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.

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.

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.

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.

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.

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.

Quantitative analysis of noncoding RNA from paired fresh and formalin-fixed paraffin-embedded brain tissues.

Formalin-fixed paraffin-embedded (FFPE) tissues are commonly used both clinically and in forensic pathology. Recently, noncoding RNA (ncRNA) has attracted interest among molecular medical researchers. However, it remains unclear whether newly identified ncRNAs, such as long noncoding RNA (lncRNA) and circular RNA (circRNA), remain stable for downstream molecular analysis in FFPE tissues. Here, we assessed the feasibility of using autoptic FFPE brain tissues from eight individuals to perform quantitative molecular analyses. Selected RNA targets (9 mRNAs and 15 ncRNAs) with different amplicon lengths were studied by RT-qPCR in paired fresh and FFPE specimens. For RNA quality assessment, RNA purity and yield were comparable between the two sample cohorts; however, the RNA integrity number decreased significantly during FFPE sampling. Amplification efficiency also displayed certain variability related with amplicon length and RNA species. We found molecular evidence that short amplicons of mRNA, lncRNA, and circRNA were amplified more efficiently than long amplicons. With the assistance of RefFinder, 5S, SNORD48, miR-103a, and miR-125b were selected as reference genes given their high stability. After normalization, we found that short amplicon markers (e.g., ACTB mRNA and MALAT1 lncRNA) exhibited high consistency of quantification in paired fresh/FFPE samples. In particular, circRNAs (XPO1, HIPK3, and TMEM56) presented relatively consistent and stable expression profiles in FFPE tissues compared with their corresponding linear transcripts. Additionally, we evaluated the influence of prolonged storage time on the amplification of gene transcripts and found that short amplicons still work effectively in archived FFPE biospecimens. In conclusion, our findings demonstrate the possibility of performing accurate quantitative analysis of ncRNAs using short amplicons and standardized RT-qPCR assays in autopsy-derived FFPE samples.

Three-Dimensional Printing Technology Combined With Postmortem Computed Tomography Angiography as New Form of Forensic Evidence: A Case Report.

Postmortem computed tomography (PMCT) and PMCT angiography are increasingly used in forensic practice. However, their application in court is still limited because they need professional equipment or software to be displayed. In this article, the authors introduce 3-dimensional (3D) printing technology as a new approach to provide evidence in court. A 67-year-old woman suffered from severe sick sinus syndrome, and she was fitted with a ventricular demand inhibited pacemaker. The operation failed as the doctor accidentally perforated her heart with an electrode wire. Her heart stopped beating, and she died after the operation. Targeted PMCT with pulmonary artery angiography was performed after the body was dissected, and a model of the heart was reconstructed using 3D printing technology, with different colored materials. The results confirmed by the autopsy suggested that the victim had died of cardiac rupture. The apex close to the right margin of the heart showed a tiny cleft where the contrast agent was flowing out. The heart model was an effective way to interpret this medical injury. This 3D printing technology, combined with PMCT angiography, provides a convenient, efficient tool for identifying the cause of death. It could become a powerful form of court evidence in the future.

Postmortem diagnosis of fatal hypothermia/hyperthermia by spectrochemical analysis of plasma.

Postmortem diagnosis of extreme-weather-related deaths is a challenging forensic task. Here, we present a state-of-the-art study that employed attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy in combination with Chemometrics for postmortem diagnosis of fatal hypothermia/hyperthermia by biochemical investigation of plasma in rats. The results of principal component analysis (PCA) and spectral analysis revealed that plasma samples from the fatal hypothermia, fatal hyperthermia, and control groups, are substantially different from each other based on the spectral variations associated with the lipid, carbohydrate and nucleic acid components. Two partial least squares-discriminant analysis (PLS-DA) classification models (hypothermia-nonhypothermia and hyperthermia-nonhyperthermia binary models) with a 100% accuracy rate were constructed. Subsequently, internal cross-validation was performed to assess the robustness of these two models, which resulted in 98.1 and 100% accuracy. Ultimately, classification predictions of 42 unknown plasma samples were performed by these two models, and both models achieved 100% accuracy. Additionally, our results demonstrated that hemolysis and postmortem hypothermic/hyperthermic effects did not weaken the prediction ability of these two classification models. In summary, this work demonstrates ATR-FTIR spectroscopy's great potential for postmortem diagnosis of fatal hypothermia/hyperthermia.

Identification of Pulmonary Edema in Forensic Autopsy Cases of Sudden Cardiac Death Using Fourier Transform Infrared Microspectroscopy: A Pilot Study.

Many studies have proven the usefulness of biofluid-based infrared spectroscopy in the clinical domain for diagnosis and monitoring the progression of diseases. Here we present a state-of-the-art study in the forensic field that employed Fourier transform infrared microspectroscopy for postmortem diagnosis of sudden cardiac death (SCD) by in situ biochemical investigation of alveolar edema fluid in lung tissue sections. The results of amide-related spectral absorbance analysis demonstrated that the pulmonary edema fluid of the SCD group was richer in protein components than that of the neurologic catastrophe (NC) and lethal multiple injuries (LMI) groups. The complementary results of unsupervised principle component analysis (PCA) and genetic algorithm-guided partial least-squares discriminant analysis (GA-PLS-DA) further indicated different global spectral band patterns of pulmonary edema fluids between these three groups. Ultimately, a random forest (RF) classification model for postmortem diagnosis of SCD was built and achieved good sensitivity and specificity scores of 97.3% and 95.5%, respectively. Classification predictions of unknown pulmonary edema fluid collected from 16 cases were also performed by the model, resulting in 100% correct discrimination. This pilot study demonstrates that FTIR microspectroscopy in combination with chemometrics has the potential to be an effective aid for postmortem diagnosis of SCD.

Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectral prediction of postmortem interval from vitreous humor samples.

Evaluation of postmortem interval (PMI) is of paramount importance to guide criminal investigations, especially when witnesses are not found. However, accurate PMI estimation is a challenging task in the forensic community due to the limitations of existing methods. The study aims to investigate the potential of attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy for predicting PMI based on vitreous humor (VH). VH samples were collected from 72 rabbits in the range of 0-48 h postmortem at a 6-h interval. Their FTIR spectra were normalized by the extended multiplicative signal correction (RMSC) and divided into calibration and validation sets. After analysis of the absorption bands, the Bayesian ridge regression (BRR), support vector regression (SVR), and artificial neural network (ANN) methods were established by the calibration set using a 10-fold cross-validation that was further used to predict the PMI in the validation set. The validity of the models was assessed by a permutation test. The current study demonstrated that multiple macromolecules in the VH samples were reflected in a FTIR spectrum, and the spectral absorption bands at 1313 and 925 cm-1 were highly correlated with PMI. The three models allowed generalization to the validation set due to similar R2 and errors between the calibration and validation tests. The highest accuracy with R2 = 0.983 and error = 2.018 h was achieved by the ANN model in the validation test. The results suggest that ATR-FTIR spectroscopy may be useful for VH analysis in order to predict PMI in the future. Graphical abstract ᅟ.

Subtentorial Meningioma Misdiagnosed as Cerebral Hemorrhage in Postmortem Computed Tomography Imaging: A Case Report.

This report presents a case of a 52-year-old man who had a traffic accident and died later. External examination could not determine the cause of death. Approximately 3 weeks later, an autopsy was performed. Postmortem computed tomography was performed before the autopsy. Postmortem imaging was interpreted to show hemorrhage beneath the tentorium, and the C5 to C6 (the fifth and sixth cervical vertebra) disc space was widened. During the autopsy, a cervical spinal cord injury was confirmed. However, a meningioma was found under the tentorium instead of a hemorrhage. There are a number of reasons that include postmortem changes that affected the virtopsy diagnosis, which still needs development.

Detection of aortic rupture using post-mortem computed tomography and post-mortem computed tomography angiography by cardiac puncture.

Post-mortem computed tomography (PMCT) and post-mortem computed tomography angiography (PMCTA) are rapidly becoming effective and practical methods in forensic medicine. In this article, we introduce a PMCTA approach by cardiac puncture and its application in a specific forensic case. A 50-year-old female sanitation worker was found dead on a road. External examination of the body revealed scattered abrasions and contusions over the chest. Autopsy was refused by the family members, and the body was examined with PMCT and PMCTA by cardiac puncture. Sternal fracture and rib fractures were detected by PMCT and aortic rupture by PMCTA. The cause of death was hemorrhagic shock due to traumatic aortic rupture. In certain circumstances, the combination of PMCT and PMCTA is helpful for forensic pathologists to determine the cause of death in cases involving traumatic vascular injury.

Application of Microbeam X-Ray Fluorescence Spectrometry in the Diagnosis of Suspected Electrocution by High-Voltage Direct Current: A Case Report.

Electrocution cases reported in the literature were mainly caused by low-voltage alternating current, with few cases associated with high-voltage direct current. In this article, we report the case of a 48-year-old woman who unexpectedly and suddenly died in the wild because of electric shock by a high-voltage direct current while hunting. The postmortem inspection found a suspected current mark on her right upper thigh, and histological examination of the suspected current mark revealed a slight elongation of the epidermal cell nuclei and separation of the corneous layer. Metal elements analysis by microbeam x-ray fluorescence spectrometry demonstrated a peak concentration of iron in the suspected current-injured skin surface, which was in line with the metal wire at the scene. In addition, the deceased had coronary atherosclerotic heart disease, which can increase the body's risk to the current damage. Our results indicated the usefulness of microbeam x-ray fluorescence spectrometry for the forensic diagnosis of electrocution.

Sudden Death Due to Cerebral Leukemic Hemorrhage in a 32-Year-Old Woman Who Had a Short-Term Benzene Exposure History.

Acute myeloid leukemia (AML), also known as acute myelogenous leukemia, is associated with severe hemorrhagic coagulopathy, which is induced by the drop in red blood cells, platelets, and normal leukocyte and the increase of leukemic cells. The case described in this report was of a 32-year-old woman who unexpectedly and suddenly died because of cerebral hemorrhage caused by undiagnosed AML while hospitalized. Further investigation found that the decedent had been exposed to benzene and its derivatives 6 months before her death. This case suggests that underlying AML should be considered as a possible diagnosis when sudden death occurs with a fatal spontaneous intracerebral hemorrhage, especially if the deceased had occupational chemical exposure to benzene and its derivatives.

Diagnosis of a Cerebral Arteriovenous Malformation Using Isolated Brain Computed Tomography Angiography: Case Report.

This report presents a case of a 40-year-old woman who was found dead in her house. The examination of the body revealed no external injuries. The whole body was scanned by multi-detector-row computed tomography (CT) before autopsy, revealing massive hemorrhage in the right frontal extending into the ventricular system. At autopsy, the brain parenchyma was removed. Then CT angiography was carried on the isolated brain. Computed tomography angiography suggested a mass of irregular, tortuous vessels in areas of hemorrhage in the right frontal lobe of the brain. Finally, histological examination confirmed the result of CT angiography due to an arteriovenous malformation. Hence, postmortem CT angiography played an important role in diagnosis of the cerebral arteriovenous malformation that was responsible for a massive hemorrhage in the skull.