Comparison of CT Values between Thrombus and Postmortem Clot Based on Cadaveric Pulmonary Angiography / 法医学杂志

OBJECTIVES@#To explore the difference in CT values between pulmonary thromboembolism and postmortem clot in postmortem CT pulmonary angiography (CTPA) to further improve the application value of virtual autopsy.@*METHODS@#Postmortem CTPA data with the definite cause of death from 2016 to 2019 were collected and divided into pulmonary thromboembolism group (n=4), postmortem clot group (n=5), and control group (n=5). CT values of pulmonary trunk and left and right pulmonary artery contents in each group were measured and analyzed statistically.@*RESULTS@#The average CT value in the pulmonary thromboembolism group and postmortem clot group were (168.4±53.8) Hu and (282.7±78.0) Hu, respectively, which were lower than those of the control group (1 193.0±82.9) Hu (P<0.05). The average CT value of the postmortem clot group was higher than that of the pulmonary thromboembolism group (P<0.05).@*CONCLUSIONS@#CT value is reliable and feasible as a relatively objective quantitative index to distinguish pulmonary thromboembolism and postmortem clot in postmortem CTPA. At the same time, it can provide a scientific basis to a certain extent for ruling out pulmonary thromboembolism deaths.

Strategies for Collection and Analysis of Samples in Simple Asphyxiant Gas Acute Poisoning Death Cases / 法医学杂志

At present, the death cases of simple asphyxiant gas acute poisoning are increasing sharply. Common asphyxiant gases in death cases include nitrogen, helium, carbon dioxide, methane, propane, laughing gas, etc. Simple asphyxiant gas has no affinity for biological matrices and escapes quickly, which puts forward new requirements for autopsy procedures, selection and collection of samples, laboratory analysis and identification. This paper reviews the research and development process of death cases caused by simple asphyxiant gas acute poisoning and put forwards the collection and analysis strategy of the samples in such cases. The most valuable biological samples in such cases should be lung tissues associated with the airways, followed by brain tissue and cardiac blood. Gaseous samples from the esophageal cavity, tracheal cavity, pulmonary bronchi, gastric and cardiac areas are also recommended as valuable samples. In the case of postmortem examination, the gas should be injected into gas sample bag directly. Biological materials such as tissue and blood should be directly sealed in head-space vials and analyzed by using the headspace gas chromatography-mass spectrometry.

Automatic Identification of Brain Injury Mechanism Based on Deep Learning / 法医学杂志

OBJECTIVES@#To apply the convolutional neural network (CNN) Inception_v3 model in automatic identification of acceleration and deceleration injury based on CT images of brain, and to explore the application prospect of deep learning technology in forensic brain injury mechanism inference.@*METHODS@#CT images from 190 cases with acceleration and deceleration brain injury were selected as the experimental group, and CT images from 130 normal brain cases were used as the control group. The above-mentioned 320 imaging data were divided into training validation dataset and testing dataset according to random sampling method. The model classification performance was evaluated by the accuracy rate, precision rate, recall rate, F1-value and AUC value.@*RESULTS@#In the training process and validation process, the accuracy rate of the model to classify acceleration injury, deceleration injury and normal brain was 99.00% and 87.21%, which met the requirements. The optimized model was used to test the data of the testing dataset, the result showed that the accuracy rate of the model in the test set was 87.18%, and the precision rate, recall rate, F1-score and AUC of the model to recognize acceleration injury were 84.38%, 90.00%, 87.10% and 0.98, respectively, to recognize deceleration injury were 86.67%, 72.22%, 78.79% and 0.92, respectively, to recognize normal brain were 88.57%, 89.86%, 89.21% and 0.93, respectively.@*CONCLUSIONS@#Inception_v3 model has potential application value in distinguishing acceleration and deceleration injury based on brain CT images, and is expected to become an auxiliary tool to infer the mechanism of head injury.

Logistic Regression Analysis of the Mechanism of Blunt Brain Injury Inference Based on CT Images / 法医学杂志

OBJECTIVES@#To study the correlation between CT imaging features of acceleration and deceleration brain injury and injury degree.@*METHODS@#A total of 299 cases with acceleration and deceleration brain injury were collected and divided into acceleration brain injury group and deceleration brain injury group according to the injury mechanism. Subarachnoid hemorrhage (SAH) and Glasgow coma scale (GCS), combined with skull fracture, epidural hematoma (EDH), subdural hematoma (SDH) and brain contusion on the same and opposite sides of the stress point were selected as the screening indexes. χ2 test was used for primary screening, and binary logistic regression analysis was used for secondary screening. The indexes with the strongest correlation in acceleration and deceleration injury mechanism were selected.@*RESULTS@#χ2 test showed that skull fracture and EDH on the same side of the stress point; EDH, SDH and brain contusion on the opposite of the stress point; SAH, GCS were correlated with acceleration and deceleration injury (P<0.05). According to binary logistic regression analysis, the odds ratio (OR) of EDH on the same side of the stress point was 2.697, the OR of brain contusion on the opposite of the stress point was 0.043 and the OR of GCS was 0.238, suggesting there was statistically significant (P<0.05).@*CONCLUSIONS@#EDH on the same side of the stress point, brain contusion on the opposite of the stress point and GCS can be used as key indicators to distinguish acceleration and deceleration injury mechanism. In addition, skull fracture on the same side of the stress point, EDH and SDH on the opposite of the stress point and SAH were relatively weak indicators in distinguishing acceleration and deceleration injury mechanism.

Research on the Identification Model of Medical Damage / 法医学杂志

OBJECTIVES@#To understand the perceptions of doctors, patients and forensic examiners on the current situation of medical disputes and medical damage identification in China, and to explore the medical damage identification model that is more conducive for the resolution of medical disputes.@*METHODS@#A questionnaire was designed, and in-service clinicians, forensic examiners and inpatients in Sichuan Province and Chongqing City were randomly selected from April to November 2019. SPSS 22.0 software was used to analyze the data of various survey results.@*RESULTS@#Compared with patients (24.92%), doctors (61.72%) believed that the current doctor-patient relationship was more tense than before; both doctors and patients were more inclined to choose voluntary consultation and people's mediation to resolve medical disputes; forensic examiners have the highest level of cognition of medical and health-related laws and regulations, followed by doctors and patients; 66.72% of doctors and 78.41% of patients believed that medical damage identification was necessary, and they were more inclined to entrust forensic identification institutions; different groups all believed that forensic examiners and doctors should participate in the identification together, 80.94% of doctors believed that the appraisal institutions should be responsible for the forensic opinion, not the appraiser.@*CONCLUSIONS@#It is suggested that the Medical Association identification and forensic identification should learn from each other and formulate basic unified rules for the identification of medical damage. It is suggested to standardize the behavior of medical damage forensic identification institutions and appraisers, to improve their own appraisal level, actively invite clinical medical experts for consultation in identification, and promote the standardized, scientization of forensic identification.

Virtual Autopsy Morphological Features of Drowning / 法医学杂志

OBJECTIVES@#To explore the application value of virtual autopsy to obtain key evidence information on drowned corpses and its application value of virtual autopsy in the diagnosis of drowning.@*METHODS@#In this study, 7 corpses were selected as the research objects. The image data of corpses were collected by computed tomography (CT) before conventional autopsy. The characteristics of corpses were observed through image reading, combined with virtual measurement indexes, and compared with 15 non-drowned corpses.@*RESULTS@#The postmortem CT of drowning showed the more fluid in respiratory tract than the non-drowning, and ground-glass opacities in the lung. The statistical volume of fluid in the sinus (maxillary sinus and sphenoid sinus) was (10.24±4.70) mL in drowning cases and (2.02±2.45) mL in non-drowning cases. The average CT value of fluid in the sinus, left atrial blood and gastric contents in drowning cases were (15.91±17.20), (52.57±9.24) and (10.33±12.81) HU, respectively, which were lower than those in non-drowning cases (P<0.05).@*CONCLUSIONS@#The comprehensive consideration of multiple characteristic image manifestations and the virtual measurement indexes are helpful to the forensic pathological diagnosis of drowning. Virtual autopsy can be used as an auxiliary method in the forensic diagnosis of drowning.

Deep Learning-Based Cardiac Imaging Data Measurement and Its Application in Diagnosis of Sudden Cardiac Death / 法医学杂志

In the field of forensic medicine, diagnosis of sudden cardiac death is limited by subjective factors and manual measurement methods, so some parameters may have estimation deviation or measurement deviation. As postmortem CT imaging plays a more and more important role in the appraisal of cause of death and cardiopathology research, the application of deep learning such as artificial intelligence technology to analyze vast amounts of cardiac imaging data has provided a possibility for forensic identification and scientific research workers to conduct precise diagnosis and quantitative analysis of cardiac diseases. This article summarizes the main researches on deep learning in the field of cardiac imaging in recent years, and proposes a feasible development direction for the application of deep learning in the virtual anatomy of sudden cardiac death at present.

Research Progress of Zebrafish Model in Toxicology and Its Application Prospects in Forensic Science / 法医学杂志

In recent years, zebrafish model has been widely concerned and recognized by scholars at home and abroad. As an animal model, zebrafish is of great research value because it is easy to feed, easy to operate, observe and analyze, and the model results can be highly combined with human body test data. Zebrafish model has been widely used in many fields, including basic medical science, clinical medicine, agricultural production, environmental toxicology and forensic science. This review introduces the biological characteristics of zebrafish, summarizes the research progress of zebrafish model in toxicology, and discusses the application prospect of zebrafish model in forensic science.

Research Status of Postmortem MSCT Angiography in Forensic Science / 法医学杂志

Virtual autopsy is a new technique for investigating the morphological changes of cadaveric tissues and organs by medical imaging technology. It has been widely used in the identification of causes of death. Multislice spiral computed tomography （MSCT） has become a routine inspection method in some identification institutions, although it cannot completely replace traditional autopsy, it plays a key auxiliary or substitute role in the identification of certain abnormal causes of death. Plain MSCT scan cannot visualize cadaveric vessels, but can perform cadaveric angiography to determine vascular injury or disease. This technology has entered a rapid development period in recent years, and has made a considerable progress in contrast agent, perfusion methods and imaging methods. This article summarizes several common cadaveric MSCT angiography methods, such as systemic angiography, angiography through cardiopulmonary resuscitation, targeted angiography, and angiography by cardiac puncture, and analyzes and compares the application prospects.

Research Progress of Metabolomics in Forensic Pathology / 法医学杂志

Metabolomics is an interdisciplinary subject that rose in the post-genomic era, which focuses on quantitative study of the response of living organisms to outside stimulation and pathophysiological changes, as well as multiple dynamic response of the level of in vivo metabolites caused by genetic mutation. It is extensively used in basic research of system biology, materia medica, clinical medicine, etc. In the forensic field, metabolomics mainly focuses on forensic toxicology, but with the generalization of certain techniques, it's foreseeable that metabolomics has a broad research prospect in forensic pathology. This article summarizes the major analysis techniques and methods of metabolomics, describes the research status of metabolomic techniques in the field of forensic pathology application research, including postmortem interval and death cause. Moreover, this article summarizes and discusses the potential applicable areas, in order to provide reference for relative research and application.

Application of Virtual Anatomy Technology in Postmortem Examination of Medical Dispute Cases / 法医学杂志

Objective To discuss the application value of CT scanning technology in cause of death determination of medical dispute cases. Methods From July 2017 to December 2018, postmortem CT imaging data of 12 medical dispute cases were collected. CT imaging diagnosis results and anatomy findings as well as differences between antemortem and postmortem CT diagnosis were compared. The advantages and disadvantages of CT routine tests of the cadavers in terms of the diagnosis of disease and damage were analyzed. Results The comparison between CT imaging diagnosis and anatomical findings showed that CT scans had advantages in the diagnosis of disease and damage with large differences in density changes, such as atelectasis, pneumonia, calcification, fracture and hemorrhage, etc. The comparison of CT diagnosis in antemortem and postmortem examination showed that the cadavers of medical dispute cases were well preserved and that postmortem CT scan was meaningful for the diagnosis of antemortem diseases. Conclusion Virtual anatomy technology has a relatively high application value in postmortem examination of medical dispute cases. It can provide effective information for the appraisers before the autopsy and can also provide a reference for cause of death analysis when the anatomy cannot be performed.

Research Progress on Postmortem Changes of Computed Tomography Imaging Characteristics on Corpses / 法医学杂志

Postmortem changes on corpses appear immediately after death, and can transform the original structure characteristics of the corpse to different degrees as well as show specific changes on computed tomography （CT） images, sometimes with false positives and false negatives, influencing the identification of injuries or diseases. This paper systematically summarizes the postmortem changes of computed tomography imaging characteristics on corpses, to further expand the application of virtopsy in the practices of forensic pathology identification, and provide reference for the identification of injuries, diseases and changes after normal death.

Research Progress in Virtopsy of Drowning / 法医学杂志

Dead bodies found in the water are not all caused by drowning. The important task of forensic identification is to distinguish between entering the water before and after death, and to clarify the cause of death. In the practice of forensic identification, drowning is generally diagnosed on the basis of comprehensive considerations such as cadaveric signs, histopathological examinations, and diatom tests, with the exclusion of other causes of death. The emergence of virtopsy techniques provides new insights for the diagnosis of drowning. This paper reviews the post-mortem imaging studies of sinus and mastoid small chambers, respiratory tracts, lung tissues, gastrointestinal tracts and blood in the corpses in recent years. The value, potential of virtopsy in the diagnosis of drowning is discussed, with the prospects of its development direction.

Research Progress on Detection Methods of Amphetamines in Human Hair / 法医学杂志

Amphetamines are chemical synthetic drugs that are becoming increasingly popular in China. As a common sample in the inspection of poisons, hair has the advantages of easy storage, good stability, and long detection time compared with traditional human body fluid samples （blood, urine）, thus possesses an unique application value in the field of forensic toxicology analysis. By now, methods for detecting amphetamines in human hair have been widely used, and validity of the results has been recognized and adopted by the court. This paper reviews domestic and foreign research progress of the detection of amphetamines in hair samples, including the pretreatment and analytic methods.

Analysis of Forensic Sciences Literature in SCIE from 2008 to 2017 / 法医学杂志

OBJECTIVES@#To analyze the literature on forensic sciences indexed in Science Citation Index Expanded （SCIE） in recent 10 years, and to understand the research status, characteristics and trends in the field of forensic sciences.@*METHODS@#Literature on forensic sciences from 2008 to 2017 in Web of Science （WoS） was retrieved. The documents number and geographical distribution, document types, source titles, organizations, research areas, authors, funding agencies, and the high cited articles were detected. The impact factors （IF） of journals were retrieved in Journal Citation Reports （JCR）. The data were analyzed with descriptive statistics.@*RESULTS@#From 2008 to 2017, there were 21 001 documents on forensic sciences in SCIE. The main document type was articles, with English as the major language. With regards to research areas, pathology has the largest number of papers worldwide, and genetics and heredity has the largest number of publications in mainland China. Among the 18 journals where the documents was published, Forensic Science International ranks the first on publication count, and Forensic Science International Genetics has the highest IF （5.637） in the JCR 2017. In 2017, the number of papers from mainland China increased by 48.50% compared with 2016, which was higher than the global increase （32.63%） and the top-5 countries in terms of number of publications （the US, Germany, the UK, Australia, Italy）. The average document count per organization is 1.98 worldwide and 1.17 in mainland China, respectively. The publication number per author is 0.53 worldwide and 0.36 in mainland China, respectively. Around 28.17% of the publications were funded, with National Natural Science Foundation of China （NSFC） as the Top 1 funding agency （192 papers）. Among the documents with citations, the most cited publication has been cited for 366 times.@*CONCLUSIONS@#The yearly numbers of publications on forensic sciences are increasing during recent 10 years. Focusing on the mainland China, there would be more high-quality papers with the steady funding of NSFC.

Characteristic Changes and 3D Virtual Measurement of Lung CT Image Parameters in the Drowning Rabbit Model / 法医学杂志

OBJECTIVES@#To use virtual anatomy technique in the analysis of post-mortem characteristic changes of CT images in the experimental drowning rabbit model and the related parameters in 3D virtual model, so as to explore its application value in the diagnosis of drowning in forensic pathology.@*METHODS@#A model of drowning rabbits was established, with animal models of hemorrhagic shock and mechanical asphyxia as the controls. CT scan was performed on the experimental animals, and the differences in imaging features between the groups were compared by morphological reading of the tomographic images. CT data were imported into Mimics 14.0 software for 3D modeling. The CT values and lung volumes were calculated by the software, and the differences on CT values and lung volumes brought by different causes of death were analyzed.@*RESULTS@#The CT images of lungs in the drowning group showed characteristic ground-glass opacity （diffuse and uniform density increase）. There were no obvious abnormalities in hemorrhagic shock group, and only a few similar changes were found in the mechanical asphyxia group. Compared with the controls, the CT values and the lung volumes in the drowning group were significantly increased P<0.05.@*CONCLUSIONS@#Based on post-mortem lung imaging, the combination of CT value and lung volume changes can effectively reflect the virtual anatomical features in drowning, and provide a diagnostic basis for the forensic identification of drowning.

Infrared Spectral Characteristics of Electrical Injuries on Swine Skin Caused by Different Voltages Based on Machine Learning Algorithms / 法医学杂志

Objective To explore infrared spectrum characteristics of different voltages induced electrical injuries on swine skin by using Fourier transform infrared-microspectroscopy (FTIR-MSP) combined with machine learning algorithms, thus to provide a reference to the identification of electrical skin injuries caused by different voltages.Methods Electrical skin injury model was established on swines.The skin was exposed to 110 V, 220 V and 380 V electric shock for 30 s and then samples were took, with normal skin tissues around the injuries as the control.Combined with the results of continuous section HE staining, the FTIR-MSP spectral data of the corresponding skin tissues were acquired.With the combination of machine learning algorithms such as principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA), different spectral bands were selected (full band 4 000-1 000 cm-1and sub-bands 4 000-3 600 cm-1, 3 600-2 800 cm-1, 2 800-1 800 cm-1, and 1 800-1 000 cm-1), and various pretreatment methods were used such as orthogonal signal correction (OSC), standard normal variables (SNV), multivariate scatter correction (MSC), normalization, and smoothing.Thus, the model was optimized, and the classification effects were compared.Results Compared with simple spectrum analysis, PCA seemed to be better at distinguishing electrical shock groups from the control, but was not able to distinguish different voltages induced groups.PLS-DA based on the 3 600-2 800 cm-1band was used to identify the different voltages induced skin injuries.The OSC could further optimize the robustness of the 3 600-2 800 cm-1band model.Conclusion It is feasible to identify electrical skin injuries caused by different voltages by using FTIR-MSP technique along with machine learning algorithms.

Analysis of Differentially Expressed Proteins Distribution in the Rat Brains with DAI by MALDI-TOF-IMS / 法医学杂志

OBJECTIVES@#To establish the imaging mass spectrometry for analysis of differentially expressed proteins distribution in the rat brains with diffuse axonal injury （DAI） based on matrix assisted laser desorption/ionization-time of flight imaging mass spectrometry （MALDI-TOF-IMS）.@*METHODS@#MALDI-TOF-IMS scanning were conducted on the brains of DAI group and control group in the m/z range of 1 000 to 20 000 using AutoflexⅢ MALDI-TOF spectrometer. ClinProTool 2.2 software was used for statistical analysis on the data of two groups, and then the differentially expressed proteins were picked out to conduct imaging. The distribution of the proteins with different m/z in the rat brains was observed.@*RESULTS@#Five proteins with different m/z, including 4 963, 5 634, 6 253, 6 714 and 7 532, differentially expressed in the rat brains with DAI.@*CONCLUSIONS@#MALDI-TOF-IMS can be used for studying the differentially expressed proteins in rat brains with DAI and the analysis method is established for exploring the distribution of differentially expressed proteins in the rat brains with DAI using imaging mass spectrometry.

New Progress of MALDI-TOF-IMS in the Study of Proteomics / 法医学杂志

Matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF-IMS) has been a classical technique for studying proteomics in present and a tool for analyzing the distribution of proteins and small molecules within biological tissue sections. MALDI-TOF-IMS can analyze multiple unknown compounds in biological tissue sections simultaneously through a single measurement which can obtain molecule imaging of the tissue while maintaining the integrity of cellular and molecules in tissue. In recent years, imaging mass spectrometry technique develops relatively quickly in all biomedical domain. This paper based on the relevant data and reviews the present developing level of MALDI-TOF-IMS, the principle of imaging mass spectrometry, methology and the prospect in forensic pathology.

Determination of a Newborn with Lethal Type II Osteogenesis Imperfecta and Other Anomalies Using Autopsy and Postmortem MSCT--A Case Report / 法医学杂志

A case of a stillbirth with lethal type II osteogenesis imperfecta (OI) was reported. The fetus had skull fractures and craniocerebral injuries during pregnancy. Postmortem multi-sliced computed tomography (MSCT) and 3D-reconstruction were performed, followed by a medico-legal autopsy. The autopsic findings showed the typical features of type II OI, including a soft calvarium, deformed extremities, flexed and abducted hips, and uncommon features, such as white sclera, coxa vara, absence of several bones and organs, a cleft lip, and asymmetric ears. The radiologic images revealed such anomalies and variations as a cleft palate, mandibular dysplasia, spina bifida, costa cervicalis, and fusion of the ribs and vertebrae, which were difficult to detect during conventional autopsy. The paper investigated the classification, causative mutation, cause of death, and the differentiation of OI from child abuse, coming to a conclusion that OI knowledge can be of great importance to forensic pathologists and that the merits of postmortem MSCT should be emphasized in forensic pathologic examinations.