星岡 佑美

In this study, we assessed the sexual dimorphism of the contemporary Japanese skull and established sex discriminant function equations based on cranial measurements using three-dimensional (3D) computed tomography (CT) images. The CT images of 263 corpses (142 males, 121 females) that underwent postmortem CT scanning and subsequent forensic autopsy were evaluated. Twenty-one cranial measurements were obtained from 3D CT reconstructed images, which extracted only bone data. We performed descriptive statistics and discriminant function analyses for the measurements. Nineteen measurements were significantly larger in males, suggesting sexual dimorphism of the Japanese skulls. Univariate discriminant function analyses using these measurements showed a sex classification accuracy of 57.8-88.2%, and bizygomatic breadth provided the highest correct prediction rate. Multivariate discriminant function analyses offered the most accurate model using seven variables with an estimation rate of 93.9%. Our results suggest that cranial measurements based on 3D CT images may help in the sex estimation of unidentified bodies in a contemporary Japanese population.

The mechanical properties and thickness of adult temporal and occipital bones were examined in modern Japanese forensic samples. Cranial bones were obtained from 293 Japanese corpses (179 men and 114 women). During autopsy, left temporal (LT), right temporal (RT), and occipital (O) bone samples were extracted from each skull. Sample thickness (ST) was measured using multidetector computed tomographic imaging. The fracture load (FL) of each sample was measured by a bending test, in which the flexural strength (FS) was calculated. The FL and ST values for O were significantly greater compared with those of the LT and RT bones. The temporal bones were thinner compared with other parts of the skull and at greater risk for fracture. There is a need to take precautions to prevent temporal bone fractures. There were no significant differences in any of the values between LT and RT, indicating bilateral symmetry of the temporal bones. There were significant negative correlations between age and the FL and FS values for all sites in both sexes, except for O in the male samples, suggesting that older individuals are at increased risk for fractures. No significant correlations were observed between age and ST values in any of the samples. There were significantly positive correlations between FL and ST values at all sites regardless of sex.

In forensic medicine, hypothermia is a frequently encountered cause of death, and this characteristic provides public health information to prevent similar deaths in the future. Previous studies revealed regional differences in hypothermia occurrence (indoors or outdoors). However, to our knowledge, no recent studies in Japan have directly compared the characteristics of indoor- and outdoor-onset cases based on forensic autopsy reports. Hence, this study aimed to determine the characteristics and risks of unexpected hypothermia-related death. It included 218 cases from the Chiba Prefecture, Japan, wherein forensic autopsies were performed and hypothermia was diagnosed; these cases were categorized into indoor- and outdoor-onset cases, and their characteristics were examined. The results showed no significant differences between the two groups in relation to the age of onset or residential environment (i.e., the presence or absence of cohabitants). The outdoor-onset group tended to have a higher incidence of dementia. Regarding the causes of hypothermia, the indoor group had more internal causes (p < 0.0001), whereas the outdoor group had more primary and external causes (p < 0.0001 and p = 0.0029, respectively). The indoor group was more undressed than the outdoor group. Atypical antipsychotic components were predominantly detected in the blood in the outdoor group (p = 0.0077). The body mass index tended to be lower in the indoor group than in the outdoor group. Broadening public awareness of the present study findings may aid in developing preventative strategies for hypothermia based on the location of onset.

PURPOSE: The image contrast of postmortem magnetic resonance imaging (MRI) may differ from that of antemortem MRI because of circulator arrest, changes in postmortem tissue, and low-body-temperature scanning conditions. In fact, we have found that the signal intensity of white matter (WM) on T1-weighted spin-echo (T1WSE) images of the postmortem brain was lower than that of gray matter (GM), which resulted in image contrast reversal between GM and WM relative to the living brain. However, the reason for this phenomenon is unclear. Therefore, the aim of this study is to clarify the reason why image contrast reversal occurs between GM and WM of the postmortem brain. MATERIALS AND METHODS: Twenty-three corpses were included in the study (mean age, 60.6 years; range: 19-60 years; mean rectal temperature at scan, 6.9℃; range: 4-11℃). On a 1.5 T MRI system, postmortem T1W-SE MRI of the brain was conducted in the 23 corpses prior to medico-legal autopsy. Next, T1 and T2 of the GM and WM at the level of the basal ganglia were determined in the same participants using inversion recovery and multiple SE sequences, respectively. The proton density (PD) was also calculated from the T1 and T2 images (in the same slice). RESULTS: T1W-SE image contrast between the GM and WM of all postmortem brains was inverted relative to the living brain. T1 (579 ms in GM and 307 ms in WM) and PD (64 in GM and 44 in WM) of the postmortem brain decreased compared with the living brain. While T1 of WM/GM remained below 1 even postmortem, the PD of WM/GM decreased. T2 (110 ms in GM and 98 ms in WM) of the postmortem brain did not differ from the living brain. CONCLUSION: The decrease in PD of WM/GM in the postmortem brain may be the major driver of contrast reversal between the GM and WM relative to the living brain.

The source of diatoms detected in non-drowned bodies have been attributed to postmortem invasion, contamination during autopsy or diatom testing, or "natural load." However, sand aspiration has not been reported as a source. Herein, we report an autopsy case in which diatoms were detected in a non-drowned human who had aspirated mud. A man in his 60 s was found dead at a harbor park in Japan. His whole body was covered with sand, including his face. A situational investigation suggested that he may have entered the sea. Autopsy revealed intratracheal mud, with no obvious findings indicating drowning, suggesting that he died from mud aspiration probably due to hypothermia or non-lethal ethanol intoxication. In the diatom test, 10-100 diatoms/g were detected in bilateral lung samples, which were similar to those found in the intraoral and intratracheal mud and the sand samples from around the discovery site and not similar to those found in the seawater samples. The diatoms in the stomach content exhibited an intermediate trend between those found in the sand and seawater. Therefore, careful qualitative and quantitative analyses are required to differentiate between true drowning and false-positives in non-drowning cases to determine the cause of death.

BACKGROUND: Radiocarbon (14C), whose levels increased in the atmosphere between 1955 and 1963, accumulates in the enamel of human teeth only during the process of tooth formation and has been applied to estimate the birth year of unidentified corpses. However, enamel isolation from teeth is time-consuming and labor-intensive. Therefore, this study aimed to estimate the birth year using 14C in the crown of a single mandibular first premolar tooth. MATERIALS AND METHODS: Fourteen mandibular first premolars collected from forensic autopsies were analyzed. For nine teeth, each tooth was cut longitudinally: half of the tooth was enamel, and the other half was crown (1). For the other five teeth, the entire crown was used (2). Thereafter, the 14C concentration in each tooth was measured using accelerator mass spectrometry. RESULTS: The absolute error between the actual date of birth (DOB) and the estimated DOB was within the range of 1.0-8.8 years in the enamel of five teeth and 0.1-4.0 years in the crown halves of seven teeth (1). For the five teeth with entire crowns, the absolute errors ranged between 0.3 and 3.0 years (2). CONCLUSION: The absolute error of 14C-based year of birth estimation using the powdered crown of the mandibular first premolar teeth ranged between 0.1 and 4.0 years. Our method, which involves pulverizing an entire crown, eliminates the need for the equipment, time, and labor associated with enamel isolation. Therefore, 14C dating using powdered crowns of mandibular premolars can be useful for birth year estimation.

Abstract Paliperidone is a widely used antipsychotic agent detected in many fatal intoxications and suicide cases. In forensic toxicology, the accurate determination of blood paliperidone concentrations is required to prove death by paliperidone poisoning. However, the lethal concentration of paliperidone in blood at autopsy differs from that at the time of death. In this study, we found that paliperidone was decomposed by hemoglobin (Hb) through the Fenton reaction in a temperature-dependent fashion. The mechanism underlying paliperidone decomposition involves the cleavage of its C–N bond linker moiety. The mass spectra obtained by liquid chromatography–quadrupole orbitrap mass spectrometry revealed the formation of 6-fluoro-3-(4-piperidinyl)benzisoxazole (PM1) in Hb/H2O2 solution incubated with paliperidone, as well as in the blood of individuals who died from intentional ingestion of paliperidone. These results suggest that PM1 is the only metabolite produced from paliperidone as a result of temperature-dependent, postmortem changes induced by Hb via the Fenton reaction and may be useful as a biomarker to correct for the concentration of paliperidone in blood at the time of death in clinical cases.

A male in his late adolescence fell into the sea and was found 50 min later with cardiopulmonary arrest. He was revived approximately 260 min after he drowned. Although he received several treatments, including venoarterial extracorporeal membrane oxygenation and continuous hemodiafiltration, he was clinically diagnosed with brain death. He died 10 days after the accident. The autopsy did not reveal any unremarkable findings other than those associated with post-resuscitation changes and medical treatment. The diatom test revealed 47.9, 311.6, and 577.5 diatom particles per gram from water, left lung, and right lung samples, respectively. No diatoms were detected in a 10 g liver sample, and 1 diatom was detected in each of approximately 12 g of bilateral kidney samples, which was different from the abundant species in the lung samples. The diatom test of the closed organs could be considered false negative for confirming drowning death since diatoms can also be detected in non-drowned cadavers on dry land. This suggests that diatoms might not reach the closed organs via circulation and that the diatom test of closed organ samples might no longer be necessary to confirm drowning deaths.

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.

Forensic entomology (FE) involves the collection and analysis of necrophagous insects and arthropods for postmortem interval estimation based on their growth and succession. In Japan, research on FE is limited, and the predominant species of necrophagous insects and their distribution have not been clarified. The present study aimed to clarify the actual situation of insects, targeting Diptera collected from human cadavers, in Chiba Prefecture. We targeted the cases for which specimens could be collected from forensic autopsies conducted at the Legal Medicine Department of Chiba University Graduate School of Medicine or from human bodies handled by the Chiba Police in 2019. We specifically chose cases from which adult insects could be bred. Fifty cases were applicable, and 47 cases were successful in rearing adult flies. Sixteen species of Diptera were identified: six species of Calliphoridae, four species of Sarcophagidae, and a few species of Fanniidae, Muscidae, Phoridae, Piophilidae, and Stratiomyidae. The most frequently observed species were Lucilia sericata (20 cases) and Chrysomya pinguis (18 cases). For the first time, globally, we recorded the presence of Fannia prisca in a human cadaver. In conclusion, this is the first report to reveal the presence of carrion flies in human death cases in Chiba Prefecture, Japan. Research in FE is important in the context of the Japanese natural and social environment since this can aid forensic investigations conducted by authorities.

OBJECTIVES: To statistically clarify the prevalence and risk factors of infections in forensic autopsy cases in Chiba Prefecture, Japan. The aim was to improve preventive measures against infection in forensic autopsies. METHODS: We retrospectively investigated the positive detection rates of five infections (hepatitis B, HBV; hepatitis C, HCV; human immunodeficiency virus, HIV; human T-lymphotropic virus, HTLV; Treponema pallidum, TP) using 1491 samples obtained in forensic autopsy at our facility from 2014 to 2018. In addition, risk factors related to infection such as methamphetamine and tattoos were analyzed. Pearson's chi-square test was used for statistical analysis, and the difference was judged to be significant at p < 0.05. RESULTS: Among our samples, 9.0% of cadavers tested positive for infection, and the prevalence rates for HBV, HCV, HIV, HTLV, and TP were 1.0%, 6.7%, 0.3%, 0.7%, and 1.1% respectively. Statistically, cadavers linked to information about methamphetamine use had a 7.2 times higher rate of infection, and those with tattoos had a 5.6 times higher rate of infection, with HCV being the predominant cause. CONCLUSIONS: To limit the risk of infection among autopsy workers, cadavers and samples should be handled on the presupposition that the bodies are at risk of infections. It is also important to obtain as much information as possible about the medical history and potential illegal drug use to help assess the risk of infection in a patient during forensic autopsy. We propose that all autopsy cases should be screened for infections whenever possible.

Fat embolism syndrome is a life-threatening condition in which fatty substances enter the circulation and cause respiratory distress and neurological symptoms. It can occur following trauma and severe fat embolism occurring soon after trauma is known as fulminant fat embolism syndrome. Although fat staining of the lungs is helpful for diagnosing fat embolism syndrome at autopsy, clinical and other information is needed to determine the relationship between cause of death and the syndrome. In this report, we describe the macroscopic, microscopic, and computed tomography (CT) findings specific for fat embolism that were observed in a patient with fulminant fat embolism syndrome who died soon after the injury. An 85-year-old woman fell from a bath stretcher during assisted bathing and died 3 h later. Autopsy revealed fractures of the left femoral neck and other bones, as well as large amounts of fat-like material in the right and left pulmonary arteries. Histological examination of the lung with Oil red O staining showed extensive fat vacuoles. Based on these findings and postmortem CT images of the fractures and fatty globules in the pulmonary arteries detected prior to death, the cause of death was determined to be blunt force trauma, with fat embolism syndrome playing a significant role. This case is an example of fulminant fat embolism, which can be fatal in a short period of time, and demonstrates that CT performed postmortem but before autopsy can be useful in detecting fat embolism syndrome due to trauma.

OBJECTIVE: The diagnosis of drowning is an important issue in forensic investigations. Moreover, discriminating between seawater and freshwater drowning is crucial to identify where the drowning occurred. The present study aimed to investigate electrolyte concentrations in pleural fluid in decomposed bodies in late postmortem intervals and derive cut-off values for the diagnosis of seawater and freshwater drowning. STUDY DESIGN: Data were collected from 44 seawater drowning cases, 60 freshwater drowning cases, and 30 non-drowning cases with pleural effusion which served as controls. The levels of sodium ion (Na+), potassium ion (K+), and chloride ion (Cl-) of pleural fluid were measured, and two indices were calculated: summation of Na+ and K+ levels (SUM Na + K), and summation of Na+, K+, and Cl- levels (SUM Na + K + Cl). The means of the three ion concentrations and two indices significantly differed between the three groups (p < 0.0001). RESULTS: The receiver operating characteristic analysis revealed that the sensitivity and specificity were both 1.000 for SUM Na + K + Cl of 288.3 mEq/L between the seawater and control groups. The Na+ value of 109.0 mEq/L also had a high sensitivity of 0.977 and a specificity of 0.933 in the seawater and control groups. The sensitivity and specificity were 0.967 and 1.000, respectively, for SUM Na + K of 123.2 mEq/L between the freshwater and control groups. CONCLUSION: The electrolyte concentrations in pleural effusion may be useful for the diagnosis of drowning in decomposed bodies with a longer postmortem interval.

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.

Rapid and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in dead bodies is essential to prevent infection among those working with dead bodies. This study focused on the Smart Amplification (SmartAmp) method, which has a short examination time (approximately an hour), is simple to perform, and demonstrates high specificity and sensitivity. This method has already been used for clinical specimens; however, its effectiveness in dead bodies has not been reported. This study examined the SmartAmp method using 11 autopsies or postmortem needle biopsies performed from January to May, 2021 (of these, five cases tested positive for SARS-CoV-2 by quantitative real-time polymerase chain reaction (qRT-PCR) and six cases tested negative). Swab samples were collected from the nasopharynx, oropharynx, or anus and the SmartAmp and qRT-PCR results were compared. For the nasopharynx and oropharynx samples, the same results were obtained for both methods in all cases; however, for the anal swabs, there was one case that was positive according to qRT-PCR but negative according to the SmartAmp method. The SmartAmp method may therefore be less sensitive than qRT-PCR and results may differ in specimens with a low viral load, such as anal swabs. However, in the nasopharynx and oropharynx specimens, which are normally used for testing, the results were the same using each method, suggesting that the SmartAmp method is useful in dead bodies. In the future, the SmartAmp method may be applied not only during autopsies, but also in various situations where dead bodies are handled.

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.

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.

Image acquisition of dead bodies, particularly using postmortem computed tomography (PMCT), has become common in forensic investigations worldwide. Meanwhile, in countries such as Japan which have an extremely low rate of autopsy, PMCT is being increasingly used in the clinical field to certify the cause of death (COD) without performing an autopsy or toxicological tests, even in cases of unnatural death. Additionally, these PMCT images are predominantly interpreted by clinical personnel such as emergency physicians or clinicians who are not trained in PMCT interpretation and who work for the police, that is, the so-called police doctors. Many potential pitfalls associated with the use of PMCT have been previously described in textbooks and published papers, including the pitfalls of not performing a complete forensic pathology investigation, and the use of physicians without appropriate PMCT training to interpret PMCT and direct death investigation and certification. We describe five examples in which apparent misdiagnosis of COD based on PMCT misinterpretation was revealed by autopsy. Here are the five examples of errors: (1) Postmortem changes were misinterpreted as COD, (2) resuscitation effects were misinterpreted as COD, (3) COD was determined after an incomplete examination, (4) fatal findings caused by external origin were wrongly interpreted as 'of internal origin' based on PMCT, and (5) non-fatal findings on PMCT were wrongly interpreted as fatal. Interpretation of PMCT by appropriately trained physicians and an accompanying complete forensic investigation, including autopsy when indicated, is necessary to prevent significant errors in COD determination and related potential adverse medicolegal consequences.

Streptococcal toxic shock syndrome (STSS) is a severe infection most commonly caused by group A streptococcus. It is clinically characterized by rapidly progressive multiple organ failure and septic shock. This report presents four fatal cases associated with STSS. In two cases (cases 2 and 3), the portals of entry may be ulcer and mucosa at the surgical site; the initial symptoms in these cases included fever. In the other cases, the portal of entry was unknown; the initial symptom was pain. In two cases (cases 1 and 3), malpractice was suspected before autopsy. At autopsy, blood culture was positive for group A streptococcus in all of the present cases. Although C-reactive protein levels were increased, procalcitonin levels were not markedly elevated. This is the first report of autopsy cases associated with STSS in which postmortem computed tomography was performed; the swelling of muscles and increased concentrations of peripheral subcutaneous tissue without gas may be characteristic findings. Histology revealed extensive bacterial colonies and necrosis with mild neutrophilic reaction in two cases (cases 3 and 4), and hemophagocytosis in two cases (cases 1 and 4). It is essential to perform appropriate examinations and make a proper diagnosis because STSS still has a high fatality rate and medical malpractice is often suspected. In addition, it is important to evaluate STSS again for the reduction of the fatal cases associated with STSS.

Hypochlorous acid, produced by myeloperoxidase upon neutrophil activation, can oxidize various compounds and exert antimicrobial activity in vivo. To elucidate the mechanisms underlying the reactions of the unsaturated phosphatidylcholines, which abound in cell membranes, with hypochlorous acid, we identified and examined phosphatidylcholine chlorination and oxidation products formed under various reaction conditions. We first investigated the products of unsaturated phosphatidylcholine and hypochlorous acid reaction with respect to hypochlorite concentration and reaction time. Next, we examined the lipids extracted postmortem from human abscesses. For all the analyses, we used liquid chromatography-quadrupole time-of-flight mass spectrometry. Various compounds, including phosphatidylcholine chlorohydrin and phosphatidylcholine hydroxide/epoxide, were detected. Oxidized phosphatidylcholines were mainly detectable upon reaction with low concentrations of sodium hypochlorite, whereas chlorinated phosphatidylcholines formed in the presence of higher concentrations. In human abscesses, oxidized phosphatidylcholines were detected in the cases with high procalcitonin concentration, whereas chlorinated phosphatidylcholines were undetected. The detections of oxidized phosphatidylcholines in human tissues might indicate previous exposure to hypochlorous acid in septic cases. Our results provide insight into the mechanisms underlying pathogen survival following inflammation associated with neutrophil activation and topical myeloperoxidase release and show postmortem biomarkers candidates for sepsis.

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.

Only a few reports have described radiological findings of parasite depicted by postmortem computed tomography (PMCT). We herein present a case in which the PMCT of a 29-year-old man revealed Taenia saginata, a species of tapeworms, inside the intestine. The image of the parasite appeared as a low-density linear or cystic pattern of gas bubbles located within the lumen of the small bowel. We named this finding as 'PseudoPneumatosis intestinalis' sign, since which mimicked the findings of Pneumatosis intestinalis in a clinical setting. In this report, we present the image and discuss the importance of the findings of parasites on PMCT performed before autopsy.

Age estimation of cadavers from post-mortem "chest plate" using conventional radiography, which involves radiographic assessment of ossification around the sternum and rib ends, has been evaluated without fruitful results. This study examined the value of images of the chest plate obtained by three-dimensional post-mortem CT for estimation of age at time of death in a Japanese population. Five chest plate ossification scores were evaluated in 320 subjects, including ossification of the first costal cartilage (OF), ossification of the second to seventh costal cartilages at the rib (OR) and sternal (OS) ends, fusion of the manubriosternal joint (FM), and fusion of the xiphisternal joint (FX). OS was found to have the highest correlation with age while FM had no significant correlation. The best composite score for age estimation was the summative score for both sides of the OS and the right side of the OF and FX, for which the coefficient of determination (R2) and the standard error of estimation (SEE) were 0.608 and 12.44 years, respectively, for men and 0.590 and 14.65 years for women. The accuracy of the model was tested in a further 26 male and 24 female subjects, and the accuracy rate within the first SEE was 57.69% and 70.83%, respectively. This rapid and non-invasive method of age estimation in the chest plate area is superior to conventional methods and could be useful for estimation of age at time of death in the Japanese population.

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.

To estimate forensic age, the Study Group of Forensic Age Diagnostics of the German Association of Forensic Medicine (AGFAD) has recommended the radiological investigation of the medial clavicular epiphysis (MCE). This study aimed to investigate the relation between the maturation of the MCE and age in a contemporary Japanese population using a standard five-stage system by Schmeling et al. and Kellinghaus substage system. A total of 207 cadavers (128 males, 79 females) of known age and sex that underwent postmortem computed tomography (CT) and subsequent forensic autopsy were obtained. The earliest appearance for stage 3c was 18.1 years in the male subjects and 18.4 years in the female subjects. Our results were consistent with those in previous studies and indicate that stage 3c is crucial for medico-legal processes in evaluating age in various countries. Similar studies on the staging of the MCE using CT images in other populations, particularly in Asians, are required.

In forensic investigations, it is important to detect traumatic axonal injuries (TAIs) to reveal head trauma that might otherwise remain occult. These lesions are subtle and frequently ambiguous on macroscopic evaluations. We present a case of TAI revealed by pre-autopsy postmortem magnetic resonance imaging (PMMR). A man in his sixties was rendered unconscious in a motor vehicle accident. CT scans revealed traumatic mild subarachnoid hemorrhage. Two weeks after the accident he regained consciousness, but displayed an altered mental state. Seven weeks after the accident, he suddenly died in hospital. Postmortem computed tomography (PMCT) and PMMR were followed by a forensic autopsy. PMMR showed low-intensity lesions in parasagittal white matter, deep white matter, and corpus callosum on three-dimensional gradient-echo T1-weighted imaging (3D-GRE T1WI). In some of these lesions, T2∗-weighted imaging also showed low-intensity foci suggesting hemorrhagic axonal injury. The lesions were difficult to find on PMCT and macroscopic evaluation, but were visible on antemortem MRI and confirmed as TAIs on histopathology. From this case, it can be said that PMMR can detect subtle TAIs missed by PMCT and macroscopic evaluation. Hence, pre-autopsy PMMR scanning could be useful for identifying TAIs during forensic investigations.

We aimed to reproduce the anthropometrical measurements of femoral dimensions using multi-planar reconstruction (MPR) computed tomography (CT); to assess the feasibility of sex estimation using femoral measurements through this approach, and to establish the corresponding sex estimation thresholds in the modern Japanese population. We used data on 224 cadavers (116 male and 108 female) that were subjected to postmortem CT and subsequent forensic autopsy at our department between October 2009 and July 2016. Four femoral measurements were obtained. Receiver operating characteristic (ROC) curve analysis was performed to test the overall ability of the variables in sex estimation, while the accuracy of the sex estimation was measured by the area under the ROC curve (AUC). The femoral bicondylar breadth showed the largest AUC values (left; 0.973, right; 0.974), followed by the maximum head diameter (left; 0.951, right; 0.955), and maximum femoral length (left; 0.885, right; 0.887). To the best of our knowledge, this is the first report to assess sex estimation based on femoral measurements, using MPR CT images.

We aimed to reproduce the anthropometrical measurement of femoral dimensions using multi-planar reconstruction computed tomography (CT), assess the correlation between stature and femoral measurements obtained by this approach, and establish a regression equation for estimating stature in the modern Japanese population. We used data regarding 224 cadavers (116 males, 108 females) that were subjected to postmortem CT and subsequent forensic autopsy at our department between October 2009 and July 2016. To simulate the placement of the femur on the osteometric board using reconstructed CT images, we defined a virtual horizontal plane (VHP) based on the three most dorsal points of the femur (lateral condyle, medial condyle, and greater trochanter). Five femoral measurements including the maximum femoral length (MFL) were obtained. The correlations between stature and each femoral measurement were expressed in terms of the coefficient of determination (R2). On regression analysis, MFL provided the lowest value for the standard error of the estimation (SEE); the SEE values in all subjects, males, and females, respectively, were 3.783 cm (R2 = 0.832), 3.850 cm (R2 = 0.653), and 3.340 cm (R2 = 0.760) for MFL on the left side and 3.747 cm (R2 = 0.835), 3.847 cm (R2 = 0.650), and 3.290 cm (R2 = 0.687) for MFL on the right side. Multiple regression equations using MFL and femoral epicondylar breadth were slightly superior to simple regression equations in males and in all subjects (SEE = 3.44-3.55 cm), whereas no effective equation could be obtained in females. To our knowledge, this is the first multiple regression equation for stature estimation using only femoral measurements.

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.

Accurate sex estimation from unknown human remains is crucial as an integral and foremost step toward individual identification. The aims of this study were to assess sexual dimorphism of the clavicle and develop discriminant equations for sex estimation in a modern adult Japanese population based on clavicular measurements using three-dimensional (3D) computed tomographic (CT) images. A total of 300 cadavers (150 males, 150 females) of known age and sex that underwent postmortem CT and subsequent forensic autopsy were obtained. Four measurements were performed using 3D CT reconstructed images that extracted only bones based on the CT values, as follows: the linear distances between the medial superior margins of the left and right sternal facets to the lateral points of the left and right acromial ends, and the linear distances between the medial superior margins of the left and right sternal facets to the tips of the left and right conoid tubercles. The mean values of all measurements were significantly greater for male subjects than female subjects. Univariate discriminant function analysis (DFA) provided correct sex prediction rates of 88.3-92.2%. Stepwise DFA for the left and right clavicles yielded sex classification accuracy rates of 92.2% and 91.0%, respectively. In conclusion, clavicular measurements using 3D CT images of a contemporary Japanese population may be useful for sex estimation in forensic contexts.

Analysis of ions in sphenoidal fluid can be a useful index for the diagnosis of drowning. We evaluated the reference ranges of non-drowning cases using statistical methods and three indices: sodium ion (Na+), summation of sodium and potassium ions (SUMNa+K), and summation of sodium, potassium and chloride ions (SUMNa+K+Cl). The reference ranges were 96≤Na+<152, 139≤SUMNa+K<179, 243≤SUMNa+K+Cl<311(mEq/L), respectively. Victim indices outside of the reference ranges indicate that the victim probably inspired water with higher or lower ion concentrations than those of body fluid in sphenoidal sinuses. Compared to the SUMNa+K+Cl index, the Na+ and SUMNa+K indices could distinguish among seawater drowning, freshwater drowning, and non-drowning. In drowning cases, sphenoidal fluid volume and time since death were not correlated, which suggests that water does not enter the sphenoidal sinuses after death and there is a different process for water accumulation in drowning and non-drowning cases. In bathtub cases, this method was not valid for the estimation of inspired water. Although it is necessary to observe the classical signs of drowning, this method is suitable for the estimation of drowning, especially in cases where pleural fluid or diatom tests are not available.

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.

Aim To determine the frequency of cardiopulmonary resuscitation (CPR)-related injuries and factors involved in their occurrence, data based on forensic autopsy and postmortem computed tomography (PMCT) during implementation of the 2010 American Heart Association Guidelines for CPR were studied. Methods We retrospectively evaluated data on adult patients with non-traumatic deaths who had undergone manual CPR and autopsy from January 2012 to December 2014. CPR-related injuries were analyzed on autopsy records and PMCT images and compared with results of previous studies. Results In total, 180 consecutive cases were analyzed. Rib fractures and sternal fractures were most frequent (overall frequency, 66.1 and 52.8%, respectively), followed by heart injuries (12.8%) and abdominal visceral injuries (2.2%). Urgently life-threatening injuries were rare (2.8%). Older age was an independent risk factor for rib fracture [adjusted odds ratio (AOR), 1.06; 95% confidence interval (CI), 1.04-1.08; p &lt; 0.001], &gt;= 3 rib fractures (AOR, 1.06; 95% CI, 1.02-1.09; p = 0.002), and sternal fracture (AOR, 1.03; 95% CI, 1.01-1.05; p &lt; 0.001). Female sex was significantly associated with sternal fracture (AOR, 2.08; 95% CI, 1.02-4.25; p = 0.04). Chest compression only by laypersons was inversely associated with rib and sternal fractures. Body mass index and in-hospital cardiac arrest were not significantly associated with any complications. The frequency of thoracic skeletal injuries was similar to that in recent autopsy-based studies. Conclusions Implementation of the 2010 Guidelines had little impact on the frequency of CPR-related thoracic skeletal injuries or urgently life-threatening complications. Older age was the only independent factor related to thoracic skeletal injuries.

The crush syndrome, in which rhabdomyolysis and trauma occur as a result of heat stroke and drug intoxication, can lead to myoglobinemia. This condition can be diagnosed by measuring myoglobin (Mb) levels in blood and urine. However, postmortem Mb levels are unreliable indicators, since blood Mb concentration drastically increases within a very short time after death and urine cannot always be obtained at dissection; this makes it difficult to diagnose myoglobinemia in a corpse. To address this issue, in this study, we used a lipidomics approach to identify markers that can be used to detect myoglobinemia in postmortem blood samples. We found that increases in levels of fatty acid oxides such as stearic, oleic, linoleic, and arachidonic acid and decreases in levels of plasmalogens and phosphatidylethanolamine in the blood were associated with high Mb level. These results demonstrate that postmortem samples are amenable to lipidomics analysis and provide a set of markers other than Mb that can be used for postmortem diagnosis of myoglobinemia.

The aims of this study was to assess the correlation between stature and clavicular measurements in a contemporary Japanese population using three-dimensional (3D) computed tomographic (CT) images, and to establish regression equations for predicting stature. A total of 249 cadavers (131 males, 118 females) underwent postmortem CT scanning and subsequent forensic autopsy between October 2011 and May 2016 in our department. Four clavicular variables (linear distances between the superior margins of the left and right sternal facets to the anterior points of the left and right acromial ends and between the superior margins of the left and right sternal facets to the left and right conoid tubercles) were measured using 3D CT reconstructed images that extracted only bone data. The correlations between stature and each of the clavicular measurements were assessed with Pearson product-moment correlation coefficients. These clavicular measurements correlated significantly with stature in both sexes. The lowest standard error of estimation value in all, male, and female subjects was 3.62 cm (r(2) = 0.836), 3.55 cm (r(2) = 0.566), and 3.43 cm (r(2) = 0.663), respectively. In conclusion, clavicular measurements obtained from 3D CT images may be useful for stature estimation of Japanese individuals, particularly in cases where better predictors, such as long bones, are not available. (C) 2017 Elsevier B. V. All rights reserved.

Sex determination is an integral and foremost step in determining the identity of an unknown individual. The present study aimed to examine skeletal sexual dimorphism of the sacrum and coccyx using computed tomography (CT) images in a contemporary Japanese population and to derive discriminant function formulae for sex determination. Data were collected from 230 cadavers (115 male and 115 female subjects) subjected to postmortem CT scanning and subsequent forensic autopsy. Seven measurements of the sacrum and coccyx were obtained from CT images of each subject. The measurements were analyzed using descriptive statistics and discriminant function analyses. All except one measurement exhibited statistically significant sexual dimorphism, and the maximum sex determination rate was 83.5% according to discriminant function analyses. The results of this study suggest that discriminant analysis of sacral and coccygeal traits may be useful for the sex determination of skeletal remains in the Japanese population when applied with additional methods, such as morphological trait evaluation of other available bones.

Rhabdomyolysis is characterised by acute kidney injury (AKI) resulting from skeletal muscle injury. Lipid peroxidation-mediated oxidant injury and pro-inflammatory cytokine-mediated inflammatory response play critical roles in the pathogenesis of rhabdomyolysis-induced AKI. The present study aimed to investigate the short-term effects of both lipid peroxidation and inflammatory responses on rhabdomyolysis-induced AKI in a rat model of glycerol-induced rhabdomyolysis. Rhabdomyolysis was induced by the intramuscular injection of 50% glycerol in saline (10 mL/kg) into the hind limbs of rats. Rats were killed 1 or 3 hours after glycerol injection. Time-dependent increases in serum biochemical parameters, including blood urea nitrogen, creatinine, lactate dehydrogenase and creatine phosphokinase levels, were observed 1 hour after glycerol injection. In kidneys, glycerol injection resulted in histopathological changes such as renal tubular injury and renal tubular myoglobin deposition. Levels of N epsilon-(hexanoyl)lysine-modified, 4-hydroxy-2-nonenal-modified, and nitrotyrosine-modified proteins in rat kidneys were unaltered at 1 hour after glycerol injection, but increased significantly at 3 hours. Increases in renal nitric oxide production and the expression levels of inducible nitric oxide synthase, interleukin-6 and tumour necrosis factor-a in the renal parenchyma were observed at 1 hour after glycerol injection and plateaued at 3 hours. Our findings suggest that the pro-inflammatory cytokine-mediated inflammatory response may cause rhabdomyolysis-induced AKI very shortly after glycerol injection, and lipid peroxidation-mediated oxidant injury may promote the development of these pathophysiological processes.

Purpose: The purpose of this study was to determine the incidence of three-rooted mandibular first molars in a contemporary Japanese population using multidetector computed tomography (MDCT) and examine whether this characteristic root form may be useful for identification purposes. Methods: Prior to their forensic autopsies, we obtained MDCT scans of 365 cadavers (255 males, 110 females) with mandibular first molars on both sides. Altogether, 730 mandibular first molars were examined morphologically on reconstructed CT images, and the incidence of three-rooted molars was recorded. The results were analyzed statistically to determine sex and left-right differences using the chi-square test. Results: In all, 189 (25.9%) of the 730 mandibular first molars had three roots: 79 (31.0%) in the 255 males and 35 (31.8%) in the 110 females. No statistically significant difference was found between the sexes. In the 39 individuals who had unilateral three-rooted mandibular first molars, 7 (17.9%) were on the left side and 32 (82.1%) were on the right side, indicating a statistically significant predominance on the right side. Conclusions: The incidence of three-rooted mandibular first molars in contemporary Japanese individuals was 25.9%, with no statistically significant sex difference, but in the case of unilateral three-rooted teeth, with a statistically significant predominance on the right side. Our study found that Japanese and northeastern Asians have a high incidence of the three-rooted mandibular first molars among individuals of Mongolian origin; this finding may be a useful screening tool for identification of unknown individuals. (C) 2016 Published by Elsevier Ireland Ltd.

Accurate sex estimation is important in forensic investigation to determine the identity of unknown individuals. The aim of this study was to investigate the accuracy of sex assessment based on measurements of the second cervical vertebra (C2) using computed tomographic (CT) images in a Japanese population and to develop discriminant function formulae. The data were collected from 224 Japanese cadavers (112 male subjects, 112 female subjects) on which postmortem CT scanning and subsequent forensic autopsy were performed. Nine CT measurements of the C2 were performed for CT images of each subject. The measurements were assessed using descriptive statistics and discriminant function analyses (DFA). All of the measurements demonstrated significant sexual dimorphism. Multiple DFA with stepwise variable selection resulted in multivariable models; a five-variable model reached an accuracy rate of 92.9%. Our results suggest that metric analysis based on CT images of the C2 can accurately determine the sex from the human skeletal remains in a contemporary Japanese population and may be useful for sex estimation in forensic anthropology. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

Coronary artery injury is a rare complication following blunt chest trauma (BCT), and can be fatal. Here we report findings on postmortem selective coronary angiography of right coronary artery rupture after an assault involving blunt trauma to the chest. A woman in her 60s died after her son stomped on her chest. There were no appreciable signs of injury on external examination, and cause of death could not be determined by postmortem computed tomography (PMCT). Internal findings indicated that an external force had been applied to the anterior chest, as evidenced by subcutaneous hemorrhage and pericardial and cardiac contusions. Postmortem coronary angiography revealed irregularity of the intima and of the fat tissue surrounding the proximal part of the right coronary artery associated with a local filling defect. Histopathological examination suggested coronary rupture with dissection of the tunica media and compression of the lumen cavity. The key points in the present case are that no fatal injuries could be determined on external examination, and the heart and coronary artery injuries were not evident on PMCT. Criminality might be overlooked in such cases, as external investigation at the crime scene would be inadequate and could result in a facile diagnosis of cause of death. This is the first report of coronary artery rupture with dissection that was detected by CT coronary angiography, and provides helpful findings for reaching an appropriate decision both forensically and clinically.