Gray-Scale Extraction of Bone Features from Chest Radiographs Based on Deep Learning Technique for Personal Identification and Classification in Forensic Medicine.

Post-mortem (PM) imaging has potential for identifying individuals by comparing ante-mortem (AM) and PM images. Radiographic images of bones contain significant information for personal identification. However, PM images are affected by soft tissue decomposition; therefore, it is desirable to extract only images of bones that change little over time. This study evaluated the effectiveness of U-Net for bone image extraction from two-dimensional (2D) X-ray images. Two types of pseudo 2D X-ray images were created from the PM computed tomography (CT) volumetric data using ray-summation processing for training U-Net. One was a projection of all body tissues, and the other was a projection of only bones. The performance of the U-Net for bone extraction was evaluated using Intersection over Union, Dice coefficient, and the area under the receiver operating characteristic curve. Additionally, AM chest radiographs were used to evaluate its performance with real 2D images. Our results indicated that bones could be extracted visually and accurately from both AM and PM images using U-Net. The extracted bone images could provide useful information for personal identification in forensic pathology.

Distinguishing true from pseudo hematoma in the cervical spinal canal using postmortem computed tomography.

Spinal cord injury is difficult to detect directly on postmortem computed tomography (PMCT) and it is usually diagnosed by indirect findings such as a hematoma in the spinal canal. However, we have encountered cases where the hematoma-like high-attenuation area in the cervical spinal canal was visible on PMCT, while no hematoma was observed at autopsy; we called it a "pseudo hematoma in the cervical spinal canal (pseudo-HCSC)." In this retrospective study, we performed statistical analysis to distinguish true from pseudo-HCSC. The cervical spinal canal was dissected in 35 autopsy cases with a hematoma-like high-attenuation area (CT values 60-100 Hounsfield Unit (HU)) in the spinal canal from the first to the fourth cervical vertebrae in axial slices of PMCT images. Of these 22 had a hematoma and 13 did not (pseudo-HCSC). The location and length of the hematoma-like high-attenuation and spinal cord areas were assessed on reconstructed PMCT images, true HCSC cases had longer the posterior hematoma-like area and shorter the spinal cord area in the midline of the spinal canal (P < 0.05). Furthermore, we found that true HCSC cases were more likely to have fractures and gases on PMCT while pseudo-HCSC cases were more likely to have significant facial congestion (P < 0.05). We suggest that pseudo-HCSC on PMCT is related to congestion of the internal vertebral venous plexus. This study raises awareness about the importance of distinguishing true HCSC from pseudo-HCSC in PMCT diagnosis, and it also presents methods for differentiation between these two groups.

Quantitative analysis of respiratory viral distribution in forensic autopsy cases.

Respiratory viruses can cause fatal systemic infections; therefore, post-mortem diagnosis is essential in forensic autopsy cases. However, little is known regarding the distribution of respiratory viruses in the body. In this study, we investigated the anatomical distribution of respiratory viruses in 48 forensic autopsy cases suspected of viral infections at our institute. Fast Track Diagnostics (FTD) Respiratory Pathogens 21 was used as a screening test for 20 respiratory viruses in nasopharyngeal swabs. In cases with positive results for virus detection by the screening test, the detected viruses were quantified in body fluid and organ specimens by virus-specific real-time reverse transcription polymerase chain reaction (RT-PCR) and digital PCR. Viruses were detected in 33 cases, with the viral distribution and load differing among the cases. Since various respiratory viruses were detected from the nasopharyngeal swab and its viral load was higher than those of other body fluid specimens, the nasopharyngeal swab was suggested as a useful specimen for the post-mortem detection of respiratory viruses. Viruses were detected in almost all specimens including the serum in six cases. Considering the viral distribution in the body, pathological findings, and ante-mortem symptoms, these cases were presumed to be systemically infected, having died in the acute infection phase. In conclusion, the anatomical distribution of respiratory viruses can help indicate ante-mortem systemic conditions and the cause of death.

Death by fecaloma.

A 59-year-old man with a history of cerebral palsy and dextroscoliosis died in a group home. He required supplemental oxygen and had no bowel movement for weeks prior to death. At autopsy, the abdomen was markedly distended and there were flexion contractures of the legs. Postmortem computed tomography revealed a dilated digestive tract and fecal loading in the sigmoid and rectum, marked upwardly displaced diaphragm and scoliosis. On internal examination, the diaphragm was displaced rostrally and the rectosigmoid colon contained 2.5 kg of fecaloma with two rectal fecaliths. Severe scoliosis with marked reduction in volume of thoracic cavity was present. Microscopic examination revealed chronic aspiration pneumonia and chronic pulmonary hypertension. Overall, four factors led to respiratory failure: fecaloma; cerebral palsy; scoliosis; and chronic aspiration pneumonia. Based on clinicopathological correlation, the cause of death was determined to be a combination of these factors, and the key acute factor was the fecaloma.

Kinetics and distribution of benzalkonium compounds with different alkyl chain length following intravenous administration in rats.

Benzalkonium chloride is widely used in disinfectants. Several toxicological and fatal cases have been reported; however, little is known about its kinetics and distribution. We investigated the kinetic characteristics and distribution of benzalkonium cation (BZK) based on the length of the alkyl chains C12, C14, and C16. Rats were treated intravenously with BZK solution (dose, 13.9 mg/kg) containing equal amounts of the three homologues. Kinetic parameters in the blood were assessed, and BZK distribution in the blood and tissues was examined both in rapid intravenous (IV) and drip intravenous (DIV) administrations. BZK concentrations were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). BZK with longer alkyl chains showed lower elimination tendencies and remained in the blood for a longer duration. Concentrations of BZK were higher in the heart, lung, spleen, and kidney than those in the blood, and lower in the brain and fat. In both the IV and DIV groups, the lung, liver, spleen, and fat samples showed higher concentrations of the longer alkyl chains (BZK-C12 < -C14 < -C16), and the opposite trend was observed in the kidney (BZK-C16 < -C14 < -C12). Only the heart and muscle samples displayed the homologues in ratios comparable to the original administered solutions. Differences between IV and DIV groups could be identified by comparing concentrations of BZK homologues in the heart, lung, spleen, and kidney samples. We found that the kinetics and distribution of BZK were influenced by the alkyl chain length, and analysing each BZK homologues in blood and tissue samples may provide useful information.

The derivation of predictive equations to speculate the post-mortem interval using cases with over 20-mL pleural effusion: A preliminary study.

Often, pleural effusion is noted at autopsy when the cause of death is drowning or diseases such as heart, renal and liver failure. Several studies have established a correlation between the concentrations of electrolytes in pleural effusion and the post-mortem interval (PMI) or those concentrations and drowning site. The present study aims to investigate the relationship between the amount of pleural effusion, concentrations of electrolytes and total protein in pleural effusion, by integrated interpretation using various factors such as the deceased's gender, age, cause of death, drowning site, PMI and body temperature. We included 40 cadavers (26 male, 14 female) with >20-mL pleural effusion, which were categorised into four groups as follows: freshwater drowning; brackish water drowning; seawater drowning (drowning group); and not drowning. An equation derived to assess the lung weight revealed that the drowning site affected the lung weight. An equation for the amount of pleural effusion in the drowning group for the first time revealed that the amount of pleural effusion was directly proportional to the PMI. Using an equation to assess the PMI, we could estimate the PMI within 13.0-13.2 h in cases with >20-mL pleural effusion. Despite a small number of cases in the present study, we attained exciting results from the integrated statistical analysis.

Predictive equation for post-mortem interval using spectrophotometric values of post-mortem lividity: A pilot study.

The colour of post-mortem lividity and control skin of 86 cadavers was measured spectrophotometrically to obtain L* (value), a* (chroma) and b* (hue) values. In addition, left heart blood (n = 58), right heart blood (n = 57) and blood from the femoral vein (n = 21) were measured. Using these data, we analysed the relationship between post-mortem lividity, control skin and blood colours. L* of post-mortem lividity (L*p) and control skin (L*c) were strongly correlated ( r = 0.64). a* and b* of post-mortem lividity (a*p and b*p) significantly increased with an increasing post-mortem interval (PMI) but r2 values were low (0.11 and 0.070, respectively). Predictive equations for post-mortem lividity colour (L*p, a*p and b*p) were developed using control skin colour (L*c, a*c and b*c) and autopsy findings for the first time. The predictive equation for L*p explained almost 65% of the observed L*p. We created predictive equations for PMI with and without blood colour values, and the most accurate equation, which did not use blood colour values, made it possible to estimate PMI within ± 10.29 h. Further study of these equations will help us to understand the factors that affect post-mortem lividity colour and increase the accuracy of equations for predicting post-mortem lividity colour and PMI.

Predictive equation to estimate post-mortem interval using spectrophotometric blood-colour values.

Forensic pathologists use post-mortem phenomena to estimate the post-mortem interval (PMI). We have reported on the usefulness of post-mortem lividity spectrophotometric values to estimate PMIs. Here, we focused on blood colour, looking for associations between blood colour, age and PMI. We generated predictive equations for blood-colour values and the PMI. We included data from a total of 129 cadavers (84 males and 45 females). We measured the colour of 124 left ventricular blood ( L*l, a*l, b*l), 123 right ventricular blood ( L*r, a*r, b*r) and 57 femoral blood ( L*f, a*f, b*f) samples. We found no significant associations between blood colour and age or between blood colour and the PMI, but the values of a*l, b*l, a*r and b*r were significantly increased with increased age, and those of L*f, a*f and b*f were significantly decreased with increased PMI. We created equations to estimate blood colour. The equations for femoral blood colour had higher adjusted R2 values and lower root mean square error values than those for left and right ventricular blood colours. We generated equations to estimate PMIs using blood-colour values and autopsy findings. Our estimated PMIs up to 67 hours had accuracies within 8.84 hours, without measuring post-mortem lividity colour or considering the age of the deceased. This is the first study to estimate PMIs based on blood-colour spectrophotometric values.

Postmortem interval estimation using the animal model of postmortem gas volume changes.

It is important to estimate the postmortem interval in forensic autopsy. Many methods to estimate the postmortem interval have been reported, and are typically associated with internal examination. However, there are issues such as rejection of autopsy by the family and a lack of forensic doctor in internal examination. Therefore, it is necessary to develop new methods, such as autopsy imaging, that can substitute for internal examination. Here, we first evaluated whether gas volume in the body increased with postmortem interval. Time-dependent X-ray CT imaging of euthanized Crl:CD (SD) rats (n = 3) was performed immediately after euthanasia and at seven subsequent time points up to 168 h (7 days) at 24-hour intervals. The data revealed that gas volume in the body increased in a time-dependent manner. Next, we reconstructed 3D images of isolated gas and calculated the gas volume using Amira software. In all cases, the volume of both portal venous gas and intestinal gas increased in a time-dependent manner. The volume of portal venous gas increased exponentially, while the volume of intestinal gas increased in a linearly with time. These data might be suggested that the postmortem gas volume change is one of indicators for estimating the postmortem interval. In addition, it would be possible to estimate more accurate postmortem interval by combining not only gas volume changes at the above two sites but also gas volume changes of the other sites such as heart cavities, kidney parenchyma, or abdominal aorta.

Bone comparison identification method based on chest computed tomography imaging.

The aim of this study is to examine the usefulness of bone structure extracted data from chest computed tomography (CT) images for personal identification. Eighteen autopsied cases (12 male and 6 female) that had ante- and post-mortem (AM and PM) CT images were used in this study. The two-dimensional (2D) and three-dimensional (3D) bone images were extracted from the chest CT images via thresholding technique. The similarity between two thoracic bone images (consisting of vertebrae, ribs, and sternum) acquired from AMCT and PMCT images was calculated in terms of the normalized cross-correlation value (NCCV) in both 2D and 3D matchings. An AM case with the highest NCCV corresponding to a given PM case among all of the AM cases studied was regarded as same person. The accuracy of identification of the same person using our method was 100% (18/18) in both 2D and 3D matchings. The NCCVs for the same person tended to be significantly higher than the average of NCCVs for different people in both 2D and 3D matchings. The computation times of image similarity between the two images were less than one second and approximately 10min in 2D and 3D matching, respectively. Therefore, 2D matching especially for thoracic bones seems more advantageous than 3D matching with regard to computation time. We conclude that our proposed personal identification method using bone structure would be useful in forensic cases.

Sex determination based on a thoracic vertebra and ribs evaluation using clinical chest radiography.

Our aim was to investigate whether sex can be determined from a combination of geometric features obtained from the 10th thoracic vertebra, 6th rib, and 7th rib. Six hundred chest radiographs (300 males and 300 females) were randomly selected to include patients of six age groups (20s, 30s, 40s, 50s, 60s, and 70s). Each group included 100 images (50 males and 50 females). A total of 14 features, including 7 lengths, 5 indices for the vertebra, and 2 types of widths for ribs, were utilized and analyzed for sex determination. Dominant features contributing to sex determination were selected by stepwise discriminant analysis after checking the variance inflation factors for multicollinearity. The accuracy of sex determination using a combination of the vertebra and ribs was evaluated from the selected features by the stepwise discriminant analysis. The accuracies in each age group were also evaluated in this study. The accuracy of sex determination based on a combination of features of the vertebra and ribs was 88.8% (533/600). This performance was superior to that of the vertebra or ribs only. Moreover, sex determination of subjects in their 20s demonstrated the highest accuracy (96.0%, 96/100). The features selected in the stepwise discriminant analysis included some features in both the vertebra and ribs. These results indicate the usefulness of combined information obtained from the vertebra and ribs for sex determination. We conclude that a combination of geometric characteristics obtained from the vertebra and ribs could be useful for determining sex.

Analysis of postmortem changes in internal organs and gases using computed tomography data.

Postmortem computed tomography (PMCT) is a useful method to identify various causes of death and measure the volume of internal organs and gases. The purpose of this study was to investigate postmortem changes as measured by PMCT, and the relationship between the volume of organs and gases and postmortem interval (PMI). Forty-six cadavers (22 men, 24 women) were examined by CT before autopsy. The volumes of the lungs, intrahepatic gas, and intrarectal gas were measured by CT using a workstation. A stepwise regression analysis was used to establish a predictive equation to ascertain the measured volume using factors including sex, age, height, body mass index (BMI), body surface area (BSA), and PMI. For estimation of PMI, stepwise regression analysis was used. In the equations for each measured volume, height, diaphragmatic height, and BSA were adopted for the left lung; height and diaphragmatic height were adopted for the right lung; PMI was adopted for intrahepatic gas; and sex and PMI were adopted for intrarectal gas. In the PMI equations, left lung volume, intrahepatic gas, and intrarectal gas were adopted together with sex, weight, and BMI. Values of intrahepatic gas decreased with postmortem changes, while intrarectal gas increased. This may be useful in investigation of postmortem changes. It will be necessary to include other parts of the intestine and to analyze volume changes in gases from these parts after death.

Expression of mRNA in the frontal cortex and hypothalamus in a rat model of acute carbon dioxide poisoning.

Acute carbon dioxide (CO2) poisoning causes no specific features that are revealed upon autopsy, and the pathophysiological mechanism of this syndrome is unclear. To address this issue, in the present study, we exposed rats to CO2 concentrations ranging from 10% to 60% and determined the effects on mRNA expression. According to the results of Gene Ontology (GO) and cluster analyses of microarrays data, we selected the following genes for further analysis: alkylglycerone phosphate synthase (Agps), hypocretin (Hcrt), tyrosine hydroxylase (Th), heat shock protein beta 2 (Hspb2), and opioid receptor delta 1 (Oprd1) expressed in the frontal cortex and renin (Ren), pancreatic polypeptide (Ppy), corticotropin releasing hormone receptor 2 (Crhr2), carbonic anhydrase 1 (Car1), and hypocretin receptor 1 (Hcrtr1) expressed in the hypothalamus. We found significant differences between the expression levels of Agps and Hspb2 mRNAs in the frontal cortex and that of Ppy, Crhr2 mRNAs in the hypothalamus in the presence of high concentrations of CO2. Further investigation of these genes may clarify the pathophysiology of acute CO2 poisoning and facilitate the development of novel forensic tests that can diagnose the cause of death.

[An Autopsy Case of Abnormal Behaviour Induced by Zolpidem].

Zolpidem is a widely used ultrashort-acting non-benzodiazepine in clinical practice; compared with benzodiazepines, it does not have side effects such as daytime hangover, rebound insomnia, and development of tolerance. We report an autopsy case of abnormal behaviour induced by zolpidem. A man in his 60's had suffered from postherpetic neuralgia about 2 months ago and had been prescribed zolpidem for insomnia. According to his family, he had no memory of his actions such as striking a wall, taking his futon outside, and eating 5 times a day after he took zolpidem. Because his postherpetic neuralgia did not improve, he was hospitalized and treated with an epidural block. During hospitalization, he took off his clothes, removed the epidural block catheter by himself, and slept on others' beds. He disappeared from the hospital one day; the next day, he was found dead in a narrow water storage tank 10 km away from the hospital. He was thought to have driven a car by himself to reach the place. Forensic autopsy revealed that the cause of death was drowning. Zolpidem and several other drugs were detected by toxicological analysis of his blood; the concentrations of these drugs were within therapeutic range. There are several reports about somnambulism induced by zolpidem such as sleepwalking, sleep driving, and eating. Considering the strange episodes following zolpidem administration, his behaviour on the day of his death was considered abnormal behaviour induced by zolpidem.

A fatal case of poisoning related to new cathinone designer drugs, 4-methoxy PV8, PV9, and 4-methoxy PV9, and a dissociative agent, diphenidine.

A woman in her thirties was found dead on a bed. Considerable amounts of "aroma liquid" and "bath salt" products and hypnotic drug tablets were scattered beside the bed. Autopsy showed pulmonary congestion and edema. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) analyses of "aroma liquid" and "bath salt" products showed the presence of new cathinone designer drugs, 4-methoxy PV8 (4-methoxy PHPP), PV9 (α-POP), and 4-methoxy PV9 (4-methoxy α-POP), and a dissociative agent, diphenidine. Drug screening in stomach contents, blood and hydrolyzed urine of the woman by GC-MS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed the presence of the above 4 types of drugs and 3 types of benzodiazepines, triazolam, flunitrazepam, and nitrazepam, and their metabolites. The above 7 drugs and 3 benzodiazepine metabolites were simultaneously determined by LC-MS/MS after modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction using diazepam-d5 as the internal standard. The concentrations of 4-methoxy PV8, PV9, 4-methoxy PV9, and diphenidine in the femoral blood were 2.69, 0.743, 0.261, and 1.38µg/ml, respectively, which were significantly higher than concentrations reported in previous cases. Alcohol concentration in the femoral blood was 1.52mg/ml. Based on the pathological and toxicological findings, the cause of death was determined to be 3 types of cathinone drugs, 4-methoxy PV8, PV9, and 4-methoxy PV9, and diphenidine poisoning under the influence of 3 benzodiazepines and alcohol.

Medical neglect death due to acute lymphoblastic leukaemia: an autopsy case report.

We report the case of 2-year-old girl who died of precursor B-cell acute lymphoblastic leukaemia (ALL), the most common cancer in children. She had no remarkable medical history. She was transferred to a hospital because of respiratory distress and died 4 hours after arrival. Two weeks before death, she had a fever of 39 degrees C, which subsided after the administration of a naturopathic herbal remedy. She developed jaundice 1 week before death, and her condition worsened on the day of death. Laboratory test results on admission showed a markedly elevated white blood cell count. Accordingly, the cause of death was suspected to be acute leukaemia. Forensic autopsy revealed the cause of death to be precursor B-cell ALL. With advancements in medical technology, the 5-year survival rate of children with ALL is nearly 90%. However, in this case, the deceased's parents preferred complementary and alternative medicine (i.e., naturopathy) to evidence-based medicine and had not taken her to a hospital for a medical check-up or immunisation since she was an infant. Thus, if she had received routine medical care, she would have a more than 60% chance of being alive 5 years after diagnosis. Therefore, we conclude that the parents should be accused of medical neglect regardless of their motives.

Assessment of some problematic factors in facial image identification using a 2D/3D superimposition technique.

The number of criminal cases requiring facial image identification of a suspect has been increasing because a surveillance camera is installed everywhere in the city and furthermore, the intercom with the recording function is installed in the home. In this study, we aimed to analyze the usefulness of a 2D/3D facial image superimposition system for image identification when facial aging, facial expression, and twins are under consideration. As a result, the mean values of the average distances calculated from the 16 anatomical landmarks between the 3D facial images of the 50s groups and the 2D facial images of the 20s, 30s, and 40s groups were 2.6, 2.3, and 2.2mm, respectively (facial aging). The mean values of the average distances calculated from 12 anatomical landmarks between the 3D normal facial images and four emotional expressions were 4.9 (laughter), 2.9 (anger), 2.9 (sadness), and 3.6mm (surprised), respectively (facial expressions). The average distance obtained from 11 anatomical landmarks between the same person in twins was 1.1mm, while the average distance between different person in twins was 2.0mm (twins). Facial image identification using the 2D/3D facial image superimposition system demonstrated adequate statistical power and identified an individual with high accuracy, suggesting its usefulness. However, computer technology concerning video image processing and superimpose progress, there is a need to keep familiar with the morphology and anatomy as its base.

A familial case of ABO phenotype-genotype discrepancy.

In the present study, we detected a familial case of ABO phenotype-genotype discrepancy. Although the observed phenotypes were B and O, the corresponding ABO genotypes were AB and AOG, respectively, by routine examination. Exons 6 and 7 of the ABO gene were sequenced and subsequently, the sequence of the allele responsible for ABO phenotype-genotype discrepancy was examined. Our results indicated that the Ax allele was present in 3 family members. By employing traditional serological methods, we further identified and confirmed that the allele Ax and the resulting Ax phenotype are responsible for ABO phenotype-genotype discrepancy.

Rapid and reliable screening method for detection of 70 pesticides in whole blood by gas chromatography-mass spectrometry using a constructed calibration-locking database.

Pesticide poisoning is one of the most common causes of death by poisoning in Japan, and various kinds of pesticides including organophosphates, carbamates and pyrethroids are listed as causative substances. The purpose of our study was to develop a rapid and reliable screening method for various kinds of pesticides in whole blood by using a unique calibration-locking database and gas chromatography-mass spectrometry. A database of 70 pesticides was constructed using NAGINATA™ software with parameters such as mass spectrum, retention time and qualifier ion/target ion ratio (QT ratio) and calibration curve. Diazepam-d(5) was used as the internal standard for construction of each calibration curve within the range of 0.01-5.0 µg/ml. We examined the applicability of the constructed database by analyzing whole blood samples spiked with 70 pesticides. The pesticides in blood were extracted with hexane under acidic conditions or with an enhanced polymer column (Focus™), subjected to GC-MS, and screened by the pesticides database. Among the 70 pesticides examined, 66 and 62 were successfully identified at the level of 1 and 0.1 µg/ml, respectively, by hexane and 63 and 51 were identified by the Focus column without the use of standard compounds. The time required for data analysis was significantly reduced. Since the established method can produce qualitative and semi-quantitative data without the need for standard substances, this new screening method using NAGINATA™ should be useful for confirming the presence of pesticides in blood in future clinical and forensic cases.