for the diagnosis of drowning: a feasibility study.

It may be difficult to distinguish the cause of death in drowning cases without specific findings. The aim of this study was to explore the forensic value of thoracic postmortem computed tomography (PMCT) using routine images and three-dimensional (3D) image reconstructions. The imaging data of PMCT examinations of six drowning cadavers, aged 21-54 years, were analyzed. Twelve victims of sudden death from coronary artery disease (CAD) were chosen as a control group. After 3D bilateral lung images were reconstructed using image processing software, an interactive medical image control system was used to measure and analyze parameters including lung volume, lung volume ratio, mean CT value of the whole lung, and lung CT value distribution curves. Lung volume and lung volume ratio were used to assess the shape changes of the lung. Lung CT value distribution curves showed the corresponding number of pixels of the different CT values in the lung image. Lung volume was not significantly larger in drowning cases (mean 2 958 cm3) than in controls (mean 2 342 cm3). Lung volume ratio values in the drowning group (mean 0.3156) were greater than those in the control group (mean 0.2763); (P = 0.02). There was no significant difference between the drowning and control group in the mean CT value of the whole lung. There were differences between lung CT value distribution curves in drowning victims and controls, with drowning victims showing a single peak and CAD cases showing a bimodal distribution. Thoracic PMCT is helpful for the forensic medical diagnosis of drowning. Lung volume ratio and lung CT value distribution are potential indicators to distinguish between drowning and CAD.

Diagnosis of Vascular Rupture Due to Arteriovenous Malformation Using Postmortem Angiography and 3-Dimensonal Printing: A Case Report.

ABSTRACT: Postmortem computed tomography (PMCT), PMCT angiography, and 3-dimensonal (3D) printing technology are increasingly applied to forensic practice. Although their effectiveness is undeniably confirmed, their potential role in practice still needs to be further explored. Here, we report a typical case in which such 4 technologies were applied to a woman found dead with stomach content beneath the head on the pillow in her residence. At first, the cause of death was simply considered as hypertensive cerebral hemorrhage after preliminary examination. However, the initial judgment was questioned by her family for her devoid of hypertension history. As indicated by the targeted PMCT with cerebral angiography, the woman died of pathological cerebral hemorrhage due to arteriovenous malformation, which was still unconvincing enough for the family because in violent death, some cerebral hemorrhage could also be located in the same position. Finally, the family came to be convinced when the close connection between the deformed blood vessels and hematoma was perfectly demonstrated by the application of 3D printing technology. This study proved that it can be an efficient tool for identifying the cause of death when the integration is made of 3D printing technology and PMCT angiography, as a more intuitive evidence of forensic science.

A potential method for sex estimation of human skeletons using deep learning and three-dimensional surface scanning.

Deep learning based on radiological methods has attracted considerable attention in forensic anthropology because of its superior classification capacities over human experts. However, radiological instruments are limited in their nature of high cost and immobility. Here, we integrated a deep learning algorithm and three-dimensional (3D) surface scanning technique into a portable system for pelvic sex estimation. Briefly, the images of the ventral pubis (VP), dorsal pubis (DP), and greater sciatic notch (GSN) were cropped from virtual pelvic samples reconstructed from CT scans of 1000 individuals; 80% of them were used to train and internally evaluate convolutional neural networks (CNNs) that were then evaluated externally with the remaining samples. An additional 105 real pelvises were documented virtually with a handheld 3D surface scanner, and the corresponding snapshots of the VP, DP, and GSN were predicted by the trained CNN models. The CNN models achieved excellent performance in the external testing using CT-based images, with accuracies of 98.0%, 98.5%, and 94.0% for VP, DP, and GSN, respectively. When the CT-based models were applied to 3D scanning images, they obtained satisfactory accuracies above 95% on the VP and DP images compared to the GSN with 73.3%. In a single-blind trial, a multiple design that combined the three CNN models yielded a superior accuracy of 97.1% with 3D surface scanning images over two anthropologists. Our study demonstrates the great potential of deep learning and 3D surface scanning for rapid and accurate sex estimation of skeletal remains.

Current state and progress of research on forensic biomechanics in China.

Forensic biomechanics gradually has become a significant component of forensic science. Forensic biomechanics is evidence-based science that applies biomechanical principles and methods to forensic practice, which has constituted one of the most potential research areas. In this review, we introduce how finite element techniques can be used to simulate forensic cases, how injury criteria and injury scales can be used to describe injury severity, and how tests of postmortem human subjects and dummy can be used to provide essential validation data. This review also describes research progress and new applications of forensic biomechanics in China.Key pointsThe review shows the main research progress and new applications of forensic biomechanics in China.The review introduces eight cases about the application of forensic biomechanics, including the multiple rigid body reconstruction, the finite element applications, study of mechanical properties, traffic crash reconstruction based on multiple techniques and analysis of morphomechanical mechanism about blood dispersal.Though forensic biomechanics has a great advantage for the evaluation of injury mechanisms, it still has some uncertainties owing to the uniqueness of the human anatomy, the complexity of biological materials, and the uncertainty of injury-causing circumstances.

The influence of sample geometry and size on porcine aortic material properties from uniaxial tensile tests using custom-designed tissue cutters, clamps and molds.

The aim of this study was to identify the influence of specimen geometry and size on the results of aortic uniaxial tensile tests using custom-designed tissue cutters, clamps and molds. Six descending thoracic aortas from pigs were used for rectangular sample tests, in which the circumferential and axial specimens had widths of 6 mm, 8 mm and 10 mm. The other six aortas were used for the dog-bone-shaped sample tests and were punched into circumferential, axial and oblique specimens with widths of 2 mm, 4 mm and 6 mm. We performed uniaxial tensile tests on the specimens and compared the test results. The results showed that mid-sample failure occurred in 85.2% of the dog-bone-shaped specimens and in 11.1% of the rectangular samples, which could be caused by Saint-Venant's principle. Therefore, rectangular specimens were not suitable for aortic uniaxial tensile testing performed until rupture. The results also showed that the size effect of the aorta conformed to Weibull theory, and dog-bone-shaped specimens with a width of 4 mm were the optimal choice for aortic uniaxial tensile testing performed until rupture.

An efficient method for building a database of diatom populations for drowning site inference using a deep learning algorithm.

Seasonal or monthly databases of the diatom populations in specific bodies of water are needed to infer the drowning site of a drowned body. However, existing diatom testing methods are laborious, time-consuming, and costly and usually require specific expertise. In this study, we developed an artificial intelligence (AI)-based system as a substitute for manual morphological examination capable of identifying and classifying diatoms at the species level. Within two days, the system collected information on diatom profiles in the Huangpu and Suzhou Rivers of Shanghai, China. In an animal experiment, the similarities of diatom profiles between lung tissues and water samples were evaluated through a modified Jensen-Shannon (JS) divergence measure for drowning site inference, reaching a prediction accuracy of 92.31%. Considering its high efficiency and simplicity, our proposed method is believed to be more applicable than existing methods for seasonal or monthly water monitoring of diatom populations from sections of interconnected rivers, which would help police narrow the investigation scope to confirm the identity of an immersed body.

Pulmonary PMCT angiography by right ventricle cardiac puncture: a novel, promising approach for investigating pulmonary thromboembolism.

Forensic scholars are paying more attention to postmortem computed tomography (PMCT) and PMCT angiography (PMCTA), which are gradually becoming effective and practical methods in forensic practice. However, few studies have focused on the application of PMCTA to cardiac ventricular puncture-especially of the right ventricle. In this article, we introduce a pulmonary PMCTA approach by right ventricle cardiac puncture and its potential value in fatalities from pulmonary thromboembolism (PTE). The procedure was performed on 11 males and 6 females. PMCT was performed first; then a biopsy core needle was used for percutaneous puncture of the right ventricle under CT guidance. About 400 mL of contrast media was injected at a rate of 50 mL/8 s, followed by CT scanning. Visualization of the pulmonary artery contrast filling was complete in 9 cadavers, and the pulmonary arteries showed significant filling defects in 8 subjects. Unlike in clinical practice, the phenomenon of postmortem coagulation sometimes occurs in the vascular lumina after death. Therefore, the results of these 8 cases can only suggest or be highly suspicious of death from PTE. Then autopsy and histopathological examination confirmed that 4 of the above 8 patients were diagnosed with PTE; the remaining 4 had postmortem clot including chicken fat clot in the pulmonary artery. Pulmonary PMCTA approach is a simple, convenient, and effective method for the visualization of the pulmonary artery, which can be used as an effective auxiliary tool to identify PTE in forensic practice. It will also provide technical support to further investigate PTE imaging characteristics.

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.

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.

Estimation of sex based on patella measurements in a contemporary Chinese population using multidetector computed tomography: An automatic measurement method.

Sex estimation is an important part of creating a biological profile, and ultimately assisting in creating a presumptive identification of unidentified skeletal remains. However, manual methods of anthropometric are time-consuming and prone to observer variability. The present study is an attempt to estimation of sex from automatic measurement of patella by multidetector computed tomography (MDCT) in a contemporary Chinese population. Four measurements for every patella, including maximum height (MAXH), maximum breadth (MAXB), maximum thickness (MAXT) and patellar volume (PV), were automatically provided by the software from CT image of 300 Chinese. The sample is composed of 156 males and 144 females with an average age of 41.44 and 45.68 years, respectively. The statistical analyses showed that all variables were sexually dimorphic. Receiver operating characteristic (ROC) analysis was performed to estimate sex from patella. The univariate analysis of each patellar parameter yielded a sex classification accuracy rate of 73.1% to 85.7%. The classification accuracy rates of sex estimation using the combination of the patellar parameters are 81.9% to 91.6%. This paper provides indications that the patella is important bone for sex estimation and it may be used as an alternative in forensic cases when the skull and pelvis are unavailable.

Finite element analysis to determine the cause of ring fractures in a motorcyclist's head.

The finite element (FE) method can potentially help in reconstructing skull fracture biomechanisms, enabling differentiation of the injury patterns caused by traffic accidents. This study aims to (1) reconstruct a motorcycle driver-car accident case using the total human model for safety and FE simulations; and (2) analyze the biomechanisms of fatal ring fractures in the motorcyclist's skull base to determine if the fatal craniocerebral injuries were caused by a fall onto the highway after hitting a pedestrian or by the subsequent impact of a car. We simulated a series of loading scenarios of falls onto the road and impacts by a car, with and without a helmet being used. We reconstructed the injury processes and compared the biomechanics results to the skull tolerance limit. For the scenario of falling with a helmet, the Von-Mises stress around the foramen magnum indicated ring fractures with a slight fracture at the impact site, consistent with that detected in a traditional forensic pathology autopsy. Moreover, we found that a helmet can significantly protect the skull by controlling the increase in stress around the impact site. However, it has very little effect on the skull base, neck, or cervical spine. We determined that the characteristic ring fracture was most probably caused by the fall onto the highway. Thus, the subsequent car accident did not contribute to the motorcyclist's death. Our study demonstrates that the FE model and method can explore injury biomechanisms, assisting in the identification of injury patterns in forensic practices.

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.