Estimation of ancestry from cranial measurements based on MDCT data acquired in a Japanese and Western Australian population.

The estimation of ancestry is important not only towards establishing identity but also as a required precursor to facilitating the accurate estimation of other attributes such as sex, age at death, and stature. The present study aims to analyze morphological variation in the crania of Japanese and Western Australian individuals and test predictive models based on machine learning for their potential forensic application. The Japanese and Western Australian samples comprise computed tomography (CT) scans of 230 (111 female; 119 male) and 225 adult individuals (112 female; 113 male), respectively. A total of 18 measurements were calculated, and machine learning methods (random forest modeling, RFM; support vector machine, SVM) were used to classify ancestry. The two-way unisex model achieved an overall accuracy of 93.2% for RFM and 97.1% for SVM, respectively. The four-way sex and ancestry model demonstrated an overall classification accuracy of 84.0% for RFM and 93.0% for SVM. The sex-specific models were most accurate in the female samples (♀ 95.1% for RFM and 100% for SVM; ♂91.4% for RFM and 97.4% for SVM). Our findings suggest that cranial measurements acquired in CT images can be used to accurately classify Japanese and Western Australian individuals into their respective population. This is the first study to assess the feasibility of ancestry estimation using three-dimensional CT images of the skull.

Estimation of population affinity using proximal femoral measurements based on computed tomographic images in the Japanese and western Australian populations.

The present study analyzes morphological differences femora of contemporary Japanese and Western Australian individuals and investigates the feasibility of population affinity estimation based on computed tomographic (CT) data. The latter is deemed to be of practical importance because most anthropological methods rely on the assessment of aspects of skull morphology, which when damaged and/or unavailable, often hampers attempts to estimate population affinity. The study sample comprised CT scans of 297 (146 females; 151 males) Japanese and 330 (145 females; 185 males) Western Australian adult individuals. A total of 10 measurements were acquired in two-dimensional CT images of the left and right femora; two machine learning methods (random forest modeling [RFM]) and support vector machine [SVM]) were then applied for population affinity classification. The accuracy of the two-way (sex-specific and sex-mixed) model was between 71.38 and 82.07% and 76.09-86.09% for RFM and SVM, respectively. Sex-specific (female and male) models were slightly more accurate compared to the sex-mixed models; there were no considerable differences in the correct classification rates between the female- and male-specific models. All the classification accuracies were higher in the Western Australian population, except for the male model using SVM. The four-way sex and population affinity model had an overall classification accuracy of 74.96% and 79.11% for RFM and SVM, respectively. The Western Australian females had the lowest correct classification rate followed by the Japanese males. Our data indicate that femoral measurements may be particularly useful for classification of Japanese and Western Australian individuals.

Population affinity estimation using pelvic measurements based on computed tomographic data acquired from Japanese and Western Australian populations.

The present study analyzes morphological differences in the pelvis of Japanese and Western Australian individuals and investigates the feasibility of population affinity classification based on computed tomography (CT) data. The Japanese and Western Australian samples comprise CT scans of 207 (103 females; 104 males) and 158 (78 females; 80 males) adult individuals, respectively. Following volumetric reconstruction, a total of 19 pelvic landmarks were obtained on each sample, and 11 measurements, including two angles, were calculated. Machine learning methods (random forest modeling [RFM] and support vector machine [SVM]) were used to classify population affinity. Classification accuracy of the two-way models was approximately 80% for RFM: the two-way sex-specific and sex-mixed models for SVM achieved > 90% and > 85%, respectively. The sex-specific models had higher accurate classification rates than the sex-mixed models, except for the Japanese male sample. The classification accuracy of the four-way sex and population affinity model had an overall classification accuracy of 76.71% for RFM and 87.67% for SVM. All the correct classification rates were higher in the Japanese relative to the Western Australian sample. Our data suggest that pelvic morphology is sufficiently distinct between Japanese and Western Australian individuals to facilitate the accurate classification of population affinity based on measurements acquired in CT images. To the best of our knowledge, this is the first study investigating the feasibility of population affinity estimation based on CT images of the pelvis, which appears as a viable supplement to traditional approaches based on cranio-facial morphology.

Genomic analysis of SARS-CoV-2 in forensic autopsy cases of COVID-19.

Numerous genomic analyses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been conducted, highlighting its variations and lineage transitions. Despite the importance of forensic autopsy in investigating deaths due to coronavirus disease 2019 (COVID-19), including out-of-hospital deaths, viral genomic analysis has rarely been reported due in part to postmortem changes. In this study, various specimens were collected from 18 forensic autopsy cases with SARS-CoV-2 infection. Reverse-transcription quantitative polymerase chain reaction revealed the distribution of the virus in the body, primarily in the respiratory organs. Next-generation sequencing determined the complete genome sequences in 15 of the 18 cases, although some cases showed severe postmortem changes or degradation of tissue RNA. Intrahost genomic diversity of the virus was identified in one case of death due to COVID-19. The accumulation of single-nucleotide variations in the lung of the case suggested the intrahost evolution of SARS-CoV-2. Lung of the case showed diffuse alveolar damage histologically and positivity for SARS-CoV-2 by immunohistochemical analysis and in situ hybridization, indicating virus-associated pneumonia. This study provides insights into the feasibility of genomic analysis of SARS-CoV-2 in forensic autopsy cases and the potential for uncovering important information in COVID-19 deaths, including out-of-hospital deaths.

Age estimation by evaluating median palatine suture closure using postmortem CT.

This study sought to develop an age-estimation formula to evaluate the extent of median palatine suture (MP) closure using postmortem computed tomographic (PMCT) images. The PMCT images of 634 Japanese subjects (mean age, 54.5 years; standard deviation [SD], 23.2 years) with known age and sex were examined. The degree of suture closure of the MP, anterior median palatine suture (AMP), and posterior median palatine suture (PMP) was measured and scored (suture closure score, SCS), and a single linear regression analysis was conducted with age at death. On the analysis, SCS of MP, AMP, and PMP showed a significant correlation with age (p < 0.001). The correlation coefficient of MP was higher (0.760, male; 0.803, female; and 0.779, total) than that of AMP (0.726, male; 0.745, female; and 0.735, total) or PMP (0.457, male; 0.630, female; and 0.549, total). The regression formula and standard error of estimation (SEE) of MP were calculated as Age = 100.95 × SCS + 20.51 (SEE 14.87 years) for male subjects, Age = 91.93 × SCS + 26.65 (SEE 14.12 years) for female subjects, and Age = 95.17 × SCS + 24.09 (SEE 14.59 years) for the total, respectively. In addition, another 50 Japanese subjects were randomly selected to validate the age-estimation formula. In this validation, the actual age of 36 subjects (72%) was within the estimated age ± SEE. This study showed that the age estimation formula using PMCT images of MPs was potentially useful for estimating the age of unidentified corpses.

Stature estimation by semi-automatic measurements of 3D CT images of the femur.

Stature estimation is one of the most basic and important methods of personal identification. The long bones of the limbs provide the most accurate stature estimation, with the femur being one of the most useful. In all the previously reported methods of stature estimation using computed tomography (CT) images of the femur, laborious manual measurement was necessary. A semi-automatic bone measuring method can simplify this process, so we firstly reported a stature estimation process using semi-automatic bone measurement software equipped with artificial intelligence. Multiple measurements of femurs of adult Japanese cadavers were performed using automatic three-dimensional reconstructed CT images of femurs. After manually setting four points on the femur, an automatic measurement was acquired. The relationships between stature and five femoral measurements, with acceptable intraobserver and interobserver errors, were analyzed with single regression analysis using the standard error of the estimate (SEE) and the coefficient of determination (R2). The maximum length of the femur (MLF) provided the lowest SEE and the highest R2; the SEE and R2 in all cadavers, males and females, respectively, were 3.913 cm (R2 = 0.842), 3.664 cm (R2 = 0.705), and 3.456 cm (R2 = 0.686) for MLF on the right femur, and 3.837 cm (R2 = 0.848), 3.667 cm (R2 = 0.705), and 3.384 cm (R2 = 0.699) for MLF on the left femur. These results were non-inferior to those of previous reports regarding stature estimation using the MLF. Stature estimation with this simple and time-saving method would be useful in forensic medical practice.

Impact of the COVID-19 pandemic on pathological autopsy practices in Japan.

During the coronavirus disease 2019 (COVID-19) pandemic, autopsies have provided valuable insights into the pathogenesis of COVID-19. The precise effect of this pandemic on autopsy procedures in Japan, especially in instances unrelated to COVID-19, has not yet been established. Therefore, we conducted a questionnaire survey from December 2020 to January 2021 regarding the status of pathological autopsy practices in Japan during the first year of the COVID-19 pandemic. The questionnaire was sent to 678 medical facilities with pathologists, of which 227 responded. In cases where a confirmed diagnosis of COVID-19 was not made at the time of autopsy, many facilities counted them as suspected COVID-19 cases if pneumonia was suspected clinically. At around half of the sites, autopsies were prohibited for suspected COVID-19 cases. In addition, the number of autopsies of non-COVID-19 cases during the pandemic period was also investigated, and a significant decrease was observed compared with the incidence in the pre-pandemic period. The COVID-19 pandemic has affected not only the autopsies of COVID-19 cases but also the entire practice of pathological autopsies. It is necessary to establish a system that supports the implementation of pathological autopsy practices during the pandemic of an emerging infectious disease.

Biomarker profiling of postmortem blood for diabetes mellitus and discussion of possible applications of metabolomics for forensic casework.

Acute metabolic disorders of diabetes mellitus (DM), such as diabetic ketoacidosis, hyperosmolar hyperglycemic state, and hypoglycemia, are life-threatening and difficult to diagnose postmortem owing to lack of macroscopic and microscopic findings, especially when the medical history of the patient is not available before autopsy. Although various biochemical tests, including ketone bodies and hemoglobin A1c, have been used to diagnose diabetes in the postmortem setting, each marker has some limitations. Consequently, it would be helpful in forensic practice to find new biomarkers reflecting the decedent's history of DM irrespective of whether the DM was being treated. Metabolomics enables the non-targeting analysis of biomarkers, and metabolomics was performed on postmortem blood from decedents with and without a DM history to determine whether a marker reflecting DM could be identified. The statistical analysis, including primary component analysis, presented a potent set of metabolites that could be used for the forensic diagnosis of DM. Qualitative analysis revealed significantly lower sphingomyelin and plasmalogen lipid levels and higher lysophospholipid levels in the DM group. Meanwhile, some discrepancies in the levels of some classes of phospholipids were noted between samples from living and deceased persons. This suggests that further metabolomics using postmortem samples rather than living persons' samples is required to identify markers that can be used for forensic diagnosis.

Age estimation by evaluation of osteophytes in thoracic and lumbar vertebrae using postmortem CT images in a modern Japanese population.

Estimation of age at death is important in forensic investigations of unknown remains. There have been several reports on applying the degree of osteophyte formation-an age-related change in the vertebral body-for age estimation; however, this method is not yet established. This study investigated a method for age estimation of modern Japanese individuals using osteophytes measured on CT images. The sample included 250 cadavers (125 males) aged 20-95 years. The degree of osteophyte formation was evaluated as score O (0-5 points), and the degree of fusion of the osteophytes between the upper and lower vertebrae was evaluated as score B (0-2 points). Age estimation equations were developed using regression analyses with seven variables, determined by scores O and B, and the equation with the smallest standard error of estimate (SEE) was obtained when the number of vertebrae with score O ≥ 2 was used as the explanatory variable. Age estimation with SEE of about 10 years was possible even when partial vertebrae with a high degree of osteophyte formation were used, showing its potential for practical application. The cutoff value for age estimation was established using the receiver operating characteristic curve analysis, wherein good results were obtained for all variables (area under the curve ≥ 0.8). The combination of the estimation equation and the cutoff value can narrow the range of age estimates.

Trends and Characteristics in Health Care-related Deaths Investigated through Medico-legal Autopsies after System Changes in Japan.

In Japan, a new cause-of-death investigation system and related new laws were enacted in the mid-2010s. These laws provided for an autopsy system for non-criminal unnatural deaths and a medical accident investigation system outside the criminal justice process for health care-related deaths. We retrospectively explored changes in the number and characteristics of medico-legal autopsy cases of health care-related deaths in Chiba Prefecture, Japan, and examined trends over time during these reforms. We found that the percentage of forensic autopsies based on the Code of Criminal Procedure for health care-related deaths had decreased significantly. The number of autopsies of accidental and unintentional deaths in nursing homes, which are not covered by the newly established medical accident investigation system, has been increasing, reflecting the ageing of society. The trend toward decriminalisation of health care-related deaths was expected to contribute more to medical safety if the scope was expanded and a system for disclosure of autopsy information was established.

Postmortem magnetic resonance imaging revealed bilateral globi pallidi lesions in a death associated with prolonged carbon monoxide poisoning: a case report.

A man and a woman were found dead in the same car with a burned coal briquette. The cause of death of the woman was assigned to acute carbon monoxide (CO) poisoning without difficulty based on typical findings associated with this condition, including elevation of carboxyhaemoglobin (COHb). However, the man had an unremarkable elevation of COHb and a higher rectal temperature compared to that of the woman. Postmortem computed tomography (PMCT) revealed ambiguous low-density areas in the bilateral globi pallidi. Further analysis by postmortem magnetic resonance (PMMR) imaging showed these lesions more clearly; the lesions appeared as marked high signal intensity areas on both the T2-weighted images and the fluid-attenuated inversion recovery sequences. A subsequent autopsy revealed signs of pneumonia, dehydration, starvation, and hypothermia, suggesting that the man died from prolonged CO poisoning. Both globi pallidi contained grossly ambiguous lesions, and a detailed neuropathologic investigation revealed these lesions to be coagulative necrotic areas; this finding was compatible with a diagnosis of prolonged CO poisoning. This case report shows that postmortem imaging, especially PMMR, is useful for detecting necrotic lesions associated with prolonged CO poisoning. This report further exemplifies the utility of PMMR for detecting brain lesions, which may be difficult to detect by macroscopic analysis.

Extraglottic Airway Device Misplacement: A Novel Classification System and Findings in Postmortem Computed Tomography.

STUDY OBJECTIVE: Extraglottic airway devices are frequently used during cardiac arrest resuscitations and for failed intubation attempts. Recent literature suggests that many extraglottic airway devices are misplaced. The aim of this study is to create a classification system for extraglottic airway device misplacement and describe its frequency in a cohort of decedents who died with an extraglottic airway device in situ. METHODS: We assembled a cohort of all decedents who died with an extraglottic airway device in situ and underwent postmortem computed tomographic (CT) imaging at the state medical examiner's office during a 6-year period, using retrospective data. An expert panel developed a novel extraglottic airway device misplacement classification system. We then applied the schema in reviewing postmortem CT for extraglottic airway device position and potential complications. RESULTS: We identified 341 eligible decedents. The median age was 47.0 years (interquartile range 32 to 59 years). Out-of-hospital personnel placed extraglottic airway devices in 265 patients (77.7%) who subsequently died out of hospital; the remainder died inhospital. The classification system consisted of 6 components: depth, size, rotation, device kinking, mechanical blockage of ventilation opening, and injury. Under the system, extraglottic airway devices were found to be misplaced in 49 cases (14.4%), including 5 (1.5%) that resulted in severe injuries. CONCLUSION: We created a novel extraglottic airway device misplacement classification system. Misplacement occurred in greater than 14% of cases. Severe traumatic complications occurred rarely. Quality improvement activities should include review of extraglottic airway device placement when CT images are available and use the classification system to describe misplacements.

New Mexico's COVID-19 Experience.

ABSTRACT: The 2019 novel coronavirus disease (COVID-19) has spread worldwide, infiltrating, infecting, and devastating communities in all locations of varying demographics. An overwhelming majority of published literature on the pathologic findings associated with COVID-19 is either from living clinical cohorts or from autopsy findings of those who died in a medical care setting, which can confound pure disease pathology. A relatively low initial infection rate paired with a high biosafety level enabled the New Mexico Office of the Medical Investigator to conduct full autopsy examinations on suspected COVID-19-related deaths. Full autopsy examination on the first 20 severe acute respiratory syndrome coronavirus 2-positive decedents revealed that some extent of diffuse alveolar damage in every death due to COVID-19 played some role. The average decedent was middle-aged, male, American Indian, and overweight with comorbidities that included diabetes, ethanolism, and atherosclerotic and/or hypertensive cardiovascular disease. Macroscopic thrombotic events were seen in 35% of cases consisting of pulmonary thromboemboli and coronary artery thrombi. In 2 cases, severe bacterial coinfections were seen in the lungs. Those determined to die with but not of severe acute respiratory syndrome coronavirus 2 infection had unremarkable lung findings.

CT imaging of extraglottic airway device-pictorial review.

Compared to intubation with a cuffed endotracheal tube, extraglottic airway devices (EGDs), such as laryngeal mask airways, are considered less definitive ventilation conduit devices and are therefore often exchanged via endotracheal intubation (ETI) prior to obtaining CT images. With more widespread use and growing comfort among providers, reports have now described use of EGDs for up to 24 h including cases for which clinicians obtained CT scans with an EGD in situ. The term EGD encompasses a wide variety of devices with more complex structure and CT appearance compared to ETI. All EGDs are typically placed without direct visualization and require less training and time for insertion compared to ETI. While blind insertion generally results in functional positioning, numerous studies have reported misplacements of EGDs identified by CT in the emergency department or post-mortem. A CT-based classification system has recently been suggested to categorize these misplacements in six dimensions: depth, size, rotation, device kinking, mechanical blockage of the ventilation opening(s), and injury from EGD placement. Identifying the type of EGD and its correct placement is critically important both to provide prompt feedback to clinicians and prevent inappropriate medicolegal problems. In this review, we introduce the main types of EGDs, demonstrate their appearance on CT images, and describe examples of misplacements.

Sudden death due to tension pneumothorax associated with pulmonary tuberculosis.

A man in his seventies who lived alone was found dead in his home. Postmortem computed tomography (CT) performed prior to autopsy showed right-sided tension pneumothorax. Autopsy revealed an active pulmonary tuberculosis (TB) lesion. Macroscopic and histopathological findings showed pleural infiltration by TB lesions, suggesting that tension pneumothorax developed in association with TB infection. Routine postmortem CT performed prior to autopsy is useful in screening for TB because the presence of TB lesions can be confirmed from characteristic pulmonary findings. However, it may be difficult to identify tuberculous pulmonary lesions on CT if pneumothorax occurs and the lung collapses completely as in this case. Thus, forensic pathologists and radiologists should be cognizant of this rare complication of TB.

Postmortem CT and MRI findings of massive fat embolism.

OBJECTIVE: To elucidate postmortem computed tomography (PMCT) and postmortem magnetic resonance (PMMR) imaging findings suggesting massive fat embolism. MATERIALS AND METHODS: Consecutive forensic cases with PMCT and PMMR scans of subjects prior to autopsy were assessed. For PMCT, 16- or 64-row multidetector CT scans were used; for PMMR, a 1.5 T system was used. MRI sequences of the chest area included T2- and T1-weighted fast spin-echo imaging, T2*-weighted imaging, T1-weighted 3-dimensional gradient-echo imaging with or without a fat-suppression pulse, short tau inversion recovery, and in-phase/opposed-phase imaging. At autopsy, forensic pathologists checked for pulmonary fat embolism with fat staining; Falzi's grading system was used for classification. RESULTS: Of 31 subjects, four were excluded because fat staining for histopathological examination of the lung tissue could not be performed. In three of the remaining 27 subjects, histology revealed massive fat embolism (Falzi grade III) and the cause of death was considered to be associated with fat embolism. CT detected a "fat-fluid level" in the right heart or intraluminal fat in the pulmonary arterial branches in two subjects. MRI detected these findings more clearly in both subjects. In one subject, CT and MRI were both negative. There were no positive findings in the 24 subjects that were fat embolism-negative by histology. DISCUSSION AND CONCLUSION: In some subjects, a massive fat embolism can be suggested by postmortem imaging with a "fat-fluid level" in the right heart or intraluminal fat in the pulmonary arterial branches. PMMR potentially suggests fat embolism more clearly than PMCT.

Fatal hemorrhage complicated with methamphetamine poisoning and its post-mortem CT features.

The purpose of this study was to assess the incidence of fatal hemorrhage complicated with methamphetamine (MA) poisoning and to examine the postmortem computed tomography (PMCT) features of fatal intracerebral hemorrhage (ICH) with and without MA poisoning. The study also attempted to determine the differences in PMCT between those two groups. Consecutive medicolegal autopsy data from November 2011 to February 2018 were searched for 3044 cases. First, the incidence and distribution of all cases of nontraumatic fatal hemorrhage with various causes were examined. Second, cases of ICH on the basal ganglia and brain stem were extracted. The PMCT findings were compared with respect to nine parameters: volume of hematoma, ventricular perforation, midline shift distance, aortic calcification, calcification of aortic valve, calcification of coronary artery, cardiothoracic ratio, circumference of ascending aorta, and volume of bladder contents. Of the 3044 cases, 97 were nontraumatic fatal hemorrhage; of these 97 cases, 20 were classified as MA poisoning with 9 ICH cases, and 60 cases were classified as non-MA poisoning with 14 ICH cases. A statistically significant difference in ages was observed between the two groups. On PMCT comparison of ICH, statistically significant differences were evident in the midline shift distance and calcification of the aortic valve. Forensic radiologists should be aware of the possibility of ICH with MA poisoning if fatal hemorrhage is detected on PMCT. Younger age, less calcification of the aortic valve, and a remarkable midline shift may be the keys to recognition.

Utility of contrast-enhanced computed tomography in forensic examination of a stab wound in living individuals.

In cases of inflicted injury, the process of examining the patient for external injuries and documenting the findings is important for forensic assessment, including estimating or determining the type of weapon used and the circumstances of the violence. However, external examination is obviously limited in assessing internal injury. Here, we report the cases of two patients who survived stab wounds, where the findings of contrast-enhanced computed tomography (CT) performed for clinical diagnosis in the hospital were useful for forensic injury evaluation. In both cases, contrast-enhanced CT clearly displayed the injuries to the parenchymal organs and enabled the estimation of the direction and depth of the stab wounds by depicting the track and base of the wounds on acquired images. With the addition of the findings from examination of the external wound, the stab wounds in both victims were consistent with injury caused by the suspected weapon. Recently, imaging modalities including CT have become useful supplemental tools for precise forensic evaluation. Imaging findings obtained from these modalities could especially provide useful information for forensic assessment in clinical forensic medicine because examination of internal injury in the living body cannot generally be performed. Research on the precise diagnostic value of this method is required to utilize this method adequately in clinical forensic medicine.

Postmortem angiography revealing traumatic rupture of the intracranial internal carotid artery.

Diagnosis of traumatic subarachnoid hemorrhage (SAH), although relatively rare, is important in forensic medicine. It is mostly associated with rupture of the vertebrobasilar artery. Traumatic aneurysm of the intracranial part of the internal carotid artery (ICA) is also rare but has been reported in several studies. It is thought that the intracranial ICA is injured by blunt force to the head, neck, and chest. However, traumatic SAH with fatal acute course resulting from rupture of the ICA is especially uncommon: only two fatal cases without an associated aneurysm have been reported in the English-language literature. Although detecting the arterial lesion is required to make a precise diagnosis, this is sometimes impossible by macroscopic examination at autopsy or by investigation after formalin-fixation according to the position of the lesion. We report a rare case of fatal traumatic SAH associated with intracranial ICA rupture. Postmortem computed tomography angiography was useful to confirm the lesion.

Determination of sex on the basis of hyoid bone measurements in a Japanese population using multidetector computed tomography.

Sex determination for unidentified human remains is important because the determined sex is usually used as a foundation for the estimation of other biological profiles. This study investigated the sexual dimorphism of the adult hyoid bone and developed discriminant equations to accurately estimate sex in a contemporary Japanese population using measurements on two-dimensional computed tomography (CT) images. The study sample comprised 280 cadavers (140 males, 140 females) of known age and sex that underwent postmortem CT and subsequent forensic autopsy. In accordance with previous studies, seven measurements were performed using two-dimensional CT reconstructed images. Most measurements of males were significantly greater than those of females. The perpendicular length from the most anterior edge of the hyoid body to the line that connects the most distal points of the greater horns of the hyoid and the linear distance between the most lateral edges of the hyoid body most significantly contributed to sex determination. This study demonstrated that discriminant functions on the basis of three measurements provided higher rates of accurate sex classification (93.3-94.6%) than univariate functions. Therefore, the hyoid bone is highly sexually dimorphic in the contemporary Japanese population and may be useful in forensic contexts for sex determination with a high level of accuracy.