千葉 文子

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.

Age estimation is an essential step in identifying human corpses. Several mandibular landmarks have been highlighted as skeletal sites for age estimation since aging causes morphological changes. Reports suggest that mandibular torus size may be associated with aging; however, thorough investigation has not been performed owing to the difficulty in measuring it. Therefore, this study aimed to determine the association between age and mandibular torus thickness using postmortem computed tomography data from Japanese corpses. This study included 2,792 corpses with mean (standard deviation) age of 58.0 (22.4) years (range, 0-101 years) and 67.6 % males. Further, 2,662 (95.3 %), 14 (0.5 %), 59 (2.1 %), and 57 (2.0 %) corpses were in the permanent, mixed, primary, and predental dentition periods, respectively. Multivariable analysis was performed to quantify the impact of age on mandibular torus thickness, adjusting for sex, height, weight, and occlusal contact status. The model also included an interaction term between age and occlusal status because of the potential effect modification by occlusion. Results of the multivariable regression analysis showed that mandibular torus thickness increased with age (the regression coefficients (95 % confidence interval) were 0.6 (0.2-1.0), 0.7 (0.3-1.0), 1.0 (0.6-1.4), 1.3 (0.9-1.7), 1.3 (0.8-1.8), and 1.1 (0.4-1.7) for age groups 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89 years, respectively), especially in males with occlusal contact. A significant association between mandibular torus thickness and age, modified by occlusal status and sex, was identified. Therefore, data regarding the thickness of the mandibular torus and occlusal status may be useful for age estimation in human corpses.

73歳，男性。腹部大動脈瘤の術前検査として，イオパミドールを用いた冠動脈造影CT検査を実施。検査終了直後にアレルギー症状が発現し，その直後からアドレナリン投与などの蘇生処置を行うも，死亡。解剖の結果，致死的な医原性損傷は認めず。生化学検査にてNT-proBNPが高値を示し，トリプターゼおよび非特異的IgEがアナフィラキシーショックの死後診断の文献的カットオフ値を超えて検出された。また急変直前に使用されたとされるイオパミドールが同定されたことから，イオパミドールによるアナフィラキシーショックが死因である可能性が高いと診断した。また，適切な処置を行ったにもかかわらず死亡に至った背景として，心予備能の低下やKounis症候群が関与した可能性が示唆された。本事例では初めて死後検体からイオパミドールの同定・定量を行っており，アナフィラキシー発症は濃度非依存的であるものの，重要なデータになると考えらえた。

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.

The present study aimed to investigate the correlation between palatal suture obliteration and age in modern Japanese and to develop an age estimation equation by modifying Kamijo's (1949) method. The subjects were 195 Japanese skeletal remains (155 males and 40 females) whose age and sex were known. First, obliteration score (OS) was obtained by measuring palatal suture obliteration from photographic images taken at the time of forensic autopsy, and the correlation with age was examined; no significant correlation was found in females. Second, the palatal sutures were divided into 14 sections, and each section was scored from 0 to 4 points according to the degree of the suture obliteration. Suture scores (SS) were then calculated for each of the four sutures, and the sum of the 14 scores (TSS: total suture score) was used to perform regression analysis for age. For male and all subjects (male and female), age significantly increased (p < 0.001) according to increment of SSs for all sutures. TSS has the highest regression coefficient (r = 0.540), and the lowest standard error of estimation (13.54 years) for all of the patients. The intra- and inter-observer agreement scoring showed high reliability. Validation study using the formulae showed a high percentage of correct responses (80 %). In conclusion, age estimation regression formula by palatal suture using modified Kamijo's method was established for Japanese population, and the study showed the formula might be valid for age estimation.

The present study aimed to investigate the correlation between palatal suture obliteration and age in modern Japanese and to develop an age estimation equation by modifying Kamijo's (1949) method. The subjects were 195 Japanese skeletal remains (155 males and 40 females) whose age and sex were known. First, obliteration score (OS) was obtained by measuring palatal suture obliteration from photographic images taken at the time of forensic autopsy, and the correlation with age was examined; no significant correlation was found in females. Second, the palatal sutures were divided into 14 sections, and each section was scored from 0 to 4 points according to the degree of the suture obliteration. Suture scores (SS) were then calculated for each of the four sutures, and the sum of the 14 scores (TSS: total suture score) was used to perform regression analysis for age. For male and all subjects (male and female), age significantly increased (p < 0.001) according to increment of SSs for all sutures. TSS has the highest regression coefficient (r = 0.540), and the lowest standard error of estimation (13.54 years) for all of the patients. The intra- and inter-observer agreement scoring showed high reliability. Validation study using the formulae showed a high percentage of correct responses (80 %). In conclusion, age estimation regression formula by palatal suture using modified Kamijo's method was established for Japanese population, and the study showed the formula might be valid for age estimation.

In forensic pathology, it is important to detect and recover as evidence residual metal particles and projectiles when evaluating potential gunshot wounds. This process can be challenging when the bullets are fragmented. This report presents our experience using multiple modalities to analyze the wound of an illegally killed Japanese serow (Capricornis crispus) found in a mountainous region without its head and hind limbs. We performed postmortem computed tomography (PMCT) and necropsy that showed a distant-range gunshot wound of the neck likely created by a centerfire rifle. A postmortem cut through the neck and absent head precluded a complete evaluation. To determine the composition of the metal-like fragments in the neck, sampling and metal analysis were performed in two ways. Samples extracted from the exposed wound surface without CT guidance were analyzed directly using inductively coupled plasma mass spectrometry (ICP-MS). Samples from the bone, muscles, and cervical cord extracted under CT guidance were analyzed using x-ray analytic microscopy (XGT-9000, HORIBA, Kyoto, Japan). In wound surface samples, silicon and iron were detected as the main components on ICP-MS, suggesting that the materials were gravel. The samples taken under CT guidance and analyzed with XGT-9000 revealed that the high-density CT areas were mainly composed of lead. Combining CT-guided sample extraction and XGT-9000 can be useful for retrieving true projectile fragments and avoiding the confusion created by erroneously sampling non-projectile surface materials.

OBJECTIVES: The prolonged presence of infectious SARS-CoV-2 in deceased patients with COVID-19 has been reported. However, infectious virus titers have not been determined. Such information is important for public health, death investigation, and handling corpses. The aim of this study was to assess the level of SARS-CoV-2 infectivity in the corpses of patients with COVID-19. METHODS: We collected 11 nasopharyngeal swabs and 19 lung tissue specimens from 11 autopsy cases with COVID-19 in 2021. We then investigated the viral genomic copy number by real-time reverse transcription-polymerase chain reaction and infectious titers by cell culture and virus isolation. RESULTS: Infectious virus was present in six of 11 (55%) cases, four of 11 (36%) nasopharyngeal swabs, and nine of 19 (47%) lung specimens. The virus titers ranged from 6.00E + 01 plaque-forming units/ml to 2.09E + 06 plaque-forming units/g. In all cases in which an infectious virus was found, the time from death to discovery was within 1 day and the longest postmortem interval was 13 days. CONCLUSION: The corpses of patients with COVID-19 may have high titers of infectious virus after a long postmortem interval (up to 13 days). Therefore, appropriate infection control measures must be taken when handling corpses.

Insulin preparations, which are drug treatments for diabetes, cause fatal hypoglycemia when an overdose is administered. Cases of homicide and suicide using these preparations have been reported and are of great forensic interest. However, there are few reports assessing the postmortem concentration of insulin preparations, and it is often difficult to determine the cause of death. In the present study, we report a case of a suspected insulin glargine and insulin lispro overdose for suicide. A woman in her 30s had a history of mental illness and diabetes. The day before her death, she reported to her boyfriend that she had taken large doses of insulin preparations and prescription drugs. An autopsy revealed no fatal injuries or lesions. Drug screening tests revealed several prescription drugs, none of which showed toxic concentrations. Analysis using LC-MS/MS detected insulin glargine in the peripheral and cardiac blood at 429 μU/mL and 1362 μU/mL, respectively, whereas insulin lispro was detected in both the peripheral and cardiac blood at levels below the lower limit of quantification (LLOQ; <50 μU/mL). The cause of death was considered likely to be hypoglycemia caused by an overdose of insulin glargine. Insulin glargine is rapidly metabolized after subcutaneous administration and is rarely detected in the blood when used at therapeutic doses. There are no other reports on the quantification of insulin glargine parent compounds in postmortem samples, and this case provides important data on postmortem blood concentrations of insulin glargine intoxication.

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.

Occupational accidental injury deaths (OAIDs) are a major social problem, and the analysis of individual cases is important for developing injury prevention measures. In this study, OAIDs with autopsies performed at forensic facilities in the metropolitan area of Japan (Tokyo and Chiba prefectures) from 2011 to 2020 were reviewed. The epidemiological characteristics of these OAIDs (n = 136), which accounted for 13.5% of OAIDs reported in the region during the study period, were compared with those of non-occupational accidental injury deaths (non-OAID) cases (n = 3926). Among OAID cases, 134 (98.5%) were men and 13 (9.6%) were foreign-born workers, which was significantly more than in non-OAID cases (p < 0.001, respectively). OAIDs were most frequent in construction (39.0%) followed by the manufacturing category (21.3%). The percentage of OAIDs in workers aged 65 and over showed an increasing trend. Most accidents occurred just after the start of work or just before the workday ended, as well as during the peak months of the year. The most common type of accident was fall/crash from a height (25.0%), and the most common injury site was the chest; none of these cases were confirmed to have been wearing a safety belt properly. Among foreign-born workers, the most common type of accident was caught in/between. As the working population is expected to change in the future, and an increase in the number of older adults and foreign workers is expected, it is necessary to take preventive measures such as improving the work environment based on ergonomics and providing safety education.

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.

Acupuncture is practiced as a complementary medicine worldwide. Although it is considered a safe practice, pneumothorax is one of its most common serious complications. However, there have been few reports of deaths due to pneumothorax after acupuncture treatment, especially focused on electroacupuncture. We report an autopsy case of a man in his 60s who went into cardiopulmonary arrest and died immediately after receiving electroacupuncture. Postmortem computed tomography (PMCT) showed bilateral pneumothoraces, as well as the presence of numerous gold threads embedded subcutaneously. An autopsy revealed two ecchymoses in the right thoracic cavity and a pinhole injury on the lower lobe of the right lung, suggesting that the needles had penetrated the lung. There were marked emphysematous changes in the lung, suggesting that rupture of bullae might also have contributed to bilateral pneumothoraces and fatal outcome. The acupuncture needles may have been drawn deeper into the body than at the time of insertion due to electrical pulses and muscle contraction, indicating the need for careful determination of treatment indications and technical safety measures, such as fail-safe mechanisms. This is the first case report of fatal bilateral pneumothoraces after electroacupuncture reported in the English literature. This case sheds light on the safety of electroacupuncture and the need for special care when administering it to patients with pulmonary disease who may be at a higher risk of pneumothorax. This is also the first report of three-dimensional reconstructed PMCT images showing the whole-body distribution of embedded gold acupuncture threads, which is unusual.

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.

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.

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.

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.

In recent years, there has been an increase in the use of phosphodiesterase type 5 inhibitors (PDE5i) that are purchased from abroad without a doctor's diagnosis via the Internet or other means. We report six cases in which nonprescription use of PDE5i may have led to death. Among the four deceased individuals who were believed to have experienced sudden cardiac death, three (cases 1-3) had a history of cardiovascular disease, which is a contraindication, and the remaining case (case 4) involved combined use of multiple PDE5i. Sildenafil (0.063 µg/mL, 0.087 µg/mL) was detected in two of the four cases of sudden cardiac death. Tadalafil (0.096 µg/mL) was detected in one of the remaining two cases, and tadalafil (0.197 µg/mL) and vardenafil (0.011 µg/mL) were detected in the other case. Sildenafil (0.032 µg/mL), tadalafil (0.062 µg/mL), and ethanol were detected in a traffic accident case with a history of contraindications. In a case of asphyxiation by vomit aspiration, autopsy showed 90% stenosis in the anterior descending branch of the coronary artery, and sildenafil (0.063 µg/mL) was detected. To the best of our knowledge, this is the first report of postmortem blood levels of tadalafil and vardenafil likely contributing to the cause of death. Despite all the warnings about the dangers of using PDE5 inhibitors, cases of PDE5i contributing to death are still identified during autopsies. Therefore, raising public awareness of the risks of the risks associated with the imported drug use by individuals is necessary.

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.